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Simien JM, Orellana GE, Phan HTN, Hu Y, Kurth EA, Ruf C, Kricek F, Wang Q, Smrcka AV, Haglund E. A Small Contribution to a Large System: The Leptin Receptor Complex. J Phys Chem B 2023; 127:2457-2465. [PMID: 36912891 DOI: 10.1021/acs.jpcb.3c01090] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Obesity is a classified epidemic, increasing the risk of secondary diseases such as diabetes, inflammation, cardiovascular disease, and cancer. The pleiotropic hormone leptin is the proposed link for the gut-brain axis controlling nutritional status and energy expenditure. Research into leptin signaling provides great promise toward discovering therapeutics for obesity and its related diseases targeting leptin and its cognate leptin receptor (LEP-R). The molecular basis underlying the human leptin receptor complex assembly remains obscure, due to the lack of structural information regarding the biologically active complex. In this work, we investigate the proposed receptor binding sites in human leptin utilizing designed antagonist proteins combined with AlphaFold predictions. Our results show that binding site I has a more intricate role in the active signaling complex than previously described. We hypothesize that the hydrophobic patch in this region engages a third receptor forming a higher-order complex, or a new LEP-R binding site inducing allosteric rearrangement.
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Affiliation(s)
- Jennifer M Simien
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Grace E Orellana
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Hoa T N Phan
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Yao Hu
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Emily A Kurth
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
| | - Christine Ruf
- NBS-C BioScience & Consulting GmbH, Vienna, 1230, Austria
| | - Franz Kricek
- NBS-C BioScience & Consulting GmbH, Vienna, 1230, Austria
| | - Qian Wang
- Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Alan V Smrcka
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan 48109, United States
| | - Ellinor Haglund
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
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Unique Genetic and Histological Signatures of Mouse Pericardial Adipose Tissue. Nutrients 2020; 12:nu12061855. [PMID: 32580292 PMCID: PMC7353424 DOI: 10.3390/nu12061855] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/15/2020] [Accepted: 06/19/2020] [Indexed: 12/21/2022] Open
Abstract
Obesity is a major risk factor for a plethora of metabolic disturbances including diabetes and cardiovascular disease. Accumulating evidence is showing that there is an adipose tissue depot-dependent relationship with obesity-induced metabolic dysfunction. While some adipose depots, such as subcutaneous fat, are generally metabolically innocuous, others such as visceral fat, are directly deleterious. A lesser known visceral adipose depot is the pericardial adipose tissue depot. We therefore set out to examine its transcriptional and morphological signature under chow and high-fat fed conditions, in comparison with other adipose depots, using a mouse model. Our results revealed that under chow conditions pericardial adipose tissue has uncoupling-protein 1 gene expression levels which are significantly higher than classical subcutaneous and visceral adipose depots. We also observed that under high-fat diet conditions, the pericardial adipose depot exhibits greatly upregulated transcript levels of inflammatory cytokines. Our results collectively indicate, for the first time, that the pericardial adipose tissue possesses a unique transcriptional and histological signature which has features of both a beige (brown fat-like) but also pro-inflammatory depot, such as visceral fat. This unique profile may be involved in metabolic dysfunction associated with obesity.
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Liu L, He D, Wang Y, Sheng M. Integrated analysis of DNA methylation and transcriptome profiling of polycystic ovary syndrome. Mol Med Rep 2020; 21:2138-2150. [PMID: 32323770 PMCID: PMC7115196 DOI: 10.3892/mmr.2020.11005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 07/30/2019] [Indexed: 12/16/2022] Open
Abstract
The present study aimed to identify potentially important biomarkers associated with polycystic ovary syndrome (PCOS) by integrating DNA methylation with transcriptome profiling. The transcription (E‑MTAB‑3768) and methylation (E‑MTAB‑3777) datasets were retrieved from ArrayExpress. Paired transcription and methylation profiling data of 10 cases of PCOS and 10 healthy controls were available for screening differentially expressed genes (DEGs) and differentially methylated genes (DMGs). Genes with a negative correlation between expression levels and methylation levels were retained by correlation analysis to construct a protein‑protein interaction (PPI) network. Subsequently, functional and pathway enrichment analyses were performed to identify genes in the PPI network. Additionally, a disease‑associated pathway network was also established. A total of 491 overlapping genes, and the expression levels of 237 genes, were negatively correlated with their methylation levels. Functional enrichment analysis revealed that genes in the PPI network were mainly involved with biological processes of cellular response to stress, negative regulation of the biosynthetic process, and regulation of cell proliferation. The constructed pathway network associated with PCOS led to the identification of four important genes (SPP1, F2R, IL12B and RBP4) and two important pathways (Jak‑STAT signaling pathway and neuroactive ligand‑receptor interaction). Taken, together, the results from the present study have revealed numerous important genes with abnormal DNA methylation levels and altered mRNA expression levels, along with their associated functions and pathways. These findings may contribute to an improved understanding of the possible pathophysiology of PCOS.
