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Coviello AD, Haring R, Wellons M, Vaidya D, Lehtimäki T, Keildson S, Lunetta KL, He C, Fornage M, Lagou V, Mangino M, Onland-Moret NC, Chen B, Eriksson J, Garcia M, Liu YM, Koster A, Lohman K, Lyytikäinen LP, Petersen AK, Prescott J, Stolk L, Vandenput L, Wood AR, Zhuang WV, Ruokonen A, Hartikainen AL, Pouta A, Bandinelli S, Biffar R, Brabant G, Cox DG, Chen Y, Cummings S, Ferrucci L, Gunter MJ, Hankinson SE, Martikainen H, Hofman A, Homuth G, Illig T, Jansson JO, Johnson AD, Karasik D, Karlsson M, Kettunen J, Kiel DP, Kraft P, Liu J, Ljunggren Ö, Lorentzon M, Maggio M, Markus MRP, Mellström D, Miljkovic I, Mirel D, Nelson S, Morin Papunen L, Peeters PHM, Prokopenko I, Raffel L, Reincke M, Reiner AP, Rexrode K, Rivadeneira F, Schwartz SM, Siscovick D, Soranzo N, Stöckl D, Tworoger S, Uitterlinden AG, van Gils CH, Vasan RS, Wichmann HE, Zhai G, Bhasin S, Bidlingmaier M, Chanock SJ, De Vivo I, Harris TB, Hunter DJ, Kähönen M, Liu S, Ouyang P, Spector TD, van der Schouw YT, Viikari J, Wallaschofski H, McCarthy MI, Frayling TM, Murray A, Franks S, Järvelin MR, de Jong FH, Raitakari O, Teumer A, Ohlsson C, Murabito JM, Perry JRB. A genome-wide association meta-analysis of circulating sex hormone-binding globulin reveals multiple Loci implicated in sex steroid hormone regulation. PLoS Genet 2012; 8:e1002805. [PMID: 22829776 PMCID: PMC3400553 DOI: 10.1371/journal.pgen.1002805] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 05/19/2012] [Indexed: 01/28/2023] Open
Abstract
Sex hormone-binding globulin (SHBG) is a glycoprotein responsible for the transport and biologic availability of sex steroid hormones, primarily testosterone and estradiol. SHBG has been associated with chronic diseases including type 2 diabetes (T2D) and with hormone-sensitive cancers such as breast and prostate cancer. We performed a genome-wide association study (GWAS) meta-analysis of 21,791 individuals from 10 epidemiologic studies and validated these findings in 7,046 individuals in an additional six studies. We identified twelve genomic regions (SNPs) associated with circulating SHBG concentrations. Loci near the identified SNPs included SHBG (rs12150660, 17p13.1, p = 1.8 × 10(-106)), PRMT6 (rs17496332, 1p13.3, p = 1.4 × 10(-11)), GCKR (rs780093, 2p23.3, p = 2.2 × 10(-16)), ZBTB10 (rs440837, 8q21.13, p = 3.4 × 10(-09)), JMJD1C (rs7910927, 10q21.3, p = 6.1 × 10(-35)), SLCO1B1 (rs4149056, 12p12.1, p = 1.9 × 10(-08)), NR2F2 (rs8023580, 15q26.2, p = 8.3 × 10(-12)), ZNF652 (rs2411984, 17q21.32, p = 3.5 × 10(-14)), TDGF3 (rs1573036, Xq22.3, p = 4.1 × 10(-14)), LHCGR (rs10454142, 2p16.3, p = 1.3 × 10(-07)), BAIAP2L1 (rs3779195, 7q21.3, p = 2.7 × 10(-08)), and UGT2B15 (rs293428, 4q13.2, p = 5.5 × 10(-06)). These genes encompass multiple biologic pathways, including hepatic function, lipid metabolism, carbohydrate metabolism and T2D, androgen and estrogen receptor function, epigenetic effects, and the biology of sex steroid hormone-responsive cancers including breast and prostate cancer. We found evidence of sex-differentiated genetic influences on SHBG. In a sex-specific GWAS, the loci 4q13.2-UGT2B15 was significant in men only (men p = 2.5 × 10(-08), women p = 0.66, heterogeneity p = 0.003). Additionally, three loci showed strong sex-differentiated effects: 17p13.1-SHBG and Xq22.3-TDGF3 were stronger in men, whereas 8q21.12-ZBTB10 was stronger in women. Conditional analyses identified additional signals at the SHBG gene that together almost double the proportion of variance explained at the locus. Using an independent study of 1,129 individuals, all SNPs identified in the overall or sex-differentiated or conditional analyses explained ~15.6% and ~8.4% of the genetic variation of SHBG concentrations in men and women, respectively. The evidence for sex-differentiated effects and allelic heterogeneity highlight the importance of considering these features when estimating complex trait variance.
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Affiliation(s)
- Andrea D. Coviello
- Section of Preventive Medicine and Epidemiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, Massachusetts, United States of America
- National Heart, Lung, and Blood Institute's The Framingham Heart Study, Framingham, Massachusetts, United States of America
| | - Robin Haring
- Institute for Clinical Chemistry and Laboratory Medicine, University Medicine, Ernst-Moritz-Arndt University of Greifswald, Greifswald, Germany
| | - Melissa Wellons
- Department of Medicine and Department of Obstetrics and Gynecology, The University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Dhananjay Vaidya
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Terho Lehtimäki
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere University Hospital and University of Tampere School of Medicine, Tampere, Finland
| | - Sarah Keildson
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Kathryn L. Lunetta
- Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, United States of America
| | - Chunyan He
- Department of Public Health, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- Melvin and Bren Simon Cancer Center, Indiana University, Indianapolis, Indiana, United States of America
| | - Myriam Fornage
- University of Texas Health Sciences Center at Houston, Houston, Texas, United States of America
| | - Vasiliki Lagou
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Oxford, United Kingdom
| | - Massimo Mangino
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - N. Charlotte Onland-Moret
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Brian Chen
- Program on Genomics and Nutrition and the Center for Metabolic Disease Prevention, School of Public Health, University of California Los Angeles, Los Angeles, California, United States of America
| | - Joel Eriksson
- Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Melissa Garcia
- Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, Maryland, United States of America
| | - Yong Mei Liu
- Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
- Department of Epidemiology and Prevention, Division of Public Health Sciences, Wake Forest University Health Sciences, Winston-Salem, North Carolina, United States of America
| | - Annemarie Koster
- Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, Maryland, United States of America
| | - Kurt Lohman
- Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Leo-Pekka Lyytikäinen
- Department of Clinical Chemistry, Fimlab Laboratories, Tampere University Hospital and University of Tampere School of Medicine, Tampere, Finland
| | - Ann-Kristin Petersen
- Institute of Genetic Epidemiology, Helmholtz Zentrum München, Neuherberg, Germany
| | - Jennifer Prescott
- Program in Molecular and Genetic Epidemiology, Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lisette Stolk
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
- Netherlands Consortium of Healthy Aging, Rotterdam, The Netherlands
| | - Liesbeth Vandenput
- Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Andrew R. Wood
- Genetics of Complex Traits, Peninsula Medical School, University of Exeter, Exeter, United Kingdom
| | - Wei Vivian Zhuang
- Department of Biostatistics, Boston University School of Public Health, Boston, Massachusetts, United States of America
| | - Aimo Ruokonen
- Institute of Diagnostics, University of Oulu, Oulu, Finland
| | | | - Anneli Pouta
- National Institute for Health and Welfare and Institute of Health Sciences, University of Oulu, Oulu, Finland
| | | | - Reiner Biffar
- Department of Prosthetic Dentistry, Gerostomatology, and Dental Materials, University of Greifswald, Greifswald, Germany
| | - Georg Brabant
- Experimental and Clinical Endocrinology, University of Lübeck, Lübeck, Germany
| | - David G. Cox
- Cancer Research Center of Lyon, INSERM U1052, Lyon, France
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College, London, United Kingdom
| | - Yuhui Chen
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Steven Cummings
- California Pacific Medical Center, San Francisco, California, United States of America
| | - Luigi Ferrucci
- Longitudinal Studies Section, Clinical Research Branch, National Institute on Aging, Baltimore, Maryland, United States of America
| | - Marc J. Gunter
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College, London, United Kingdom
| | - Susan E. Hankinson
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Biostatistics and Epidemiology, University of Massachusetts, Amherst, Massachusetts, United States of America
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Hannu Martikainen
- Department of Obstetrics and Gynecology, University Hospital of Oulu, Oulu, Finland
| | - Albert Hofman
- Netherlands Consortium of Healthy Aging, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands
| | - Georg Homuth
- Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
| | - Thomas Illig
- Research Unit of Molecular Epidemiology, Helmholtz Zentrum München, Neuherberg, Germany
- Hannover Unified Biobank, Hannover Medical School, Hannover, Germany
| | - John-Olov Jansson
- Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Andrew D. Johnson
- National Heart, Lung, and Blood Institute's The Framingham Heart Study, Framingham, Massachusetts, United States of America
| | - David Karasik
- Hebrew SeniorLife Institute for Aging Research and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Magnus Karlsson
- Clinical and Molecular Osteoporosis Research Unit, Department of Clinical Sciences and Department of Orthopaedics, Lund University, Malmö, Sweden
| | - Johannes Kettunen
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
- Department of Chronic Disease Prevention, National Institute for Health and Welfare, Helsinki, Finland
| | - Douglas P. Kiel
- Hebrew SeniorLife Institute for Aging Research and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Peter Kraft
- Program in Molecular and Genetic Epidemiology, Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Jingmin Liu
- Women's Health Initiative Clinical Coordinating Center, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Östen Ljunggren
- Department of Medical Sciences, University of Uppsala, Uppsala, Sweden
| | - Mattias Lorentzon
- Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Marcello Maggio
- Department of Internal Medicine and Biomedical Sciences, Section of Geriatrics, University of Parma, Parma, Italy
| | | | - Dan Mellström
- Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Iva Miljkovic
- University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Daniel Mirel
- Gene Environment Initiative, Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Boston, Massachusetts, United States of America
| | - Sarah Nelson
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Laure Morin Papunen
- Department of Obstetrics and Gynecology, University Hospital of Oulu, Oulu, Finland
| | - Petra H. M. Peeters
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Inga Prokopenko
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Oxford, United Kingdom
| | - Leslie Raffel
- Medical Genetics Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Martin Reincke
- Medizinische Klinik and Poliklinik IV, Ludwig-Maximilians University, Munich, Germany
| | - Alex P. Reiner
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Kathryn Rexrode
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Fernando Rivadeneira
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
- Netherlands Consortium of Healthy Aging, Rotterdam, The Netherlands
| | - Stephen M. Schwartz
- Cardiovascular Health Research Unit, Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - David Siscovick
- Cardiovascular Health Research Unit, Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - Nicole Soranzo
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
- Human Genetics, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Doris Stöckl
- Institute of Epidemiology II, Helmholtz Zentrum München, Neuherberg, Germany
- Department of Obstetrics and Gynaecology, Ludwig-Maximilians-University, Munich, Germany
| | - Shelley Tworoger
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - André G. Uitterlinden
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
- Netherlands Consortium of Healthy Aging, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands
| | - Carla H. van Gils
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ramachandran S. Vasan
- Section of Preventive Medicine and Epidemiology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- National Heart, Lung, and Blood Institute's The Framingham Heart Study, Framingham, Massachusetts, United States of America
| | - H.-Erich Wichmann
- Institute of Epidemiology I, Helmholtz Zentrum München, Neuherberg, Germany
- Institute of Medical Informatics, Biometry, and Epidemiology, Ludwig-Maximilians-Universität, Munich, Germany
- Klinikum Großhadern, Munich, Germany
| | - Guangju Zhai
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
- Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Shalender Bhasin
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Martin Bidlingmaier
- Medizinische Klinik and Poliklinik IV, Ludwig-Maximilians University, Munich, Germany
| | - Stephen J. Chanock
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Immaculata De Vivo
- Program in Molecular and Genetic Epidemiology, Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Tamara B. Harris
- Laboratory of Epidemiology, Demography, and Biometry, National Institute on Aging, Bethesda, Maryland, United States of America
| | - David J. Hunter
- Program in Molecular and Genetic Epidemiology, Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mika Kähönen
- Department of Clinical Physiology, Tampere University Hospital and University of Tampere School of Medicine, Tampere, Finland
| | - Simin Liu
- Program on Genomics and Nutrition, Department of Epidemiology, University of California Los Angeles, Los Angeles, California, United States of America
| | - Pamela Ouyang
- Division of Cardiology, Johns Hopkins Bayview Medical Center, Baltimore, Maryland, United States of America
| | - Tim D. Spector
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Yvonne T. van der Schouw
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Jorma Viikari
- Department of Medicine, Turku University Hospital and University of Turku, Turku, Finland
| | - Henri Wallaschofski
- Institute for Clinical Chemistry and Laboratory Medicine, University Medicine, Ernst-Moritz-Arndt University of Greifswald, Greifswald, Germany
| | - Mark I. McCarthy
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom
- Oxford NIHR Biomedical Research Centre, Churchill Hospital, Oxford, United Kingdom
| | - Timothy M. Frayling
- Genetics of Complex Traits, Peninsula Medical School, University of Exeter, Exeter, United Kingdom
| | - Anna Murray
- Genetics of Complex Traits, Peninsula Medical School, University of Exeter, Exeter, United Kingdom
| | - Steve Franks
- Institute of Reproductive and Developmental Biology, Imperial College London, London, United Kingdom
| | - Marjo-Riitta Järvelin
- Department of Biostatistics and Epidemiology, School of Public Health, MRC-HPA Centre for Environment and Health, Faculty of Medicine, Imperial College London, London, United Kingdom
- Institute of Health Sciences, University of Oulu, Oulu, Finland
- Biocenter Oulu, University of Oulu, Oulu, Finland
- National Institute of Health and Welfare, University of Oulu, Oulu, Finland
| | - Frank H. de Jong
- Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - Olli Raitakari
- Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital and Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku, Finland
| | - Alexander Teumer
- Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
| | - Claes Ohlsson
- Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Joanne M. Murabito
- National Heart, Lung, and Blood Institute's The Framingham Heart Study, Framingham, Massachusetts, United States of America
- Section of General Internal Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - John R. B. Perry
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
- Genetics of Complex Traits, Peninsula Medical School, University of Exeter, Exeter, United Kingdom
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Spuch C, Ortolano S, Navarro C. LRP-1 and LRP-2 receptors function in the membrane neuron. Trafficking mechanisms and proteolytic processing in Alzheimer's disease. Front Physiol 2012; 3:269. [PMID: 22934024 PMCID: PMC3429044 DOI: 10.3389/fphys.2012.00269] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 06/26/2012] [Indexed: 11/13/2022] Open
Abstract
Low density lipoprotein receptor-related protein (LRP) belongs to the low-density lipoprotein receptor family, generally recognized as cell surface endocytic receptors, which bind and internalize extracellular ligands for degradation in lysosomes. Neurons require cholesterol to function and keep the membrane rafts stable. Cholesterol uptake into the neuron is carried out by ApoE via LRPs receptors on the cell surface. In neurons the most important are LRP-1 and LRP-2, even it is thought that a causal factor in Alzheimer's disease (AD) is the malfunction of this process which cause impairment intracellular signaling as well as storage and/or release of nutrients and toxic compounds. Both receptors are multifunctional cell surface receptors that are widely expressed in several tissues including neurons and astrocytes. LRPs are constituted by an intracellular (ICD) and extracellular domain (ECD). Through its ECD, LRPs bind at least 40 different ligands ranging from lipoprotein and protease inhibitor complex to growth factors and extracellular matrix proteins. These receptors has also been shown to interact with scaffolding and signaling proteins via its ICD in a phosphorylation-dependent manner and to function as a co-receptor partnering with other cell surface or integral membrane proteins. Thus, LRPs are implicated in two major physiological processes: endocytosis and regulation of signaling pathways, which are both involved in diverse biological roles including lipid metabolism, cell growth processes, degradation of proteases, and tissue invasion. Interestingly, LRPs were also localized in neurons in different stages, suggesting that both receptors could be implicated in signal transduction during embryonic development, neuronal outgrowth or in the pathogenesis of AD.