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Affiliation(s)
- Li Liu
- Reproductive Medical Center, Department of Gynecology and Obstetrics, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
| | - Dongyun He
- Reproductive Medical Center, Department of Gynecology and Obstetrics, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
| | - Yang Wang
- Department of Dermatology, The Affiliated Hospital of Changchun University of Chinese Medicine, Changchun, Jilin 130031, P.R. China
| | - Minjia Sheng
- Reproductive Medical Center, Department of Gynecology and Obstetrics, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130031, P.R. China
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Kim SO, Aberdeen G, Lynch TJ, Albrecht ED, Pepe GJ. Adipose and Liver Function in Primate Offspring with Insulin Resistance Induced by Estrogen Deprivation in Utero. ENDOCRINOLOGY, DIABETES AND METABOLISM JOURNAL 2017; 1:http://researchopenworld.com/wp-content/uploads/2017/10/EDMJ-2017-109-Gerald-J.-Pepe-USA.pdf. [PMID: 29983904 PMCID: PMC6035008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
PURPOSE We recently demonstrated that offspring delivered to baboons deprived of estrogen during the second half of gestation exhibited insulin resistance. Therefore, because skeletal muscle accounts for >80% of insulin dependent glucose disposal, we suggested that estrogen in utero programs factors in fetal skeletal muscle important for insulin sensitivity in offspring. However, liver and adipose are also sites of insulin action and adipose insulin resistance can increase serum free fatty acid (FFA) levels and thereby reduce skeletal muscle insulin sensitivity. Therefore, in the current study we determined whether estrogen-deprived offspring exhibit normal adipose and hepatic function. RESULTS The fasting serum levels of adiponectin, leptin, glucose, and analytes of liver function as well as the basal levels of serum FFA were similar in offspring of estrogen replete/suppressed baboons. Moreover, the normal glucose-induced decline in serum FFA levels measured in untreated offspring was also measured in offspring of letrozole-treated baboons. Fetal serum levels of adiponectin and leptin in late gestation also were similar and expression of nitrotyrosine negligible in fetal liver and adipose of untreated and letrozole-treated animals. CONCLUSIONS These results indicate that offspring of letrozole-treated baboons have normal adipose and liver function and do not exhibit adipose insulin resistance. Therefore, we suggest that the insulin resistance observed in estrogen-deprived offspring primarily reflects a decline in insulin-stimulated glucose clearance by skeletal muscle and which supports our original suggestion that estrogen in utero programs factors in fetal skeletal muscle that promote insulin sensitivity in offspring.
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Affiliation(s)
- Soon Ok Kim
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Graham Aberdeen
- Departments of Obstetrics/Gynecology/Reproductive Sciences and Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Terrie J. Lynch
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA
| | - Eugene D. Albrecht
- Departments of Obstetrics/Gynecology/Reproductive Sciences and Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Gerald J. Pepe
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA, USA
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Smith SI. PPAR-γ receptor agonists-a review of their role in diabetic management in Trinidad and Tobago. Mol Cell Biochem 2016; 263:189-210. [PMID: 27520678 DOI: 10.1023/b:mcbi.0000041861.79585.4b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The PPAR-γ receptor agonists, as a relatively new and perhaps still not very widely used class of antidiabetic agent in the Caribbean and particularly the Trinidadian context, possess pharmacologic properties that certainly have been shown to have impact on many of the inflammatory, metabolic, biochemical and structural macrovascular aberrations that occur in the type 2 diabetic. Activation of PPAR(gamma) nuclear receptors regulates the transcription of insulin-responsive genes involved in the control of glucose production, transport, and utilization. PPAR(gamma)-responsive genes also participate in the regulation of fatty acid metabolism, an important contributory pathogenic factor in this subset of patients. The unique mode of action of this class of therapeutic agent addresses a range of anomalies occurring at the cellular and sub-cellular level that are injurious to the diabetic. My aim in addressing the issue of the potential impact of PPAR-γ receptor agonists on cardiovascular disease (CVD) morbidity and mortality in the diabetic, is first, to seek to enhance both an awareness of, and greater familiarity among our own physicians, with this class of drug, and secondly, to effect a timely review of the recent literature as it relates to the tremendous possibilities for the potential clinical gains that might accrue from their use, in so far as this may serve to ameliorate the ravages of the CVD disease that all too tragically attends the type 2 diabetic, and more specifically those with the insulin resistance syndrome. (Mol Cell Biochem 263: 189-210, 2004).