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Affiliation(s)
- Carlos Spuch
- Department of Pathology and Neuropathology, University Hospital of VigoVigo, Spain
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153
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Sanchez WY, de Veer SJ, Swedberg JE, Hong EJ, Reid JC, Walsh TP, Hooper JD, Hammond GL, Clements JA, Harris JM. Selective cleavage of human sex hormone-binding globulin by kallikrein-related peptidases and effects on androgen action in LNCaP prostate cancer cells. Endocrinology 2012; 153:3179-89. [PMID: 22547569 DOI: 10.1210/en.2012-1011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Stimulation of the androgen receptor via bioavailable androgens, including testosterone and testosterone metabolites, is a key driver of prostate development and the early stages of prostate cancer. Androgens are hydrophobic and as such require carrier proteins, including sex hormone-binding globulin (SHBG), to enable efficient distribution from sites of biosynthesis to target tissues. The similarly hydrophobic corticosteroids also require a carrier protein whose affinity for steroid is modulated by proteolysis. However, proteolytic mechanisms regulating the SHBG/androgen complex have not been reported. Here, we show that the cancer-associated serine proteases, kallikrein-related peptidase (KLK)4 and KLK14, bind strongly to SHBG in glutathione S-transferase interaction analyses. Further, we demonstrate that active KLK4 and KLK14 cleave human SHBG at unique sites and in an androgen-dependent manner. KLK4 separated androgen-free SHBG into its two laminin G-like (LG) domains that were subsequently proteolytically stable even after prolonged digestion, whereas a catalytically equivalent amount of KLK14 reduced SHBG to small peptide fragments over the same period. Conversely, proteolysis of 5α-dihydrotestosterone (DHT)-bound SHBG was similar for both KLKs and left the steroid binding LG4 domain intact. Characterization of this proteolysis fragment by [(3)H]-labeled DHT binding assays revealed that it retained identical affinity for androgen compared with full-length SHBG (dissociation constant = 1.92 nM). Consistent with this, both full-length SHBG and SHBG-LG4 significantly increased DHT-mediated transcriptional activity of the androgen receptor compared with DHT delivered without carrier protein. Collectively, these data provide the first evidence that SHBG is a target for proteolysis and demonstrate that a stable fragment derived from proteolysis of steroid-bound SHBG retains binding function in vitro.
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Affiliation(s)
- Washington Y Sanchez
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, Queensland 4059, Australia
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154
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Finigan J, Gossiel F, Glüer CC, Felsenberg D, Reid DM, Roux C, Eastell R. Endogenous estradiol and the risk of incident fracture in postmenopausal women: the OPUS study. Calcif Tissue Int 2012; 91:59-68. [PMID: 22644322 DOI: 10.1007/s00223-012-9611-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 05/02/2012] [Indexed: 11/30/2022]
Abstract
Some, but not all, studies have found that low endogenous estradiol levels in postmenopausal women are predictive of fractures. The aim of this study was to examine the roles of endogenous estradiol (E(2)), sex hormone binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEAS) in the prediction of incident vertebral and nonvertebral fractures. The study subjects were 797 postmenopausal women from the population-based OPUS (Osteoporosis and Ultrasound Study) study. Spine radiographs and dual-energy X-ray absorptiometry scans were obtained for all subjects at baseline and 6-year follow-up. Nonfasting blood samples were taken at baseline for E(2), SHBG, DHEAS, and bone turnover markers. Incident nonvertebral fractures were self-reported and verified; vertebral fractures were diagnosed at a single center from spinal radiographs. Medical and lifestyle data were obtained by questionnaire at each visit. Thirty-nine subjects had an incident vertebral fracture and 119 a nonvertebral fracture. Estradiol in the lowest quartile predicted vertebral fracture independent of confounders including age, body mass index, bone mineral density, bone turnover, fracture history, and use of antiresorptive therapy, with an OR of 2.97 (95 % confidence interval [CI] 1.52-5.82) by logistic regression. A calculated free estradiol index was not a stronger predictor than total E(2). Higher SHBG predicted vertebral fracture independently of age and body mass index, but not independently of E(2), bone mineral density, or prevalent fracture. Low DHEAS did not predict vertebral fracture. Nonvertebral fractures were not predicted by any of E(2), SHBG, or DHEAS, either in univariate or multivariate analyses. These findings suggest that there may be mechanistic differences in the protective effect of E(2) at vertebral compared with nonvertebral sites.
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Affiliation(s)
- J Finigan
- Academic Unit of Bone Metabolism, University of Sheffield, Sheffield, UK.
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155
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Chun RF. New perspectives on the vitamin D binding protein. Cell Biochem Funct 2012; 30:445-56. [DOI: 10.1002/cbf.2835] [Citation(s) in RCA: 176] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 03/09/2012] [Accepted: 03/28/2012] [Indexed: 12/23/2022]
Affiliation(s)
- Rene F. Chun
- UCLA/Orthopaedic Hospital; Department of Orthopaedic Surgery, Orthopaedic Hospital Research Center, David Geffen School of Medicine at UCLA; Los Angeles; California; USA
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156
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Go GW, Mani A. Low-density lipoprotein receptor (LDLR) family orchestrates cholesterol homeostasis. YALE JOURNAL OF BIOLOGY AND MEDICINE 2012. [PMID: 22461740 DOI: 10.1002/9780470015902.a0006138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The LDLR family of proteins is involved in lipoproteins trafficking. While the role of LDLR in cardiovascular disease has been widely studied, only recently the role of other members of the LDLR proteins in lipoprotein homeostasis and atherosclerosis has emerged. LDLR, VLDLR, and LRPs bind and internalize apoE- and apoB-containing lipoprotein, including LDL and VLDL, and regulate their cellular uptake. LRP6 is a unique member of this family for its function as a co-receptor for Wnt signal transduction. The work in our laboratory has shown that LRP6 also plays a key role in lipoprotein and TG clearance, glucose homoeostasis, and atherosclerosis. The role of these receptor proteins in pathogenesis of diverse metabolic risk factors is emerging, rendering them targets of novel therapeutics for metabolic syndrome and atherosclerosis. This manuscript reviews the physiological role of the LDLR family of proteins and describes its involvement in pathogenesis of hyperlipidemia and atherosclerosis.
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Affiliation(s)
- Gwang-Woong Go
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
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Kolkhof P, Borden SA. Molecular pharmacology of the mineralocorticoid receptor: prospects for novel therapeutics. Mol Cell Endocrinol 2012; 350:310-7. [PMID: 21771637 DOI: 10.1016/j.mce.2011.06.025] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 06/21/2011] [Accepted: 06/24/2011] [Indexed: 11/23/2022]
Abstract
The blockade of mineralocorticoid receptors (MR) has been shown to be an invaluable therapy in heart failure and hypertension. To date, only two steroidal antimineralocorticoids, spironolactone (and its active metabolite canrenone) and eplerenone, have been approved, whereas novel non-steroidal compounds are in preclinical and early development. The careful investigation of the efficacy and tolerance of spironolactone in essential hypertension initially supported the idea that a more selective second generation of MR antagonists is desired for chronic treatment of cardiovascular diseases. More than 40 years went by between the approval of the first MR antagonist spironolactone and the market introduction of its sole successor, eplerenone. The molecular pharmacology of MR antagonists may be addressed at different levels. Available preclinical and clinical data of the two approved steroidal antimineralocorticoids allow a good comparison of potency and selectivity of MR antagonists and their pharmacokinetic properties. The search for novel generations of MR antagonists with the ultimate goal of a more tissue selective mode of action may require novel compounds that are differentiated with respect to the binding mode to the MR. Other factors that may contribute to tissue selectivity as e.g. the physicochemical properties of a drug and how they influence the resulting pharmacology in the context of tissue selective co-factor expression are even less well understood. In the following we will review these aspects and demonstrate that the molecular pharmacology of current MR antagonists is on the one hand far from well understood and, on the other hand, still offers room for improvements.
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Affiliation(s)
- Peter Kolkhof
- Cardiology Research, Department Heart Diseases, Global Drug Discovery, Bayer Healthcare Pharmaceuticals, Wuppertal, Germany
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158
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Bioavailable vitamin D is more tightly linked to mineral metabolism than total vitamin D in incident hemodialysis patients. Kidney Int 2012; 82:84-9. [PMID: 22398410 PMCID: PMC3376220 DOI: 10.1038/ki.2012.19] [Citation(s) in RCA: 162] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Prior studies showed conflicting results regarding the association between 25-hydroxyvitamin D (25(OH)D) levels and mineral metabolism in end-stage renal disease. In order to determine whether the bioavailable vitamin D (that fraction not bound to vitamin D binding protein) associates more strongly with measures of mineral metabolism than total levels, we identified 94 patients with previously measured 25(OH)D and 1,25-dihydroxyvitamin D (1,25(OH)2D) from a cohort of incident hemodialysis patients. Vitamin D binding protein was measured from stored serum samples. Bioavailable 25(OH)D and 1,25(OH)2D were determined using previously validated formulae. Associations with demographic factors and measures of mineral metabolism were examined. When compared with whites, black patients had lower levels of total, but not bioavailable, 25(OH)D. Bioavailable, but not total, 25(OH)D and 1,25(OH)2D were each significantly correlated with serum calcium. In univariate and multivariate regression analysis, only bioavailable 25(OH)D was significantly associated with parathyroid hormone levels. Hence, bioavailable vitamin D levels are better correlated with measures of mineral metabolism than total levels in patients on hemodialysis.
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159
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Liao CH, Li HY, Yu HJ, Chiang HS, Lin MS, Hua CH, Ma WY. Low serum sex hormone-binding globulin: marker of inflammation? Clin Chim Acta 2012; 413:803-7. [PMID: 22293276 DOI: 10.1016/j.cca.2012.01.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 01/14/2012] [Accepted: 01/18/2012] [Indexed: 01/17/2023]
Abstract
BACKGROUND Low sex hormone-binding globulin (SHBG) is associated with metabolic syndrome (MetS), but its relationship with inflammation is unclear. METHODS This cross-sectional study included 696 subjects (255 men, 235 pre-menopausal women, and 206 postmenopausal women). Body mass index, waist circumference, blood pressure, lipid profiles, plasma glucose, insulin, FSH, LH, total testosterone (TT), estradiol, SHBG, dehydroepiandrosterone sulfate (DHEA-S), and hs-CRP concentrations were measured. MetS was defined according to the updated National Cholesterol Education Program criteria with modification of waist circumference for Asians. RESULTS Serum hs-CRP and SHBG were negatively correlated in men (r=-0.29, p<0.001), pre-menopausal women (r=-0.38, p<0.001), and postmenopausal women (r=-0.27, p<0.001). In men, TT and hs-CRP showed a negative association (r=-0.25, p<0.001), but the association was attenuated after adjusting for SHBG (r=-0.14, p=0.039). Multivariate regression models showed that SHBG was independently associated with hs-CRP in men (r=-0.18, p=0.009), pre-menopausal women (r=-0.15, p=0.025), and postmenopausal women (r=-0.21, p=0.005), adjusted for age, MetS components, insulin resistance, low-density lipoprotein-cholesterol, and serum sex hormone levels. CONCLUSIONS Serum SHBG and hs-CRP concentrations were inversely correlated in men, pre-menoposal, and post-menopausal women independently.
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Affiliation(s)
- Chun-Hou Liao
- Division of Urology, Department of Surgery, College of Medicine, School of Medicine, Fu Jen Catholic University, Taipei, Taiwan
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160
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Beydoun MA, Ding EL, Beydoun HA, Tanaka T, Ferrucci L, Zonderman AB. Vitamin D receptor and megalin gene polymorphisms and their associations with longitudinal cognitive change in US adults. Am J Clin Nutr 2012; 95:163-78. [PMID: 22170372 PMCID: PMC3238459 DOI: 10.3945/ajcn.111.017137] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Vitamin D receptor (VDR) and the megalin gene polymorphism's link with longitudinal cognitive change remains unclear. OBJECTIVE The associations of single nucleotide polymorphisms (SNPs) for VDR [rs11568820 (CdX-2:T/C), rs1544410 (BsmI:G/A), rs7975232 (ApaI:A/C), rs731236 (TaqI:G/A)], and Megalin (rs3755166:G/A; rs2075252:C/T; rs4668123:C/T) genes with longitudinal cognitive performance changes were examined. DESIGN Data from 702 non-Hispanic white participants in the Baltimore Longitudinal Study of Aging were used. Longitudinal annual rates of cognitive change (LARCCs) between age 50 y and the individual mean follow-up age were predicted with linear mixed models by using all cognitive score time points (prediction I) or time points before dementia onset (prediction II). Latent class, haplotype, and ordinary least squares (OLS) regression analyses were conducted. RESULTS Among key findings, in OLS models with SNP latent classes as predictors for LARCCs, Megalin(2) [rs3755166(-)/rs2075252(TT)/rs4668123(T-)] compared with Megalin(1) [rs3755166(-)/rs2075252(CC)/rs4668123(-)] was associated with greater decline among men for verbal memory (prediction II). Significant sex differences were also found for SNP haplotype (SNPHAP). In women, VDR(1) [BsmI(G-)/ApaI(C-)/TaqI(A-); baT] was linked to a greater decline in category fluency (prediction I: β = -0.031, P = 0.012). The Megalin(1) SNPHAP (GCC) was related to greater decline among women for verbal memory, immediate recall [California Verbal Learning Test (CVLT), List A; prediction II: β = -0.043, P = 0.006) but to slower decline among men for delayed recall (CVLT-DR: β > 0, P < 0.0125; both predictions). In women, the Megalin(2) SNPHAP (ACC) was associated with slower decline in category fluency (prediction II: β = +0.026, P = 0.005). Another finding was that Megalin SNP rs3755166:G/A was associated with greater decline in global cognition in both sexes combined and in verbal memory in men. CONCLUSION Sex-specific VDR and Megalin gene variations can modify age-related cognitive decline among US adults.
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Affiliation(s)
- May A Beydoun
- National Institute on Aging, Intramural Research Program, NIH, Baltimore, MD, USA.
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161
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Le TN, Nestler JE, Strauss JF, Wickham EP. Sex hormone-binding globulin and type 2 diabetes mellitus. Trends Endocrinol Metab 2012; 23:32-40. [PMID: 22047952 PMCID: PMC3351377 DOI: 10.1016/j.tem.2011.09.005] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 09/12/2011] [Accepted: 09/26/2011] [Indexed: 12/27/2022]
Abstract
Sex hormone-binding globulin (SHBG) has emerged as one of the multiple genetic and environmental factors that potentially contribute to the pathophysiology of type 2 diabetes mellitus (T2DM). In addition to epidemiologic studies demonstrating a consistent relationship between decreased levels of serum SHBG and incident T2DM, recent genetic studies also reveal that transmission of specific polymorphisms in the SHBG gene influence the risk of T2DM. At the molecular level, the multiple interactions between SHBG and its receptors in various target tissues suggest physiologic roles for SHBG that are more complex than the simple transport of sex hormones in serum. Taken together, these data provide support for an expanded role of SHBG in the pathophysiology of insulin resistance and T2DM.
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Affiliation(s)
- Trang N. Le
- Department of Pediatrics, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - John E. Nestler
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
- Institute for Women’s Health, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Jerome F. Strauss
- Institute for Women’s Health, Virginia Commonwealth University, Richmond, VA 23298, USA
- Department of Obstetrics and Gynecology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Edmond P. Wickham
- Department of Pediatrics, Virginia Commonwealth University, Richmond, VA 23298, USA
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
- Corresponding Author: Edmond P. Wickham III, MD, Division of Endocrinology and Metabolism, Virginia Commonwealth University, P.O. Box 980111, Richmond, VA 23298-0111, Telephone: (804) 828-9696; Fax: (804) 828-8389,
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162
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Sex hormones, insulin resistance, and diabetes mellitus among men with or at risk for HIV infection. J Acquir Immune Defic Syndr 2011; 58:173-80. [PMID: 21705912 DOI: 10.1097/qai.0b013e3182278c09] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To examine the relationship of free testosterone (FT) and sex hormone-binding globulin (SHBG) with insulin resistance and diabetes mellitus (DM) in HIV disease. DESIGN Cross-sectional analysis from 322 HIV-uninfected and 534 HIV-infected men in the Multicenter AIDS Cohort Study. METHODS : The main outcomes were DM and homeostasis model assessment-insulin resistance (HOMA-IR). DM was defined as fasting serum glucose ≥126 or self-reported DM and use of DM medications. HOMA-IR was calculated from fasting serum glucose and fasting insulin. RESULTS Compared with HIV-uninfected men in our sample, HIV-infected men were younger, with lower body mass index, and more often black. HIV-infected men had lower FT (P < 0.001) and higher SHBG (P < 0.0001). The adjusted odds ratio for DM was 1.98 (95% confidence interval: 1.04 to 3.78); mean adjusted log HOMA-IR was 0.21 units higher in HIV-infected men (P < 0.0001). Log SHBG, but not log FT, was associated with DM (odds ratio = 0.44, 95% confidence interval: 0.25 to 0.80) in both groups. Log FT and log SHBG were inversely related to insulin resistance (P < 0.05 for both) independent of HIV. CONCLUSIONS Compared with HIV-uninfected men, HIV-infected men had lower FT, higher SHBG, and more insulin resistance and DM. Lower FT and lower SHBG were associated with insulin resistance regardless of HIV serostatus. This suggests that sex hormones play a role in the pathogenesis of glucose abnormalities among HIV-infected men.
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163
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Walther DJ, Stahlberg S, Vowinckel J. Novel roles for biogenic monoamines: from monoamines in transglutaminase-mediated post-translational protein modification to monoaminylation deregulation diseases. FEBS J 2011; 278:4740-55. [DOI: 10.1111/j.1742-4658.2011.08347.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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164
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Bhasin S, Jasjua GK, Pencina M, D'Agostino R, Coviello AD, Vasan RS, Travison TG. Sex hormone-binding globulin, but not testosterone, is associated prospectively and independently with incident metabolic syndrome in men: the framingham heart study. Diabetes Care 2011; 34:2464-70. [PMID: 21926281 PMCID: PMC3198304 DOI: 10.2337/dc11-0888] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The association between total testosterone and metabolic syndrome has prompted speculation that low testosterone contributes to the pathophysiology of metabolic syndrome in men. We determined whether testosterone or sex hormone-binding globulin (SHBG) is independently associated with the risk of metabolic syndrome. RESEARCH DESIGN AND METHODS Cross-sectional relationships of hormone levels with metabolic syndrome were assessed in a sample of men in generation 2 of the Framingham Heart Study (FHS) who did not receive testosterone or androgen-deprivation therapy (n = 1,625) and confirmed in a validation sample of men in FHS generation 3 (n = 1,912). Hormone levels in generation 2 examination 7 were related prospectively to incident metabolic syndrome 6.6 years later at examination 8. Testosterone was measured using liquid chromatography-tandem mass spectrometry, SHBG was measured by immunofluorometric assay, and free testosterone was calculated. Metabolic syndrome was defined using the National Cholesterol Education Program Adult Treatment Panel III criteria. RESULTS Cross-sectionally, testosterone and SHBG were more strongly associated with metabolic syndrome than free testosterone in the training sample. SHBG, but not testosterone or free testosterone, was significantly associated with metabolic syndrome after adjusting for age, smoking, BMI, and insulin sensitivity (homeostasis model assessment of insulin resistance [HOMA-IR]). These findings were confirmed in a validation sample. Longitudinally, SHBG at examination 7, but not testosterone or free testosterone, was associated with incident metabolic syndrome at examination 8 after adjusting for age, smoking, BMI, and HOMA-IR. Multivariable analyses suggested that age, BMI, and insulin sensitivity independently affect SHBG and testosterone levels and the risk of metabolic syndrome and its components. CONCLUSIONS SHBG, but not testosterone, is independently associated with the risk of metabolic syndrome. These data do not reveal an independent prospective relationship between testosterone and metabolic syndrome in men.
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Affiliation(s)
- Shalender Bhasin
- Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston, MA, USA.
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165
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Coviello AD, Zhuang WV, Lunetta KL, Bhasin S, Ulloor J, Zhang A, Karasik D, Kiel DP, Vasan RS, Murabito JM. Circulating testosterone and SHBG concentrations are heritable in women: the Framingham Heart Study. J Clin Endocrinol Metab 2011; 96:E1491-5. [PMID: 21752884 PMCID: PMC3167671 DOI: 10.1210/jc.2011-0050] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Many factors influence the concentration of circulating testosterone and its primary binding protein, SHBG. However, little is known about the genetic contribution to their circulating concentrations in women, and their heritability in women is not well established. OBJECTIVE Our objective was to estimate the heritability of circulating total testosterone (TT), free testosterone (FT), and SHBG in women in families from the Framingham Heart Study. METHODS Women in the Framingham Heart Study who were not pregnant, had not undergone bilateral oophorectomy, and were not using exogenous hormones were eligible for this investigation. TT was measured using liquid chromatography tandem mass spectrometry and SHBG using an immunofluorometric assay (Delfia-Wallac), and FT was calculated. Heritability estimates were calculated using variance-components methods in Sequential Oligogenic Linkage Analysis Routines (SOLAR) and were adjusted for age, age(2), body mass index (BMI), BMI(2), diabetes, smoking, and menopausal status. Bivariate analyses were done to assess genetic correlation between TT, FT, and SHBG. RESULTS A total of 2685 women were studied including 868 sister pairs and 688 mother-daughter pairs. Multivariable adjusted heritability estimates were 0.26 ± 0.05 for FT, 0.26 ± 0.05 for TT, and 0.56 ± 0.05 for SHBG (P < 1.0 × 10(-7) for all). TT was genetically correlated with SHBG [genetic correlation coefficient (ρG) = 0.31 ± 0.10] and FT (ρG = 0.54 ± 0.09), whereas SHBG was inversely correlated with FT (ρG = -0.60 ± 0.08). CONCLUSION Circulating TT, FT, and SHBG concentrations in women are significantly heritable, underscoring the importance of further work to identify the specific genes that contribute significantly to variation in sex steroid concentrations in women. The strong shared genetic component among pairs of TT, FT, and SHBG concentrations suggests potential pleiotropic effects for some of the underlying genes.