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Sunflower Oil but Not Fish Oil Resembles Positive Effects of Virgin Olive Oil on Aged Pancreas after Life-Long Coenzyme Q Addition. Int J Mol Sci 2015; 16:23425-45. [PMID: 26426013 PMCID: PMC4632707 DOI: 10.3390/ijms161023425] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/21/2015] [Accepted: 09/22/2015] [Indexed: 12/15/2022] Open
Abstract
An adequate pancreatic structure is necessary for optimal organ function. Structural changes are critical in the development of age-related pancreatic disorders. In this context, it has been reported that different pancreatic compartments from rats were affected according to the fat composition consumed. Since there is a close relationship between mitochondria, oxidative stress and aging, an experimental approach has been developed to gain more insight into this process in the pancreas. A low dosage of coenzyme Q was administered life-long in rats in order to try to prevent pancreatic aging-related alterations associated to some dietary fat sources. According to that, three groups of rats were fed normocaloric diets containing Coenzyme Q (CoQ) for two years, where virgin olive, sunflower, or fish oil was included as unique fat source. Pancreatic samples for microscopy and blood samples were collected at the moment of euthanasia. The main finding is that CoQ supplementation gives different results according to fat used in diet. When sunflower oil was the main fat in the diet, CoQ supplementation seems to improve endocrine pancreas structure and in particular β-cell mass resembling positive effects of virgin olive oil. Conversely, CoQ intake does not seem to improve the structural alterations of exocrine compartment previously observed in fish oil fed rats. Therefore CoQ may improve pancreatic alterations associated to the chronic intake of some dietary fat sources.
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Chen XX, Yang T. Roles of leptin in bone metabolism and bone diseases. J Bone Miner Metab 2015; 33:474-85. [PMID: 25777984 DOI: 10.1007/s00774-014-0569-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 01/16/2014] [Indexed: 02/05/2023]
Abstract
Adipose tissue has been more accepted as an active contributor to whole body homeostasis, rather than just a fat depot, since leptin, a 16 kDa protein, was discovered as the product of the obese gene in 1994. With more and more studies conducted on this hormone, it has been shown that there is a close relationship between adipose tissue and bone, which have important effects on each other. Bone is the source of many hormones, such as osteocalcin, that can affect energy metabolism and then the anabolism or catabolism of fat tissue. In contrast, the adipose tissue synthesizes and releases a series of adipokines, which are involved in bone metabolism through direct or indirect effects on bone formation and resorption. Interestingly, leptin, one of the most important cytokines derived from fat tissue, seems to account for the largest part of effects on bone, through direct or indirect involvement in bone remodeling and by playing a significant role in many bone diseases, such as osteoporosis, osteoarthritis, rheumatic arthritis, bone tumors and even fractures. In this review, we will discuss the progress in leptin research, particularly focusing on the roles of leptin in bone diseases.