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Affiliation(s)
- A D Coviello
- Sections of Preventive Medicine and Epidemiology, Department of Medicine, Boston University School of Medicine, Boston University School of Public Health, Boston, Massachusetts 02118, USA.
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166
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Porola P, Straub RH, Virkki LM, Konttinen YT, Nordström DC. Failure of oral DHEA treatment to increase local salivary androgen outputs of female patients with Sjögren's syndrome. Scand J Rheumatol 2011; 40:387-90. [DOI: 10.3109/03009742.2011.580000] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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167
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Strotmann J, Breer H. Internalization of odorant-binding proteins into the mouse olfactory epithelium. Histochem Cell Biol 2011; 136:357-69. [PMID: 21818577 DOI: 10.1007/s00418-011-0850-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2011] [Indexed: 10/17/2022]
Abstract
The detection of odorants in vertebrates is mediated by chemosensory neurons that reside in the olfactory epithelium of the nose. In land-living species, the hydrophobic odorous compounds inhaled by the airstream are dissolved in the nasal mucus by means of specialized globular proteins, the odorant-binding proteins (OBPs). To assure the responsiveness to odors of each inhalation, a rapid removal of odorants from the microenvironment of the receptor is essential. In order to follow the fate of OBP/odorant complexes, a recombinant OBP was fluorescently labeled, loaded with odorous compounds, and applied to the nose of a mouse. Very quickly, labeled OBP appeared inside the sustentacular cells of the epithelium. This uptake occurred only when the OBP was loaded with appropriate odorant compounds. A search for candidate transporters that could mediate such an uptake process led to the identification of the low density lipoprotein receptor Lrp2/Megalin. In the olfactory epithelium, megalin was found to be specifically expressed in sustentacular cells and the Megalin protein was located in their microvilli. In vitro studies using a cell line that expresses megalin revealed a rapid internalization of OBP/odorant complexes into lysosomes. The uptake was blocked by a Megalin inhibitor, as was the internalization of OBPs into the sustentacular cells of the olfactory epithelium. The results suggest that a Megalin-mediated internalization of OBP/odorant complexes into the sustentacular cells may represent an important mechanism for a rapid and local clearance of odorants.
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Affiliation(s)
- Jörg Strotmann
- Institute of Physiology, University of Hohenheim, Stuttgart, Germany.
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168
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Pöllänen E, Sipilä S, Alen M, Ronkainen PHA, Ankarberg-Lindgren C, Puolakka J, Suominen H, Hämäläinen E, Turpeinen U, Konttinen YT, Kovanen V. Differential influence of peripheral and systemic sex steroids on skeletal muscle quality in pre- and postmenopausal women. Aging Cell 2011; 10:650-60. [PMID: 21388496 DOI: 10.1111/j.1474-9726.2011.00701.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Aging is associated with gradual decline of skeletal muscle strength and mass often leading to diminished muscle quality. This phenomenon is known as sarcopenia and affects about 30% of the over 60-year-old population. Androgens act as anabolic agents regulating muscle mass and improving muscle performance. The role of female sex steroids as well as the ability of skeletal muscle tissue to locally produce sex steroids has been less extensively studied. We show that despite the extensive systemic deficit of sex steroid hormones in postmenopausal compared to premenopausal women, the hormone content of skeletal muscle does not follow the same trend. In contrast to the systemic levels, muscle tissue of post- and premenopausal women had similar concentrations of dehydroepiandrosterone and androstenedione, while the concentrations of estradiol and testosterone were significantly higher in muscle of the postmenopausal women. The presence of steroidogenetic enzymes in muscle tissue indicates that the elevated postmenopausal steroid levels in skeletal muscle are because of local steroidogenesis. The circulating sex steroids were associated with better muscle quality while the muscle concentrations reflected the amount of infiltrated fat within muscle tissue. We conclude that systemically delivered and peripherally produced sex steroids have distinct roles in the regulation of neuromuscular characteristics during aging.
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Affiliation(s)
- Eija Pöllänen
- Gerontology Research Center, Department of Health Sciences, University of Jyväskylä, FIN-40014 Jyväskylä, Finland
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169
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Tanimura A, Yamada F, Saito A, Ito M, Kimura T, Anzai N, Horie D, Yamamoto H, Miyamoto KI, Taketani Y, Takeda E. Analysis of different complexes of type IIa sodium-dependent phosphate transporter in rat renal cortex using blue-native polyacrylamide gel electrophoresis. THE JOURNAL OF MEDICAL INVESTIGATION 2011; 58:140-7. [PMID: 21372499 DOI: 10.2152/jmi.58.140] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Type IIa sodium-dependent phosphate transporter (NaPi-IIa) can be localized in the apical plasma membrane of renal proximal tubule to carry out a rate-limiting step of phosphate reabsorption. For the apical localization, NaPi-IIa is required to form a macromolecular complex with some adaptor proteins such as Na(+)/H(+) exchanger regulatory factor 1 (NHERF-1) and ezrin. However, the detail of macromolecular complex containing NaPi-IIa in the apical membrane of the renal proximal tubular cells has not been clarified. In this study, we identified at least four different complexes (220, 480, 920, 1,100 kDa) containing NaPi-IIa by using blue-native polyacrylamide gel electrophoresis. Interestingly, LC-MS/MS analysis and immunoprecipitation analysis reveal that megalin is a component of larger complexes (920 and 1,100 kDa). In addition, NaPi-IIa can be heterogeneously co-localized with ezrin and megalin on the apical membrane of renal proximal tubuler cells by fluorescence microscopy analysis. These results suggest that NaPi-IIa can form some different complexes on the apical plasma membrane of renal proximal tubular cells.
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Affiliation(s)
- Ayako Tanimura
- Department of Clinical Nutrition, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Japan
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170
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Acconcia F, Marino M. The Effects of 17β-estradiol in Cancer are Mediated by Estrogen Receptor Signaling at the Plasma Membrane. Front Physiol 2011; 2:30. [PMID: 21747767 PMCID: PMC3129035 DOI: 10.3389/fphys.2011.00030] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 06/17/2011] [Indexed: 12/16/2022] Open
Abstract
Two different isoforms of the estrogen receptors (i.e., ERα and ERβ) mediate pleiotropic 17β-estradiol (E2)-induced cellular effects. The ERs are principally localized in the nucleus where they act by globally modifying the expression of the E2-target genes. The premise that E2 effects are exclusively mediated through the nuclear localized ERs has been rendered obsolete by research over the last 15 years demonstrating that ERα and ERβ proteins are also localized at the plasma membranes and in other extra-nuclear organelles. The E2 modulation of cancer cell proliferation represents a good example of the impact of membrane-initiated signals on E2 effects. In fact, E2 via ERα elicits rapid signals driving cancer cells to proliferation (e.g., in breast cancer cells), while E2-induced ERβ rapid signaling inhibits proliferation (e.g., in colon cancer cells). In this review we provide with an overview of the complex system of E2-induced signal transduction pathways, their impact on E2-induced cancer cell proliferation, and the participation of E2-induced membrane-initiated signals in tumor environment.
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Affiliation(s)
- Filippo Acconcia
- Cell Physiology Laboratory, Department of Biology, University Roma Tre Rome, Italy
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171
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Abstract
Sex hormone-binding globulin (SHBG) transports androgens and estrogens in blood and regulates their access to target tissues. Hepatic production of SHBG fluctuates throughout the life cycle and is influenced primarily by metabolic and hormonal factors. Genetic differences also contribute to interindividual variations in plasma SHBG levels. In addition to controlling the plasma distribution, metabolic clearance, and bioavailability of sex steroids, SHBG accumulates in the extravascular compartments of some tissues and in the cytoplasm of specific epithelial cells, where it exerts novel effects on androgen and estrogen action. In mammals, the gene-encoding SHBG is expressed primarily in the liver but also at low levels in other tissues, including the testis. In subprimate species, Shbg expression in Sertoli cells is under the control of follicle-stimulating hormone and produces the androgen-binding protein that influences androgen actions in the seminiferous tubules and epididymis. In humans, the SHBG gene is not expressed in Sertoli cells, but its expression in germ cells produces an SHBG isoform that accumulates in the acrosome. In fish, Shbg is produced by the liver but has a unique function in the gill as a portal for natural steroids and xenobiotics, including synthetic steroids. However, salmon have retained a second, poorly conserved Shbg gene that is expressed only in ovary, muscle, and gill and that likely exerts specialized functions in these tissues. The present review compares the production and functions of SHBG in different species and its diverse effects on reproduction.
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Affiliation(s)
- Geoffrey L Hammond
- Child & Family Research Institute and Department of Obstetrics & Gynecology, University of British Columbia, Vancouver, British Columbia, Canada.
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172
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Ho CKM, Beckett GJ. Late-onset male hypogonadism: clinical and laboratory evaluation. J Clin Pathol 2011; 64:459-65. [PMID: 21486896 DOI: 10.1136/jcp.2010.076968] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Late-onset male hypogonadism (LOH) is a clinical and biochemical syndrome associated with advancing age and characterised by low serum testosterone concentrations. An understanding of the physiology of androgens in the ageing man is essential for the appropriate diagnosis of LOH. Clinical assessment of androgen status relevant to clinical biochemists and chemical pathologists is outlined in this review. Laboratory investigations of androgen status in men are not without pitfalls and the authors highlight problems associated with measuring and calculating serum testosterone and its fractions, the interpretation of which can be problematic. Current clinical guidelines and recommendations regarding the diagnosis and monitoring of LOH are also summarised.
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Affiliation(s)
- Clement K M Ho
- Department of Biochemistry, Raigmore Hospital, Inverness, UK.
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173
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Enea C, Boisseau N, Fargeas-Gluck MA, Diaz V, Dugué B. Circulating androgens in women: exercise-induced changes. Sports Med 2011; 41:1-15. [PMID: 21142281 DOI: 10.2165/11536920-000000000-00000] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Physical exercise is known to strongly stimulate the endocrine system in both sexes. Among these hormones, androgens (e.g. testosterone, androstenedione, dehydroepiandrosterone) play key roles in the reproductive system, muscle growth and the prevention of bone loss. In female athletes, excessive physical exercise may lead to disorders, including delay in the onset of puberty, amenorrhoea and premature osteoporosis. The free and total fractions of circulating androgens vary in response to acute and chronic exercise/training (depending on the type), but the physiological role of these changes is not completely understood. Although it is commonly accepted that only the free fraction of steroids has a biological action, this hypothesis has recently been challenged. Indeed, a change in the total fraction of androgen concentration may have a significant impact on cells (inducing genomic or non-genomic signalling). The purpose of this review, therefore, is to visit the exercise-induced changes in androgen concentrations and emphasize their potential effects on female physiology. Despite some discrepancies in the published studies (generally due to differences in the types and intensities of the exercises studied, in the hormonal status of the group of women investigated and in the methods for androgen determination), exercise is globally able to induce an increase in circulating androgens. This can be observed after both resistance and endurance acute exercises. For chronic exercise/training, the picture is definitely less clear and there are even circumstances where exercise leads to a decrease of circulating androgens. We suggest that those changes have significant impact on female physiology and physical performance.
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174
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Schobert R, Seibt S, Effenberger-Neidnicht K, Underhill C, Biersack B, Hammond GL. (Arene)Cl₂Ru(II) complexes with N-coordinated estrogen and androgen isonicotinates: interaction with sex hormone binding globulin and anticancer activity. Steroids 2011; 76:393-9. [PMID: 21184767 DOI: 10.1016/j.steroids.2010.12.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 11/25/2010] [Accepted: 12/15/2010] [Indexed: 11/20/2022]
Abstract
(Arene)dichloridoruthenium(II) complexes with N-coordinated isonicotinates of androgens (6) and estrogens (9) were prepared and tested for affinity to the estrogen receptor (ERα) and sex hormone binding globulin (SHBG), as well as for cytotoxicity in cancer cells. None of the new complexes bound noticeably to the ER and most of them also bound less strongly to SHBG than the corresponding unmetallated steroids 7. In MTT assays the Ru(p-cymene) complexes 9 of 2-substituted estrones were equally or even more cytotoxic than the metal-free steroids against hormone-dependent (MCF-7 breast and KB-V1 cervix carcinomas) and hormone-independent (518A2 melanoma) cells. The addition of external SHBG to MTT assays lowered the cytotoxicities of the complexes 9 and distinctly more so those of some steroids 7, probably by the way of sequestration and reduction of the cellular uptake. In the absence of SHBG the estrogen complexes 9 were internalized by 518A2 melanoma cells and ruthenated their DNA as quantified by ICP-OES. They also ruthenated salmon sperm DNA but did not change the topology of plasmid DNA in EMSA experiments. In addition, the Ru(p-cymene) complex of 2-ethoxyestrone (9c) was shown to reduce the motility of 518A2 melanoma cells in a wound-healing assay.
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Affiliation(s)
- Rainer Schobert
- Organic Chemistry Laboratory, University of Bayreuth, Universitaetsstrasse 30, D-95440 Bayreuth, Germany.
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175
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Dieckmann M, Dietrich MF, Herz J. Lipoprotein receptors--an evolutionarily ancient multifunctional receptor family. Biol Chem 2011; 391:1341-63. [PMID: 20868222 DOI: 10.1515/bc.2010.129] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The evolutionarily ancient low-density lipoprotein (LDL) receptor gene family represents a class of widely expressed cell surface receptors. Since the dawn of the first primitive multicellular organisms, several structurally and functionally distinct families of lipoprotein receptors have evolved. In accordance with the now obsolete 'one-gene-one-function' hypothesis, these cell surface receptors were originally perceived as mere transporters of lipoproteins, lipids, and nutrients or as scavenger receptors, which remove other kinds of macromolecules, such as proteases and protease inhibitors from the extracellular environment and the cell surface. This picture has since undergone a fundamental change. Experimental evidence has replaced the perception that these receptors serve merely as cargo transporters. Instead it is now clear that the transport of macromolecules is inseparably intertwined with the molecular machinery by which cells communicate with each other. Lipoprotein receptors are essentially sensors of the extracellular environment that participate in a wide range of physiological processes by physically interacting and coevolving with primary signal transducers as co-regulators. Furthermore, lipoprotein receptors modulate cellular trafficking and localization of the amyloid precursor protein (APP) and the β-amyloid peptide (Aβ), suggesting a role in the pathogenesis of Alzheimer's disease. Moreover, compelling evidence shows that LDL receptor family members are involved in tumor development and progression.
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Affiliation(s)
- Marco Dieckmann
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9046, USA
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176
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Sorensen MV, Praetorius HA, Nykjaer A, Willnow T, Leipziger J. Impaired aldosterone responsiveness in corticosteroid binding globulin deficient mice. Acta Physiol (Oxf) 2011; 201:169-77. [PMID: 20969731 DOI: 10.1111/j.1748-1716.2010.02208.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM Corticosteroid binding globulin (CBG) is the high affinity plasma carrier protein for cortisol. It keeps the steroids inactive, prevents them from degradation and defines the amount of free hormone acting on target tissues. Previous findings have shown insufficient responsiveness of corticosterone in peripheral tissues in CBG⁻(/)⁻ mice despite elevated free plasma corticosterone. In the large intestine, glucocorticoids synergistically enhance the pro-absorptive effects of aldosterone. We therefore hypothesized that CBG⁻(/)⁻ mice have reduced responsiveness to aldosterone. METHODS We used CBG⁻(/)⁻ and CBG(+/+) mice to investigate distal colonic electrogenic Na(+) absorption. An Ussing chamber was used to quantify amiloride-sensitive Na(+) transport in distal colonic mucosa (ΔI(sc) (amil)) as a measure of the physiological effect of aldosterone. RESULTS No differences were observed in ΔI(sc) (amil) or aldosterone levels in animals on control diet. When Na(+) restricted, CBG(+/+) mice responded with a marked up-regulation of ΔI(sc) (amil) (25-fold). In CBG⁻(/)⁻ mice this up-regulation was greatly attenuated as seen in a markedly reduced amiloride-sensitive short circuit current (reduced by ∼50%), a reduced ability to lower faecal Na(+) excretion and a significantly attenuated up-regulation of the ENaC channel γ-subunit. Diet-induced increases of total plasma aldosterone were similar in both genotypes, but CBG⁻(/)⁻ mice had an increased free plasma aldosterone fraction. SUMMARY This study defines the functional hyporesponsiveness and aldosterone resistance in distal colon of CBG⁻(/)⁻ mice. This resistance occurs despite sufficient free corticosterone plasma level. Thus, steroid actions require an intrinsic but unknown function of CBG, which allows the sufficient supply of the hormone/s to the target tissue.
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Affiliation(s)
- M V Sorensen
- Department of Physiology and Biophysics, The Water and Salt Research Center, Aarhus University, Denmark
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177
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Kushnir MM, Rockwood AL, Roberts WL, Yue B, Bergquist J, Meikle AW. Liquid chromatography tandem mass spectrometry for analysis of steroids in clinical laboratories. Clin Biochem 2011; 44:77-88. [DOI: 10.1016/j.clinbiochem.2010.07.008] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 06/28/2010] [Accepted: 07/04/2010] [Indexed: 01/18/2023]
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178
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Steroid binding properties of the 2nd WHO International Standard for sex hormone-binding globulin. Clin Chem Lab Med 2011; 49:869-72. [DOI: 10.1515/cclm.2011.146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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179
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Hong EJ, Sahu B, Jänne OA, Hammond GL. Cytoplasmic accumulation of incompletely glycosylated SHBG enhances androgen action in proximal tubule epithelial cells. Mol Endocrinol 2010; 25:269-81. [PMID: 21193555 DOI: 10.1210/me.2010-0483] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Human sex hormone-binding globulin (SHBG) accumulates within the cytoplasm of epithelial cells lining the proximal convoluted tubules of mice expressing human SHBG transgenes. The main ligands of SHBG, testosterone and its metabolite, 5α-dihydrotestosterone (DHT), alter expression of androgen-responsive genes in the kidney. To determine how intracellular SHBG might influence androgen action, we used a mouse proximal convoluted tubule (PCT) cell line with characteristics of S1/S2 epithelial cells in which human SHBG accumulates. Western blotting revealed that SHBG extracted from PCT cells expressing a human SHBG cDNA (PCT-SHBG) is 5-8 kDa smaller than the SHBG secreted by these cells, due to incomplete N-glycosylation and absence of O-linked oligosaccharides. PCT-SHBG cells sequester [(3)H]DHT more effectively from culture medium than parental PCT cells, and the presence of SHBG accentuates androgen-dependent activation of a luciferase reporter gene, as well as the endogenous kidney androgen-regulated protein (Kap) gene. After androgen withdrawal, androgen-induced Kap mRNA levels in PCT-SHBG cells are maintained for more than 2 wk vs 2 d in parental PCT cells. Transcriptome profiling after testosterone or DHT pretreatments, followed by 3 d of steroid withdrawal, also demonstrated that intracellular SHBG enhances androgen-dependent stimulation (e.g. Adh7, Vcam1, Areg, Tnfaip2) or repression (e.g. Cldn2 and Osr2) of many other genes in PCT cells. In addition, nuclear localization of the androgen receptor is enhanced and retained longer after steroid withdrawal in PCT cells containing functional SHBG. Thus, intracellular SHBG accentuates the uptake of androgens and sustains androgens access to the androgen receptor, especially under conditions of limited androgen supply.
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Affiliation(s)
- Eui-Ju Hong
- Department of Obstetrics and Gynecology, University of British Columbia, Child and Family Research Institute, Vancouver, British Columbia, Canada
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180
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Konttinen YT, Stegaev V, Mackiewicz Z, Porola P, Hänninen A, Szodoray P. Salivary glands - "an unisex organ'? Oral Dis 2010; 16:577-85. [PMID: 20412448 DOI: 10.1111/j.1601-0825.2010.01669.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Usually no distinction is made between female and male salivary glands although cyclic changes of and ⁄ or differences in serum and salivary sex steroid concentrations characterize women and men. Moreover, sexual dimorphism is well recognized in salivary glands of rodents.Salivary glands contain estrogen and androgen receptors and are, according to modern high throughput technologies,subjected to gender differences not explainable by gene dose effects by the X chromosome alone. Because sex steroids are lipophilic, it is often thought that approximately 10% of them passively diffuse from plasma to saliva. Indeed, saliva can find use as sample material in sports medicine, pediatrics, veterinary medicine and behavioral sciences. Last but not least, humans and other primates are unique in that they have a reticular zone in their adrenal cortex, which produces dehydroepiandrosterone and androstendione pro-hormones. These are processed in peripheral tissues, not only in female breast and uterus and male prostate, but also in salivary glands by an intracrine enzymatic machinery to active 17b-estradiol,dihydrotestosterone and others, to satisfy and buffer against a constantly changing needs caused by circadian,menstrual, pregnancy and chronobiological hormonal changes in the systemic circulation. Female dominance of Sjögren's syndrome and certain forms of salivary gland cancer probably reflect these gender-based differences.
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Affiliation(s)
- Y T Konttinen
- Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland.
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181
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Mutation of megalin leads to urinary loss of selenoprotein P and selenium deficiency in serum, liver, kidneys and brain. Biochem J 2010; 431:103-11. [PMID: 20653565 DOI: 10.1042/bj20100779] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Distribution of selenium (Se) within the mammalian body is mediated by SePP (selenoprotein P), an Se-rich glycoprotein secreted by hepatocytes. Genetic and biochemical evidence indicate that the endocytic receptors ApoER2 (apolipoprotein E receptor 2) and megalin mediate tissue-specific SePP uptake. In the present study megalin-mutant mice were fed on diets containing adequate (0.15 p.p.m.) or low (0.08 p.p.m.) Se content and were analysed for tissue and plasma Se levels, cellular GPx (glutathione peroxidase) activities and protein expression patterns. Megalin-mutant mice displayed increased urinary Se loss, which correlated with SePP excretion in their urine. Accordingly, serum Se and SePP levels were significantly reduced in megalin-mutant mice, reaching marginal levels on the low-Se diet. Moreover, kidney Se content and expression of renal selenoproteins were accordingly reduced, as was SePP internalization along the proximal tubule epithelium. Although GPx4 expression was not altered in testis, Se and GPx activity in liver and brain were significantly reduced. When fed on a low-Se diet, megalin-mutant mice developed impaired movement co-ordination, but no astrogliosis. These findings suggest that megalin prevents urinary SePP loss and participates in brain Se/SePP uptake.
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182
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Correale J, Ysrraelit MC, Gaitán MI. Gender differences in 1,25 dihydroxyvitamin D3 immunomodulatory effects in multiple sclerosis patients and healthy subjects. THE JOURNAL OF IMMUNOLOGY 2010; 185:4948-58. [PMID: 20855882 DOI: 10.4049/jimmunol.1000588] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Vitamin D(3) is best known as a calcium homeostasis modulator; however, it also has immune-modulating potential. In this study, we demonstrated that immunomodulatory effects of vitamin D(3) are significantly stronger in females than in males in multiple sclerosis patients, as well as in healthy subjects. Inhibition of self-reactive T cell proliferation and reduction in IFN-γ- and IL-17-secreting cell numbers were considerably greater in females. Furthermore, the increase in IL-10-secreting and CD4(+)CD25(+)FoxP3(+) regulatory T cell numbers were also greater in females. In parallel with these findings, female subjects had fewer CYP24A1 transcripts encoding the 1,25-dihydroxyvitamin D(3)-inactivating enzyme, as well as greater binding and internalization of vitamin D(3)-binding protein, a transporter for vitamin D(3) and its metabolites. These gender-based disparities lead to the accumulation of vitamin D(3) and its metabolites in target cells from female subjects and result in a more potent anti-inflammatory effect. Interestingly, 17-β estradiol reproduced these effects on self-reactive T cells and macrophages from male subjects, suggesting a functional synergy between 1,25-dihydroxyvitamin D(3) and 17-β estradiol, mediated through estrogen receptor α. Collectively, these results demonstrate estrogen-promoted differences in vitamin D(3) metabolism, suggesting a greater protective effect of vitamin D(3)-based therapeutic strategies in women.