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Affiliation(s)
- Xu Xu Chen
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, 610041, Sichuan, People's Republic of China
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Ferrandino I, Monaco A, Grimaldi MC. Effects of leptin on FSH cells in the pituitary gland of Podarcis siculus. C R Biol 2015; 338:180-4. [DOI: 10.1016/j.crvi.2014.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/17/2014] [Accepted: 12/18/2014] [Indexed: 11/25/2022]
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Rosales Nieto CA, Thompson AN, Macleay CA, Briegel JR, Hedger MP, Ferguson MB, Martin GB. Relationships among body composition, circulating concentrations of leptin and follistatin, and the onset of puberty and fertility in young female sheep. Anim Reprod Sci 2014; 151:148-56. [PMID: 25458319 DOI: 10.1016/j.anireprosci.2014.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 10/01/2014] [Accepted: 10/05/2014] [Indexed: 12/22/2022]
Abstract
The onset of puberty depends on the attainment of critical body mass, so should also be affected by increases in the rate of accumulation of muscle and adipose tissue. Adipose tissue and reproduction are linked by leptin. For muscle, a link has not yet been identified, although one possibility is follistatin. We assessed the relationships among circulating concentrations of follistatin and leptin and the rates of growth and accumulation of muscle and fat during pubertal development in female sheep. We used 326 animals with known phenotypic values for live weight (LW), depths of eye muscle (EMD) and fat (FAT), and known breeding values at post-weaning age for body mass (PWT) and depths of eye muscle (PEMD) and fat (PFAT). Leptin concentration was positively correlated with values for EMD, PEMD, FAT, PFAT, LW and PWT (P<0.001), whereas follistatin concentration was negatively correlated with values for EMD and PWT (P<0.001), and PEMD (P<0.01) and FAT (P<0.05). Leptin concentration was negatively related to age and positively related to live weight at first oestrus and the proportion of females that attained puberty (P≤0.05), and to fertility and reproductive rate (P<0.01). Follistatin concentration was negatively related to live weight at first oestrus and to fertility (P<0.01) and reproductive rate (P<0.05). There were positive correlations (P<0.001) between muscle accumulation and leptin concentration, and between muscle accumulation and reproductive performance. We conclude that leptin and follistatin are probably both involved in effects of accelerated accumulation of muscle and adipose tissues on the onset of puberty.
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Affiliation(s)
- C A Rosales Nieto
- CRC for Sheep Industry Innovation and the University of New England, Armidale, NSW 2351, Australia; Department of Agriculture and Food of Western Australia, South Perth, WA 6151, Australia; The UWA Institute of Agriculture and School of Animal Biology, University of Western Australia, Crawley, WA 6009, Australia
| | - A N Thompson
- CRC for Sheep Industry Innovation and the University of New England, Armidale, NSW 2351, Australia; Department of Agriculture and Food of Western Australia, South Perth, WA 6151, Australia; School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - C A Macleay
- Department of Agriculture and Food of Western Australia, South Perth, WA 6151, Australia
| | - J R Briegel
- Department of Agriculture and Food of Western Australia, South Perth, WA 6151, Australia
| | - M P Hedger
- Monash Institute of Medical Research, Monash University, Victoria 3168, Australia
| | - M B Ferguson
- CRC for Sheep Industry Innovation and the University of New England, Armidale, NSW 2351, Australia; Department of Agriculture and Food of Western Australia, South Perth, WA 6151, Australia; School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - G B Martin
- The UWA Institute of Agriculture and School of Animal Biology, University of Western Australia, Crawley, WA 6009, Australia; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Oxford OX3 9DU, UK.
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Park S, Fujishita C, Komatsu T, Kim SE, Chiba T, Mori R, Shimokawa I. NPY antagonism reduces adiposity and attenuates age-related imbalance of adipose tissue metabolism. FASEB J 2014; 28:5337-48. [PMID: 25205743 DOI: 10.1096/fj.14-258384] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
An orexigenic hormone, neuropeptide Y (NPY), plays a role not only in the hypothalamic regulation of appetite, but also in the peripheral regulation of lipid metabolism. However, the intracellular mechanisms triggered by NPY to regulate lipid metabolism are poorly understood. Here we report that NPY deficiency reduces white adipose tissue (WAT) mass and ameliorates the age-related imbalance of adipose tissue metabolism in mice. Gene expression involved in adipogenesis/lipogenesis was found to decrease, whereas proteins involved in lipolysis increased in gonadal WAT (gWAT) of NPY-knockout mice. These changes were associated with an activated SIRT1- and PPARγ-mediated pathway. Moreover, the age-related decrease of de novo lipogenesis in gWAT and thermogenesis in inguinal WAT was inhibited by NPY deficiency. Further analysis using 3T3-L1 cells showed that NPY inhibited lipolysis through the Y1 receptor and enhanced lipogenesis following a reduction in cAMP response element-binding protein (CREB) and SIRT1 protein expression. Therefore, NPY appears to act as a key regulator of adipose tissue metabolism via the CREB-SIRT1 signaling pathway. Taken together, NPY deficiency reduces adiposity and ameliorates the age-related imbalance of adipose tissue metabolism, suggesting that antagonism of NPY may be a promising target for drug development to prevent age-related metabolic diseases.
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Affiliation(s)
- Seongjoon Park
- Department of Pathology, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Nagasaki City, Japan
| | - Chika Fujishita
- Department of Pathology, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Nagasaki City, Japan
| | - Toshimitsu Komatsu
- Department of Pathology, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Nagasaki City, Japan
| | - Sang Eun Kim
- Department of Pathology, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Nagasaki City, Japan
| | - Takuya Chiba
- Department of Pathology, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Nagasaki City, Japan
| | - Ryoichi Mori
- Department of Pathology, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Nagasaki City, Japan
| | - Isao Shimokawa
- Department of Pathology, Graduate School of Biomedical Sciences, Nagasaki University School of Medicine, Nagasaki City, Japan
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Lin S, YuJun L, XiaoMing X, WenWen R. Expression and significance of leptin receptor, p-STAT3 and p-AKT in diffuse large B-cell lymphoma. Acta Histochem 2014; 116:126-30. [PMID: 24054064 DOI: 10.1016/j.acthis.2013.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 06/16/2013] [Accepted: 06/17/2013] [Indexed: 01/11/2023]
Abstract
We investigated the expression and clinical significance of leptin receptor (OBR), p-STAT3 and p-AKT in patients with diffuse large B-cell lymphoma (DLBCL) by immunohistochemical analysis. Immunohistochemistry revealed high expression of OBR, p-STAT3 and p-AKT in 45.0% (36/80), 28.8% (23/80) and 18.8% (15/80) cases of DLBCL, respectively, and minimal staining in 100% (20/20) cases of RLH (P<0.05). Compared with GCB group, the non-GCB group had higher p-STAT3 expression rate (21/57 vs. 2/23, P<0.01). The expression of OBR was positively related with that of p-STAT3 and p-AKT in DLBCL patients (P<0.05). Our data suggest that OBR stimulates the JAK/STAT and PI3K/AKT signaling pathway and induces the phosphorylation of STAT3 and AKT. This may be involved in carcinogenesis and prognosis of DLBCL. The specific inhibitions could interfere in the combination of leptin with OBR and obstruct the JAK/STAT and PI3K/AKT signaling pathways, which could lead to new research and treatment strategies for DLBCL treatment.
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Zhou L, Yuan C, Zhang J, Yu R, Huang M, Adcock IM, Yao X. Circulating leptin concentrations in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis. Respiration 2013; 86:512-22. [PMID: 24158120 DOI: 10.1159/000354191] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 07/02/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Weight loss is a clinically important risk factor indicating a poor prognosis in chronic obstructive pulmonary disease (COPD). Leptin is an important regulator of food intake and energy expenditure. OBJECTIVES To conduct a meta-analysis to determine whether the level of leptin is related to the disease status of COPD. METHODS Studies published before December 2012 were identified by searching PubMed, Embase and the Cochrane Database. Observational studies comparing circulating leptin levels between COPD patients and healthy controls were included. Data were independently extracted by two investigators and analyzed using Stata 12.0 software. RESULTS Ten articles were included in the meta-analysis. Circulating leptin levels were correlated with the body mass index (BMI) as well as percent fat mass in stable COPD patients. The correlation coefficient tended to be weaker during exacerbation. A positive correlation between leptin and tumor necrosis factor (TNF)-α levels was found in COPD exacerbations, while it disappeared in patients with stable disease. Most studies indicated that circulating leptin levels in stable COPD patients were not significantly different from those in healthy controls when adjusted for gender and BMI, whilst leptin levels tended to elevate in exacerbation groups. CONCLUSIONS The normal regulatory mechanism of leptin is maintained in stable COPD patients despite weight loss. The additional correlation between leptin and TNF-α during exacerbations may support the closer association of leptin with changes in nutritional parameters and suggests its valuable role in the evaluation of systemic inflammatory responses in COPD patients during exacerbation, which merits further study.