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Affiliation(s)
- Jorge Correale
- Department of Neurology, Raúl Carrea Institute for Neurological Research, Buenos Aires, Argentina.
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183
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Cauley JA, Ewing SK, Taylor BC, Fink HA, Ensrud KE, Bauer DC, Barrett-Connor E, Marshall L, Orwoll ES. Sex steroid hormones in older men: longitudinal associations with 4.5-year change in hip bone mineral density--the osteoporotic fractures in men study. J Clin Endocrinol Metab 2010; 95:4314-23. [PMID: 20554716 PMCID: PMC2936055 DOI: 10.1210/jc.2009-2635] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT There is limited information on the association between sex hormones and bone loss in older men. OBJECTIVE Our objective was to determine the longitudinal association between sex steroid hormones and bone mineral density (BMD). DESIGN AND SETTING We conducted a prospective study of 5995 men aged at least 65 yr old at six U.S. clinical centers. PARTICIPANTS Sex steroid hormones were measured in a random sample of 1602 men. After exclusions, 1238 men were included in cross-sectional analyses and 969 in longitudinal analyses. Baseline sex hormones were measured using liquid chromatography-mass spectrometry. Bioavailable (Bio) estradiol (BioE2) and testosterone (BioT) were calculated from mass action equations. SHBG was measured using chemiluminescent substrate. MAIN OUTCOME MEASURES BMD of the total hip, measured at baseline and once or twice afterward over 4.6 yr of follow-up, was evaluated. RESULTS The annualized percent change in hip BMD increased with decreasing BioE2 (P trend = 0.03). Men with the lowest BioE2 (<39.7 pmol/liter) compared with the highest BioE2 (> or =66.0 pmol/liter) experienced 38% faster rate of BMD loss (P < 0.05). There was no association between BioT and hip BMD loss. Men with lowest BioE2, lowest BioT, and highest SHBG experienced a 3-fold faster rate of BMD loss compared with men with higher levels (P = 0.02). A threshold effect of SHBG was observed; the rate of hip BMD loss increased in men with SHBG of 49-60 nM. CONCLUSIONS Low BioE2 and high SHBG levels were associated with lower BMD and faster hip BMD loss. The combination of low BioE2, low BioT, and high SHBG was associated with significantly faster rates of BMD loss.
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Affiliation(s)
- Jane A Cauley
- University of Pittsburgh, Department of Epidemiology, 130 DeSoto Street, Crabtree A524, Pittsburgh, Pennsylvania 15261, USA.
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184
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Ly LP, Sartorius G, Hull L, Leung A, Swerdloff RS, Wang C, Handelsman DJ. Accuracy of calculated free testosterone formulae in men. Clin Endocrinol (Oxf) 2010; 73:382-8. [PMID: 20346001 DOI: 10.1111/j.1365-2265.2010.03804.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND As reference laboratory methods for measuring free testosterone (FT) by equilibrium dialysis (ED) are laborious, costly and nonautomatable, FT levels are often calculated (cFT) rather than measured. However, the predictive accuracy of such estimates in routine use relative to laboratory measurements is not well defined. We provide a large-scale evaluation of the predictive accuracy for different FT formulae compared with laboratory ED measurement and an analysis of clinical factors that may influence accuracy. METHODS The accuracy of five different cFT formulae (two equilibrium binding, three empirical) based on immunoassays of total testosterone (TT) and SHBG was evaluated by comparing those estimates with FT measurement by ED in 2159 serum samples from men at a single research laboratory over several years. RESULTS cFT formulae show systematic discrepancies from the two equilibrium-binding formulae. One empirical formula overestimated FT relative to ED measurements, whereas two newer empirical cFT formulae were more concordant. These discrepancies persisted after correction for serum albumin and were not influenced by obesity, ethnicity or gonadal status. CONCLUSIONS Commonly used cFT formulae significantly overestimate FT relative to laboratory measurement by ED in male serum samples. The accuracy of the formulae is not influenced by correction for serum albumin, obesity, ethnicity or gonadal status. Such inaccuracy relative to the reference method renders some cFT estimates unreliable for evaluating androgen deficiency as recommended by clinical best practice guidelines.
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Affiliation(s)
- Lam P Ly
- Andrology Department, Concord Hospital, Sydney, NSW 2139, Australia
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185
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Kortylewicz ZP, Nearman J, Baranowska-Kortylewicz J. Radiolabeled 5-iodo-3'-O-(17beta-succinyl-5alpha-androstan-3-one)-2'-deoxyuridine and its 5'-monophosphate for imaging and therapy of androgen receptor-positive cancers: synthesis and biological evaluation. J Med Chem 2010; 52:5124-43. [PMID: 19653647 DOI: 10.1021/jm9005803] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High levels of androgen receptor (AR) are often indicative of recurrent, advanced, or metastatic cancers. These conditions are also characterized by a high proliferative fraction. 5-Radioiodo-3'-O-(17beta-succinyl-5alpha-androstan-3-one)-2'-deoxyuridine 8 and 5-radioiodo-3'-O-(17beta-succinyl-5alpha-androstan-3-one)-2'-deoxyuridin-5'-yl monophosphate 13 target AR. They are also degraded intracellularly to 5-radioiodo-2'-deoxyuridine 1 and its monophosphate 20, respectively, which can participate in the DNA synthesis. Both drugs were prepared at the no-carrier-added level. Precursors and methods are readily adaptable to radiolabeling with various radiohalides suitable for SPECT and PET imaging, as well as endoradiotherapy. In vitro and in vivo studies confirm the AR-dependent interactions. Both drugs bind to sex hormone binding globulin. This binding significantly improves their stability in serum. Biodistribution and imaging studies show preferential uptake and retention of 8 and 13 in ip xenografts of human ovarian adenocarcinoma cells NIH:OVCAR-3, which overexpress AR. When these drugs are administered at therapeutic dose levels, a significant tumor growth arrest is observed.
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Affiliation(s)
- Zbigniew P Kortylewicz
- Department of Radiation Oncology, J. Bruce Henriksen Cancer Research Laboratories, University of Nebraska Medical Center, 986850 Nebraska Medical Center, Omaha, Nebraska 68198-6850, USA.
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186
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Abstract
PURPOSE OF REVIEW To describe the relationship between testosterone levels and type 2 diabetes (T2D). RECENT FINDINGS Multiple epidemiological studies have shown that low testosterone levels are associated with and predict the future development of T2D and the metabolic syndrome. Although this relationship is confounded by the association of total testosterone with sex hormone-binding globulin, free testosterone remains associated with measures of insulin resistance and T2D in some, but not all studies. Although the link between low testosterone levels and insulin resistance is not solely a consequence of adiposity, current studies suggest that a substantial component is mediated through its association with body fat, in particular abdominal visceral adipose tissue. This testosterone-fat relationship is bi-directional, as both weight loss and testosterone therapy increase testosterone levels, reduce fat mass, and decrease insulin resistance. SUMMARY Low testosterone levels are very commonly found in men with T2D and are associated with aging and obesity. Whether testosterone treatment in men with T2D decreases insulin resistance above that attributable to its fat-reducing effect is currently unknown. Future studies should compare testosterone treatment with lifestyle changes (exercise and weight loss measures), and other insulin-sensitizing agents. Until further evidence is available, testosterone therapy outside clinical trials should be reserved for diabetic men with unequivocal hypogonadism.
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Affiliation(s)
- Mathis Grossmann
- Department of Medicine, Austin Health/Northern Health, University of Melbourne, Heidelberg, Victoria, Australia.
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187
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Krasnoff JB, Basaria S, Pencina MJ, Jasuja GK, Vasan RS, Ulloor J, Zhang A, Coviello A, Kelly-Hayes M, D'Agostino RB, Wolf PA, Bhasin S, Murabito JM. Free testosterone levels are associated with mobility limitation and physical performance in community-dwelling men: the Framingham Offspring Study. J Clin Endocrinol Metab 2010; 95:2790-9. [PMID: 20382680 PMCID: PMC2902069 DOI: 10.1210/jc.2009-2680] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Mobility limitation is associated with increased morbidity and mortality. The relationship between circulating testosterone and mobility limitation and physical performance is incompletely understood. OBJECTIVE Our objective was to examine cross-sectional and prospective relations between baseline sex hormones and mobility limitations and physical performance in community-dwelling older men. DESIGN, SETTING, AND PARTICIPANTS We conducted cross-sectional and longitudinal analyses of 1445 men (mean age 61.0 +/- 9.5 yr) who attended Framingham Offspring Study examinations 7 and 8 (mean 6.6 yr apart). Total testosterone (TT) was measured by liquid chromatography tandem mass spectrometry at examination 7. Cross-sectional and longitudinal analyses of mobility limitation and physical performance were performed with continuous (per SD) and dichotomized [low TT and free testosterone (FT) and high SHBG vs. normal] hormone levels. MAIN OUTCOME MEASURES Self-reported mobility limitation, subjective health, usual walking speed, and grip strength were assessed at examinations 7 and 8. Short physical performance battery was performed at examination 7. RESULTS Higher continuous FT was positively associated with short physical performance battery score (beta = 0.13; P = 0.008), usual walking speed (beta = 0.02; P = 0.048), and lower risk of poor subjective health [odds ratio (OR) = 0.72; P = 0.01]. In prospective analysis, 1 SD increase in baseline FT was associated with lower risk of developing mobility limitation (OR = 0.78; 95% confidence interval = 0.62-0.97) and progression of mobility limitation (OR = 0.75; 95% confidence interval = 0.60-0.93). Men with low baseline FT had 57% higher odds of reporting incident mobility limitation (P = 0.03) and 68% higher odds of worsening of mobility limitation (P = 0.007). CONCLUSIONS Lower levels of baseline FT are associated with a greater risk of incident or worsening mobility limitation in community-dwelling older men. Whether this risk can be reduced with testosterone therapy needs to be determined by randomized trials.
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Affiliation(s)
- Joanne B Krasnoff
- Boston University School of Medicine, Section of Endocrinology, Diabetes, and Nutrition, 670 Albany Street, Second Floor, Boston, Massachusetts 02118-2393, USA
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188
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Kushnir MM, Rockwood AL, Bergquist J. Liquid chromatography-tandem mass spectrometry applications in endocrinology. MASS SPECTROMETRY REVIEWS 2010; 29:480-502. [PMID: 19708015 DOI: 10.1002/mas.20264] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been recognized as a primary methodology for the accurate analysis of endogenous steroid hormones in biological samples. This review focuses on the use of LC-MS/MS in clinical laboratories to assist with the diagnosis of diverse groups of endocrine and metabolic diseases. Described analytical methods use on-line and off-line sample preparation and analytical derivatization to enhance analytical sensitivity, specificity, and clinical utility. Advantages of LC-MS/MS as an analytical technique include high specificity, possibility to simultaneously measure multiple analytes, and the ability to assess the specificity of the analysis in every sample. All described analytical methods were extensively validated, utilized in routine diagnostic practice, and were applied in a number of clinical and epidemiological studies, including a study of the steroidogenesis in ovarian follicles.
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Affiliation(s)
- Mark M Kushnir
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, UT 84108, USA.
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189
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Veldhuis JD, Keenan DM, Liu PY, Takahashi PY. Kinetics of removal of intravenous testosterone pulses in normal men. Eur J Endocrinol 2010; 162:787-94. [PMID: 20089549 PMCID: PMC2861557 DOI: 10.1530/eje-09-1085] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Testosterone is secreted into the bloodstream episodically, putatively distributing into total, bioavailable (bio) nonsex hormone-binding globulin (nonSHBG-bound), and free testosterone moieties. The kinetics of total, bio, and free testosterone pulses are unknown. Design Adrenal and gonadal steroidogenesis was blocked pharmacologically, glucocorticoid was replaced, and testosterone was infused in pulses in four distinct doses in 14 healthy men under two different paradigms (a total of 220 testosterone pulses). METHODS Testosterone kinetics were assessed by deconvolution analysis of total, free, bioavailable, SHBG-bound, and albumin-bound testosterone concentration-time profiles. RESULTS Independently of testosterone dose or paradigm, rapid-phase half-lives (min) of total, free, bioavailable, SHBG-bound, and albumin-bound testosterone were comparable at 1.4+/-0.22 min (grand mean+/-S.E.M. of geometric means). Slow-phase testosterone half-lives were highest for SHBG-bound testosterone (32 min) and total testosterone (27 min) with the former exceeding that of free testosterone (18 min), bioavailable testosterone (14 min), and albumin-bound testosterone (18 min; P<0.001). Collective outcomes indicate that i) the rapid phase of testosterone disappearance from point sampling in the circulation is not explained by testosterone dose; ii) SHBG-bound testosterone and total testosterone kinetics are prolonged; and iii) the half-lives of bioavailable, albumin-bound, and free testosterone are short. CONCLUSION A frequent-sampling strategy comprising an experimental hormone clamp, estimation of hormone concentrations as bound and free moieties, mimicry of physiological pulses, and deconvolution analysis may have utility in estimating the in vivo kinetics of other hormones, substrates, and metabolites.