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Affiliation(s)
- Lin Zhou
- Department of Respiratory Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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Gentry Jr. G, Gentry L, Godke R. The effect of exogenous follicle stimulating hormone (FSH) and endogenous plasma leptin concentrations on the pregnancy rate of beef heifers subjected to fixed-timed artificial insemination (FTAI). Anim Reprod Sci 2013; 138:49-54. [DOI: 10.1016/j.anireprosci.2013.01.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 01/12/2013] [Accepted: 01/27/2013] [Indexed: 11/28/2022]
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Tourkantonis I, Kiagia M, Peponi E, Tsagouli S, Syrigos KN. The Role of Leptin in Cancer Pathogenesis. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/jct.2013.42080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Matsui H, Yokoyama T, Tanaka C, Sunaga H, Koitabashi N, Takizawa T, Arai M, Kurabayashi M. Pressure mediated hypertrophy and mechanical stretch up-regulate expression of the long form of leptin receptor (ob-Rb) in rat cardiac myocytes. BMC Cell Biol 2012; 13:37. [PMID: 23270329 PMCID: PMC3543168 DOI: 10.1186/1471-2121-13-37] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 12/21/2012] [Indexed: 12/14/2022] Open
Abstract
Background Hyperleptinemia is known to participate in cardiac hypertrophy and hypertension, but the relationship between pressure overload and leptin is poorly understood. We therefore examined the expression of leptin (ob) and the leptin receptor (ob-R) in the pressure-overloaded rat heart. We also examined gene expressions in culture cardiac myocytes to clarify which hypertension-related stimulus induces these genes. Results Pressure overload was produced by ligation of the rat abdominal aorta, and ob and ob-R isoform mRNAs were measured using a real-time polymerase chain reaction (PCR). We also measured these gene expressions in neonatal rat cardiac myocytes treated with angiotensin II (ANGII), endothelin-1 (ET-1), or cyclic mechanical stretch. Leptin and the long form of the leptin receptor (ob-Rb) gene were significantly increased 4 weeks after banding, but expression of the short form of the leptin receptor (ob-Ra) was unchanged. ob-Rb protein expression was also detected by immunohistochemistry in hypertrophied cardiac myocytes after banding. Meanwhile, plasma leptin concentrations were not different between the control and banding groups. In cultured myocytes, ANGII and ET-1 increased only ob mRNA expression. However, mechanical stretch activated both ob and ob-Rb mRNA expression in a time-dependent manner, but ob-Ra mRNA was unchanged by any stress. Conclusions We first demonstrated that both pressure mediated hypertrophy and mechanical stretch up-regulate ob-Rb gene expression in heart and cardiac myocytes, which are thought to be important for leptin action in cardiac myocytes. These results suggest a new local mechanism by which leptin affects cardiac remodeling in pressure-overloaded hearts.
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Affiliation(s)
- Hiroki Matsui
- Department of Laboratory Sciences, Gunma University Graduate School of Health Sciences, Showa-machi, Maebashi, Japan
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Pagano C, Dorigo A, Nisoli E, Tonello C, Calcagno A, Tami V, Granzotto M, Carruba MO, Federspil G, Vettor R. Role of Insulin and Free Fatty Acids in the Regulation ofobGene Expression and Plasma Leptin in Normal Rats. ACTA ACUST UNITED AC 2012; 12:2062-9. [PMID: 15687408 DOI: 10.1038/oby.2004.257] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE It is under debate whether free fatty acids (FFAs) play an independent role in the regulation of adipose cell functions. In this study, we evaluated whether leptin secretion induced by FFA is due directly to an increased FFA availability or whether it is mediated by insulin levels. RESEARCH METHODS AND PROCEDURES To test this hypothesis, we compared the effects of six different experimental designs, with different FFA and insulin levels, on plasma leptin: euglycemic clamp, euglycemic clamp + FFA infusion, FFA infusion alone, FFA + somatostatin infusion, somatostatin infusion alone, and saline infusion. RESULTS Our results showed that euglycemic clamp, FFA infusion, or both in combination induced a similar increment of circulating leptin (3.31 +/- 0.30, 3.40 +/- 0.90, and 3.35 +/- 0.80 ng/mL, respectively). Moreover, the inhibition of FFA-induced insulin increase by means of somatostatin infusion completely abolished the rise of leptin in response to FFA (1.05 +/- 0.30 vs. 3.40 +/- 0.90 ng/mL, p < 0.001). DISCUSSION In conclusion, our data showed that the effects of high FFA levels on plasma leptin were mediated by the rise of insulin concentration. These data confirm a major role for insulin in the regulation of leptin secretion from rat adipose tissue and support the hypothesis that leptin secretion is coupled to net triglyceride synthesis in adipose tissue.
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Affiliation(s)
- Claudio Pagano
- Endocrine Metabolic Library, Department of Medical and Surgical Sciences, University of Padova, Padova, Italy.