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Affiliation(s)
- Johannes D Veldhuis
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, Minnesota 55905, USA.
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190
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Avvakumov GV, Cherkasov A, Muller YA, Hammond GL. Structural analyses of sex hormone-binding globulin reveal novel ligands and function. Mol Cell Endocrinol 2010; 316:13-23. [PMID: 19748550 DOI: 10.1016/j.mce.2009.09.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Revised: 09/04/2009] [Accepted: 09/04/2009] [Indexed: 01/31/2023]
Abstract
Plasma sex hormone-binding globulin (SHBG) regulates the access of androgens and estrogens to their target tissues and cell types. An SHBG homologue, known as the androgen-binding protein, is expressed in Sertoli cells of many mammalians, but testicular expression of human SHBG is restricted to germ cells. The primary structure of SHBG comprises tandem laminin G-like (LG) domains. The amino-terminal LG-domain includes the steroid-binding site and dimerization interface, and its tertiary structure, resolved in complex with natural and synthetic sex steroids, has revealed unanticipated mechanisms of steroid binding at the atomic level. This LG-domain interacts with fibulin-1D and fibulin-2 in a ligand-specific manner, and this is attributed to the unique way estrogens reside within the steroid-binding site, and the ordering of an otherwise flexible loop structure covering the entrance of the steroid-binding pocket. This mechanism enables estradiol to enhance the sequestration of plasma SHBG by the stroma of some tissues through binding to these extra-cellular matrix-associated proteins. The human SHBG amino-terminal LG-domain also contains several cation-binding sites, and occupancy of a zinc-binding site influences its affinity for estradiol. The complete quaternary structure of SHBG remains unresolved but structural predictions suggest that the carboxy-terminal LG-domains extend laterally from the dimerized amino-terminal LG-domains. The carboxy-terminal LG-domain contains two N-glycosylation sites, but their biological significance remains obscure. Knowledge of the SHBG tertiary structure has helped develop computational techniques based on the use of a "bench-mark data set" of steroid ligands, and created novel drug discovery and toxicology risk assessment platforms.
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Affiliation(s)
- George V Avvakumov
- Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada
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191
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Willnow TE, Nykjaer A. Cellular uptake of steroid carrier proteins--mechanisms and implications. Mol Cell Endocrinol 2010; 316:93-102. [PMID: 19646505 DOI: 10.1016/j.mce.2009.07.021] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 07/21/2009] [Accepted: 07/21/2009] [Indexed: 01/05/2023]
Abstract
Steroid hormones are believed to enter cells solely by free diffusion through the plasma membrane. However, recent studies suggest the existence of cellular uptake pathways for carrier-bound steroids. Similar to the clearance of cholesterol via lipoproteins, these pathways involve the recognition of carrier proteins by endocytic receptors on the surface of target cells, followed by internalization and cellular delivery of the bound sterols. Here, we discuss the emerging concept that steroid hormones can selectively enter steroidogenic tissues by receptor-mediated endocytosis, and we discuss the implications of these uptake pathways for steroid hormone metabolism and action in vivo.
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192
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Pugeat M, Nader N, Hogeveen K, Raverot G, Déchaud H, Grenot C. Sex hormone-binding globulin gene expression in the liver: drugs and the metabolic syndrome. Mol Cell Endocrinol 2010; 316:53-9. [PMID: 19786070 DOI: 10.1016/j.mce.2009.09.020] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 09/17/2009] [Accepted: 09/18/2009] [Indexed: 01/21/2023]
Abstract
Sex hormone-binding globulin (SHBG) is the main transport binding protein for sex steroid hormones in plasma and regulates their accessibility to target cells. Plasma SHBG is secreted by the liver under the control of hormones and nutritional factors. In the human hepatoma cell line (HepG2), thyroid and estrogenic hormones, and a variety of drugs including the antioestrogen tamoxifen, the phytoestrogen, genistein and mitotane (Op'DDD) increase SHBG production and SHBG gene promoter activity. In contrast, monosaccharides (glucose or fructose) effectively decrease SHBG expression by inducing lipogenesis, which reduces hepatic HNF-4alpha levels, a transcription factor that play a critical role in controlling the SHBG promoter. Interestingly, diminishing hepatic lipogenesis and free fatty acid liver biosynthesis also appear to be associated with the positive effects of thyroid hormones and PPARgamma antagonists on SHBG expression. This mechanism provides a biological explanation for why SHBG is a sensitive biomarker of insulin resistance and the metabolic syndrome, and why low plasma SHBG levels are a risk factor for developing hyperglycemia and type 2 diabetes, especially in women. These important advances in our knowledge of the regulation of SHBG expression in the liver open new approaches for identifying and preventing metabolic disorder-associated diseases early in life.
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Affiliation(s)
- Michel Pugeat
- Hospices Civils de Lyon, Fédération d'Endocrinologie, Groupement Hospitalier Est, Bron, France.
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193
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Malisch JL, Breuner CW. Steroid-binding proteins and free steroids in birds. Mol Cell Endocrinol 2010; 316:42-52. [PMID: 19786069 DOI: 10.1016/j.mce.2009.09.019] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 09/18/2009] [Accepted: 09/18/2009] [Indexed: 11/16/2022]
Abstract
Within the comparative literature, corticosteroid-binding globulin (CBG) has recently emerged as a potential modulator of the glucocorticoids-driven stress response. Many avian field studies include the measurement of CBG with the goal of making behavioral and ecological inferences. However, the field of stress physiology is divided on how to interpret the biological importance of the different states of circulating hormones. Here we review evidence for the biological relevance of each fraction of glucocorticoid hormone; the CBG-glucocorticoid complex (the bound fraction) and the remainder which is either unbound or loosely attached to albumin (the free fraction). We suggest that the biological importance of free vs. bound hormone depends on the location of interest (plasma or tissues), and the time frame of interest (current or future need). While a large body of evidence suggests that free hormones are the biologically active fraction, evidence also suggests that the bound fraction is a biologically relevant reservoir of glucocorticoids. We review two salient topics from the avian stress literature; stress-induced decreases in CBG capacity and glucocorticoid influences in life history strategies. These topics are discussed with an emphasis on free vs. bound hormone concentration and how that compares to current vs. future glucocorticoid needs.
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Affiliation(s)
- Jessica L Malisch
- Organismal Biology and Ecology, University of Montana, Missoula, MT 59812, USA.
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194
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Gagliardi L, Ho JT, Torpy DJ. Corticosteroid-binding globulin: the clinical significance of altered levels and heritable mutations. Mol Cell Endocrinol 2010; 316:24-34. [PMID: 19643166 DOI: 10.1016/j.mce.2009.07.015] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 07/15/2009] [Accepted: 07/15/2009] [Indexed: 02/05/2023]
Abstract
Corticosteroid-binding globulin (CBG) is the specific high-affinity plasma transport glycoprotein for cortisol. Stress-induced falls in CBG levels may heighten hypothalamic-pituitary-adrenal axis responses and CBG:tissue interactions may allow targeted cortisol delivery. Three genetic variants of CBG have been identified that reduce cortisol binding affinity and/or CBG levels. These include the Leuven and Lyon mutations which reduce CBG:cortisol binding affinity 3- and 4-fold, respectively, and the null mutation resulting in a 50% (heterozygote) or 100% (homozygote) reduction in CBG levels. The three reported null homozygotes demonstrate that complete CBG deficiency is not lethal, although it may be associated with hypotension and fatigue. The phenotype of a CBG null murine model included fatigue and immune defects. One community-based study revealed that severe CBG mutations are rare in idiopathic fatigue disorders. The mechanisms by which CBG mutations may cause fatigue are unknown. There are preliminary data of altered CBG levels in hypertension and in the metabolic syndrome; however, the nature of these associations is uncertain. Further studies may clarify the functions of CBG, and clinical observations may validate and/or extend the phenotypic features of various CBG mutations.
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Affiliation(s)
- Lucia Gagliardi
- School of Medicine, University of Adelaide, Adelaide, SA 5005, Australia
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195
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Rosner W, Hryb DJ, Kahn SM, Nakhla AM, Romas NA. Interactions of sex hormone-binding globulin with target cells. Mol Cell Endocrinol 2010; 316:79-85. [PMID: 19698759 DOI: 10.1016/j.mce.2009.08.009] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 07/28/2009] [Accepted: 08/11/2009] [Indexed: 10/20/2022]
Abstract
Sex hormone-binding globulin (SHBG) was initially described as a plasma protein synthesized in, and secreted by, the liver. It was discovered by its ability to bind certain androgens and estrogens and, for many years, was believed to serve as a transporter/reservoir for the steroids which it bound. Subsequently, it became clear that the cell membranes of selected tissues contained a receptor for SHBG (R(SHBG)). This review deals with what is known of that receptor - its anatomy, physiology and biochemistry.
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Affiliation(s)
- William Rosner
- Department of Medicine, St. Luke's/Roosevelt Hospital Center, College of, Physicians and Surgeons, Columbia University, New York, NY 10019, USA.
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196
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Fortunati N, Catalano MG, Boccuzzi G, Frairia R. Sex Hormone-Binding Globulin (SHBG), estradiol and breast cancer. Mol Cell Endocrinol 2010; 316:86-92. [PMID: 19770023 DOI: 10.1016/j.mce.2009.09.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 09/14/2009] [Accepted: 09/14/2009] [Indexed: 01/13/2023]
Abstract
The human serum Sex Hormone-Binding Globulin (SHBG) plays an important role in breast cancer pathophysiology and risk definition, since it regulates the bioavailable fraction of circulating estradiol. We here summarize data reported over the years concerning the involvement of SHBG and SHBG polymorphisms in the definition of breast cancer risk. We also report what is known about the direct action of SHBG in breast cancer cells, illustrating its interaction with these cells and the subsequent initiation of a specific intracellular pathway leading to cross-talk with the estradiol-activated pathway and, finally, to the inhibition of several effects of estradiol in breast cancer cells. In conclusion, as a result of its unique property of regulating the estrogen free fraction and cross-talking with the estradiol pathways, by inhibiting estradiol-induced breast cancer cell growth and proliferation, SHBG is associated with a reduced risk of developing the neoplasm after estrogen exposure.
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Affiliation(s)
- N Fortunati
- Laboratory of Oncological Endocrinology, AUO San Giovanni Battista, Turin, Italy.
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197
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LeBlanc ES, Wang PY, Janowsky JS, Neiss MB, Fink HA, Yaffe K, Marshall LM, Lapidus JA, Stefanick ML, Orwoll ES. Association between sex steroids and cognition in elderly men. Clin Endocrinol (Oxf) 2010; 72:393-403. [PMID: 19744108 PMCID: PMC2852485 DOI: 10.1111/j.1365-2265.2009.03692.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To examine the association of cognitive function with sex steroid and sex hormone binding globulin (SHBG) levels among elderly men. DESIGN Prospective cohort study, The Osteoporotic Fractures in Men Study (MrOS), consisting of 5995 US community dwelling men of 65 years or older. PATIENTS One thousand six hundred and two men were chosen randomly from MrOS cohort for sex steroid level measurements by Mass Spectrometry (MS) at baseline. Two thousand six hundred and twenty-three MrOS participants with sex steroids measured using RIA were also examined. MEASUREMENTS Baseline and follow-up (4.5 years later) performance on two cognitive tests: Trails B (executive function and motor speed) and 3MS (global cognitive function). Baseline total testosterone and oestradiol were measured by MS. Free testosterone (free-T) and free oestradiol (free-E) were calculated. SHBG was measured by radioimmunoassay. Data were analysed using linear regression. RESULTS Baseline free-T and free-E levels were not associated with cognitive performance or change in cognition, following adjustment for age, education, race, health status and alcohol use. Baseline SHBG levels were inversely associated with follow-up trails B (P = 0.03) and 3MS performance (P = 0.02). Higher SHBG was associated with an increased risk of cognitive decline. Total sex steroid levels were not associated with cognitive performance. CONCLUSIONS Despite large numbers of participants and rigorous sex steroid measurements, we did not observe an association between cognition and either testosterone or oestradiol levels. We conclude that endogenous sex steroids in the normal range are not related to executive function or global cognitive function in elderly men. High SHBG deserves further examination as a risk factor for cognitive decline.