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Metabolic manifestations of insulin deficiency do not occur without glucagon action. Proc Natl Acad Sci U S A 2012; 109:14972-6. [PMID: 22891336 DOI: 10.1073/pnas.1205983109] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
To determine unambiguously if suppression of glucagon action will eliminate manifestations of diabetes, we expressed glucagon receptors in livers of glucagon receptor-null (GcgR(-/-)) mice before and after β-cell destruction by high-dose streptozotocin. Wild type (WT) mice developed fatal diabetic ketoacidosis after streptozotocin, whereas GcgR(-/-) mice with similar β-cell destruction remained clinically normal without hyperglycemia, impaired glucose tolerance, or hepatic glycogen depletion. Restoration of receptor expression using adenovirus containing the GcgR cDNA restored hepatic GcgR, phospho-cAMP response element binding protein (P-CREB), and phosphoenol pyruvate carboxykinase, markers of glucagon action, rose dramatically and severe hyperglycemia appeared. When GcgR mRNA spontaneously disappeared 7 d later, P-CREB declined and hyperglycemia disappeared. In conclusion, the metabolic manifestations of diabetes cannot occur without glucagon action and, once present, disappear promptly when glucagon action is abolished. Glucagon suppression should be a major therapeutic goal in diabetes.
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In situ hybridization and immunohistochemical localization of leptin hormone and leptin receptor in the seminal vesicle and prostate gland of adult rat. Acta Histochem 2012; 114:185-91. [PMID: 21621828 DOI: 10.1016/j.acthis.2011.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 04/17/2011] [Accepted: 04/26/2011] [Indexed: 12/14/2022]
Abstract
The role of leptin in the regulation of male reproductive function is still a matter of debate. Knowledge about a possible source of leptin in the seminal plasma may therefore be helpful in identifying and elucidating the physiological role of leptin hormone in male reproduction. In our investigation, the expression of leptin and its long receptor isoform (Ob-Rb) was studied in adult male Wistar rats using RT-PCR, Southern blot, in situ hybridization and immunohistochemistry. RT-PCR analysis revealed the expression of both leptin and its Ob-Rb in the seminal vesicle and prostate gland. In situ hybridization also localized the mRNA transcripts of leptin and Ob-Rb in the glandular secretory epithelial cells of prostate gland and seminal vesicle. Immunohistochemistry detected the leptin hormone in the lining epithelium of both male genital glands. In conclusion, these findings suggest that the seminal vesicle and prostate gland could be the possible sources of leptin in the seminal plasma. This leptin might have a direct (paracrine, autocrine or both) effect on epithelial cells of the accessory male genital glands, on the spermatozoa via spermatozoan leptin receptors.
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González-Castejón M, Rodriguez-Casado A. Dietary phytochemicals and their potential effects on obesity: A review. Pharmacol Res 2011; 64:438-55. [DOI: 10.1016/j.phrs.2011.07.004] [Citation(s) in RCA: 207] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 07/11/2011] [Indexed: 12/20/2022]
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Abstract
Psoriasis is a chronic inflammatory and immune-mediated disease associated with several comorbidities, such as obesity, hypertension, diabetes mellitus, dyslipidemia and cardiovascular disorder. These comorbidities are components of metabolic syndrome. The pathogenesis of metabolic syndrome is supposed to be related to increased levels of adipocytokines, such as tumor necrosis factor-α (TNF-α) and adiponectin. Recent study has revealed a high prevalence of metabolic syndrome in psoriatics compared with other skin diseases. Biologic agents, including anti-TNF-α antibodies, are recommended as the first-line treatment for psoriatics with metabolic syndrome. This article reviews the association of psoriasis and metabolic syndrome in terms of adipocytokines and evaluates the role of biologic agents in the treatment of psoriasis.
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Kuehnen P, Laubner K, Raile K, Schöfl C, Jakob F, Pilz I, Päth G, Seufert J. Protein phosphatase 1 (PP-1)-dependent inhibition of insulin secretion by leptin in INS-1 pancreatic β-cells and human pancreatic islets. Endocrinology 2011; 152:1800-8. [PMID: 21427225 DOI: 10.1210/en.2010-1094] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Leptin inhibits insulin secretion from pancreatic β-cells, and in turn, insulin stimulates leptin biosynthesis and secretion from adipose tissue. Dysfunction of this adipoinsular feedback loop has been proposed to be involved in the development of hyperinsulinemia and type 2 diabetes mellitus. At the molecular level, leptin acts through various pathways, which in combination confer inhibitory effects on insulin biosynthesis and secretion. The aim of this study was to identify molecular mechanisms of leptin action on insulin secretion in pancreatic β-cells. To identify novel leptin-regulated genes, we performed subtraction PCR in INS-1 β-cells. Regulated expression of identified genes was confirmed by RT-PCR and Northern and Western blotting. Furthermore, functional impact on β-cell function was characterized by insulin-secretion assays, intracellular Ca²(+) concentration measurements, and enzyme activity assays. PP-1α, the catalytic subunit of protein phosphatase 1 (PP-1), was identified as a novel gene down-regulated by leptin in INS-1 pancreatic β-cells. Expression of PP-1α was verified in human pancreatic sections. PP-1α mRNA and protein expression is down-regulated by leptin, which culminates in reduction of PP-1 enzyme activity in β-cells. In addition, glucose-induced insulin secretion was inhibited by nuclear inhibitor of PP-1 and calyculin A, which was in part mediated by a reduction of PP-1-dependent calcium influx into INS-1 β-cells. These results identify a novel molecular pathway by which leptin confers inhibitory action on insulin secretion, and impaired PP-1 inhibition by leptin may be involved in dysfunction of the adipoinsular axis during the development of hyperinsulinemia and type 2 diabetes mellitus.