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Affiliation(s)
- Erin S LeBlanc
- Division of Endocrinology, Oregon Health & Science University, Portland, OR 97239, USA.
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198
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Prange-Kiel J, Fester L, Zhou L, Jarry H, Rune GM. Estrus cyclicity of spinogenesis: underlying mechanisms. J Neural Transm (Vienna) 2010; 116:1417-25. [PMID: 19730783 PMCID: PMC3085745 DOI: 10.1007/s00702-009-0294-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 08/06/2009] [Indexed: 11/09/2022]
Abstract
Hippocampal spine density varies with the estrus cycle. The cyclic change in estradiol levels in serum was hypothesized to underlie this phenomenon, since treatment of ovariectomized animals with estradiol induced an increase in spine density in hippocampal dendrites of rats, as compared to ovariectomized controls. In contrast, application of estradiol to hippocampal slice cultures did not promote spinogenesis. In addressing this discrepancy, we found that hippocampal neurons themselves are capable of synthesizing estradiol de novo. Estradiol synthesis can be suppressed by aromatase inhibitors and by knock-down of Steroid Acute Regulatory Protein (StAR) and enhanced by substrates of steroidogenesis. Expression of estrogen receptors (ERs) and synaptic proteins, synaptogenesis, and long-term potentiation (LTP) correlated positively with aromatase activity in hippocampal cultures without any difference between genders. All effects due to inhibition of aromatase activity were rescued by application of estradiol to the cultures. Most importantly, gonadotropin-releasing hormone (GnRH) increased estradiol synthesis dose-dependently via an aromatase-mediated mechanism and consistently increased spine synapse density and spinophilin expression. As a consequence, our data suggest that cyclic fluctuations in spine synapse density result from pulsative release of GnRH from the hypothalamus and its effect on hippocampal estradiol synthesis, rather than from varying levels of serum estradiol. This hypothesis is further supported by higher GnRH receptor (GnRH-R) density in the hippocampus than in the cortex and hypothalamus and the specificity of estrus cyclicity of spinogenesis in the hippocampus, as compared to the cortex.
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Affiliation(s)
- Janine Prange-Kiel
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA
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199
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Perry JR, Weedon MN, Langenberg C, Jackson AU, Lyssenko V, Sparsø T, Thorleifsson G, Grallert H, Ferrucci L, Maggio M, Paolisso G, Walker M, Palmer CN, Payne F, Young E, Herder C, Narisu N, Morken MA, Bonnycastle LL, Owen KR, Shields B, Knight B, Bennett A, Groves CJ, Ruokonen A, Jarvelin MR, Pearson E, Pascoe L, Ferrannini E, Bornstein SR, Stringham HM, Scott LJ, Kuusisto J, Nilsson P, Neptin M, Gjesing AP, Pisinger C, Lauritzen T, Sandbaek A, Sampson M, Zeggini MAGICE, Lindgren CM, Steinthorsdottir V, Thorsteinsdottir U, Hansen T, Schwarz P, Illig T, Laakso M, Stefansson K, Morris AD, Groop L, Pedersen O, Boehnke M, Barroso I, Wareham NJ, Hattersley AT, McCarthy MI, Frayling TM. Genetic evidence that raised sex hormone binding globulin (SHBG) levels reduce the risk of type 2 diabetes. Hum Mol Genet 2010; 19:535-44. [PMID: 19933169 PMCID: PMC2798726 DOI: 10.1093/hmg/ddp522] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 11/16/2009] [Indexed: 01/05/2023] Open
Abstract
Epidemiological studies consistently show that circulating sex hormone binding globulin (SHBG) levels are lower in type 2 diabetes patients than non-diabetic individuals, but the causal nature of this association is controversial. Genetic studies can help dissect causal directions of epidemiological associations because genotypes are much less likely to be confounded, biased or influenced by disease processes. Using this Mendelian randomization principle, we selected a common single nucleotide polymorphism (SNP) near the SHBG gene, rs1799941, that is strongly associated with SHBG levels. We used data from this SNP, or closely correlated SNPs, in 27 657 type 2 diabetes patients and 58 481 controls from 15 studies. We then used data from additional studies to estimate the difference in SHBG levels between type 2 diabetes patients and controls. The SHBG SNP rs1799941 was associated with type 2 diabetes [odds ratio (OR) 0.94, 95% CI: 0.91, 0.97; P = 2 x 10(-5)], with the SHBG raising allele associated with reduced risk of type 2 diabetes. This effect was very similar to that expected (OR 0.92, 95% CI: 0.88, 0.96), given the SHBG-SNP versus SHBG levels association (SHBG levels are 0.2 standard deviations higher per copy of the A allele) and the SHBG levels versus type 2 diabetes association (SHBG levels are 0.23 standard deviations lower in type 2 diabetic patients compared to controls). Results were very similar in men and women. There was no evidence that this variant is associated with diabetes-related intermediate traits, including several measures of insulin secretion and resistance. Our results, together with those from another recent genetic study, strengthen evidence that SHBG and sex hormones are involved in the aetiology of type 2 diabetes.
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Affiliation(s)
- John R.B. Perry
- Genetics of Complex Traits, Peninsula College of Medicine and Dentistry, University of Exeter, Magdalen Road, Exeter EX1 2LU, UK
| | - Michael N. Weedon
- Genetics of Complex Traits, Peninsula College of Medicine and Dentistry, University of Exeter, Magdalen Road, Exeter EX1 2LU, UK
| | - Claudia Langenberg
- MRC Epidemiology Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Anne U. Jackson
- Department of Biostatistics, Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA
| | - Valeriya Lyssenko
- Department of Clinical Sciences, Diabetes and Endocrinology, Lund University, University Hospital Malmo, Malmo, Sweden
| | | | | | - Harald Grallert
- Institute of Epidemiology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Luigi Ferrucci
- Longitudinal Studies Section, Clinical Research Branch, National Institute on Aging, NIH, Baltimore, MD, USA
| | - Marcello Maggio
- Department of Internal Medicine and Medical Sciences, Section of Geriatrics, University of Parma, Parma, Italy
| | - Giuseppe Paolisso
- Department of Geriatrics and Metabolic Diseases Second, University of Naples, Naples, Italy
| | - Mark Walker
- Diabetes Research Group, School of Clinical Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Colin N.A. Palmer
- Biomedical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Felicity Payne
- Metabolic Disease Group, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Elizabeth Young
- MRC Epidemiology Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Christian Herder
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Narisu Narisu
- Genome Technology Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Mario A. Morken
- Genome Technology Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Lori L. Bonnycastle
- Genome Technology Branch, National Human Genome Research Institute, Bethesda, MD 20892, USA
| | - Katharine R. Owen
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital Old Road, Headington Oxford OX3 7LJ, UK
| | - Beverley Shields
- Genetics of Complex Traits, Peninsula College of Medicine and Dentistry, University of Exeter, Magdalen Road, Exeter EX1 2LU, UK
| | - Beatrice Knight
- Genetics of Complex Traits, Peninsula College of Medicine and Dentistry, University of Exeter, Magdalen Road, Exeter EX1 2LU, UK
| | - Amanda Bennett
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital Old Road, Headington Oxford OX3 7LJ, UK
| | - Christopher J. Groves
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital Old Road, Headington Oxford OX3 7LJ, UK
| | | | - Marjo Riitta Jarvelin
- Institute of Health Sciences and Biocenter Oulu, University of Oulu, Box 5000, Fin90014, Finland
| | - Ewan Pearson
- Biomedical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Laura Pascoe
- Diabetes Research Group, School of Clinical Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Ele Ferrannini
- Department of Internal Medicine, University of Pisa, School of Medicine, Pisa, Italy
| | - Stefan R. Bornstein
- Department of Medicine III, Division Prevention and Care of Diabetes, University of Dresden, 01307 Dresden, Germany
| | - Heather M. Stringham
- Department of Biostatistics, Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA
| | - Laura J. Scott
- Department of Biostatistics, Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA
| | - Johanna Kuusisto
- Department of Medicine, University of Kuopio and Kuopio University Hospital, Kuopio 70210, Finland
| | - Peter Nilsson
- Department of Clinical Sciences, Diabetes and Endocrinology, Lund University, University Hospital Malmo, Malmo, Sweden
| | - Malin Neptin
- Department of Clinical Sciences, Diabetes and Endocrinology, Lund University, University Hospital Malmo, Malmo, Sweden
| | | | - Charlotta Pisinger
- Research Centre for Prevention and Health, Glostrup University Hospital, Glostrup, Denmark
| | | | | | - Mike Sampson
- Department of Endocrinology and Diabetes, Norfolk and Norwich University Hospital NHS Trust, Norwich NR1 7UY, UK
| | | | - Cecilia M. Lindgren
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital Old Road, Headington Oxford OX3 7LJ, UK
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | | | | | - Torben Hansen
- Hagedorn Research Institute, 2820 Gentofte, Denmark
- Faculty of Health Science, University of Southern Denmark, Odense, Denmark and
| | - Peter Schwarz
- Department of Medicine III, Division Prevention and Care of Diabetes, University of Dresden, 01307 Dresden, Germany
| | - Thomas Illig
- Institute of Epidemiology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Markku Laakso
- Department of Medicine, University of Kuopio and Kuopio University Hospital, Kuopio 70210, Finland
| | | | - Andrew D. Morris
- Biomedical Research Institute, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Leif Groop
- Department of Clinical Sciences, Diabetes and Endocrinology, Lund University, University Hospital Malmo, Malmo, Sweden
| | - Oluf Pedersen
- Hagedorn Research Institute, 2820 Gentofte, Denmark
- Institute of Biomedical Science, University of Copenhagen, Copenhagen, Denmark
- Faculty of Health, University of Aarhus, Aarhus, Denmark
| | - Michael Boehnke
- Department of Biostatistics, Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA
| | - Inês Barroso
- Metabolic Disease Group, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Nicholas J. Wareham
- MRC Epidemiology Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Andrew T. Hattersley
- Genetics of Complex Traits, Peninsula College of Medicine and Dentistry, University of Exeter, Magdalen Road, Exeter EX1 2LU, UK
| | - Mark I. McCarthy
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital Old Road, Headington Oxford OX3 7LJ, UK
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Timothy M. Frayling
- Genetics of Complex Traits, Peninsula College of Medicine and Dentistry, University of Exeter, Magdalen Road, Exeter EX1 2LU, UK
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200
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Lakshman KM, Bhasin S, Araujo AB. Sex hormone-binding globulin as an independent predictor of incident type 2 diabetes mellitus in men. J Gerontol A Biol Sci Med Sci 2010; 65:503-9. [PMID: 20106959 DOI: 10.1093/gerona/glq002] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Low levels of sex hormone-binding globulin (SHBG) and total testosterone (T) in men have been associated with increased risk of type 2 diabetes mellitus (T2DM). As total T and SHBG levels are highly correlated, we determined whether SHBG influences the risk of T2DM through T or whether SHBG is an independent predictor of T2DM. METHODS Longitudinal analyses were conducted on men participating in the Massachusetts Male Aging Study, a population-based study of men aged 40-70 years. Of 1,709 men enrolled in 1987-1989, 1,156 were evaluated 7-10 years later and 853 after 15-17 years. Analyses were restricted to 1,128 men without T2DM at baseline. RESULTS Ninety new cases of T2DM were identified. After adjustment for age, body mass index, hypertension, smoking, alcohol intake, and physical activity, the hazard ratio (HR) for incident T2DM was 2.0 for each 1 SD decrease in SHBG (95% confidence interval [CI], 1.42-2.82, p < .001) and 1.29 for each 1 SD decrease in total T (95% CI, 1.01-1.66, p = .04). Free T was not associated with T2DM (HR = 1.03, 95% CI, 0.81-1.31, p = .79). The strong association of T2DM risk with SHBG persisted even after additional adjustment for free T (HR = 2.04, 95% CI, 1.44-2.87, p < .0001) or total T (HR = 1.95, 95% CI, 1.34-2.82, p = .0004). CONCLUSIONS SHBG is an independent predictor of incident T2DM even after adjusting for free T or total T. Free T is not significantly associated with T2DM. SHBG may contribute to the risk of T2DM through nonandrogenic mechanisms, which should be investigated as they may provide novel targets for diabetes prevention.
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Affiliation(s)
- Kishore M Lakshman
- Director of Epidemiology, New England Research Institutes, Inc., Watertown, MA 02472, USA
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