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Affiliation(s)
- Peter Kuehnen
- Institute of Experimental Pediatric Endocrinology, Charité Children's Hospital, Universitätsmedizin Berlin, Berlin, Germany.
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Khokhar KK, Sidhu S, Kaur G. Correlation between leptin level and hypertension in normal and obese pre- and postmenopausal women. Eur J Endocrinol 2010; 163:873-8. [PMID: 20841449 DOI: 10.1530/eje-10-0714] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE The present study was aimed at evaluating the correlation between leptin and hypertension in normal and obese hypertensive pre- (Pre-M) and postmenopausal (Post-M) women of Jalandhar city (Punjab, India). DESIGN For the present study, 78 Pre-M and Post-M women were recruited in four categories as follows: i) normal normotensive, ii) obese normotensive, iii) normal hypertensive, and iv) obese hypertensive. Body mass index was considered as the index of obesity. Guidelines given by JNC-VII were followed for the assessment of hypertension. Leptin was assayed by sandwich ELISA, and estradiol (E(2)) was assayed by competitive ELISA. RESULTS Leptin level was found to be significantly higher in normal Pre-M women (P<0.02) than that of normal Post-M women. Obese subjects had significantly higher leptin level (P<0.001) than the normal women. In the case of hypertensive subjects, leptin level was significantly higher than that of normotensive counterparts. E(2) level was found significantly lower in Post-M women (P<0.001) than that of Pre-M women as well as in hypertensive women than that of normotensive subjects. A positive correlation was observed between blood pressure (BP) and leptin, but significant association was observed in hypertensive normal and obese Pre-M and Post-M women only. CONCLUSION It is concluded from the present findings that leptin contributes to the regulation of BP in hypertensive normal as well as in the obese Pre-M and Post-M women. So, leptin may be a regulator of BP in hypertensive women independent of the degree of obesity and the menopausal status.
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Affiliation(s)
- Kawaljit Kaur Khokhar
- Department of Human Genetics, Guru Nanak Dev University, Amritsar 143005, Punjab, India
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Abstract
BACKGROUND AND OBJECTIVE We previously reported that baclofen, a GABA(B) agonist, reduces body weight in obese mice. In this clinical study, we examined the possibility that baclofen might serve as an effective therapeutic agent for obesity in humans. METHODS Seven women and three men ranging from 25-51 years of age and 31.3-41.0 kg/m(2) body mass index were included in the study. Baclofen, which was started at a dose of 15 mg/day and increased to 30 mg/day in 10 days, was administered for 12 weeks. RESULTS Administration of baclofen for 12 weeks significantly decreased both body weight (baseline: 93.30 ± 9.80 kg, 12 weeks: 91.70 ± 10.30 kg) and waist circumference (baseline: 107.9 ± 9.0 cm, 12 weeks: 105.6 ± 10.0 cm). Serum leptin levels, which possibly reflect the amount of adipose stores, were also decreased significantly by the treatment. On the other hand, there were no significant changes in the blood pressure or metabolism of glucose and lipid. No adverse effects were observed. CONCLUSION Although the anti-obesity effects of baclofen in the present study were mild, this pilot study suggests the possibility that baclofen might serve as a new anti-obesity drug in humans.
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Affiliation(s)
- Hiroshi Arima
- Department of Endocrinology and Diabetes, Field of Internal Medicine, Nagoya University Graduate School of Medicine.
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Rong X, Li Y, Ebihara K, Zhao M, Aini W, Kusakabe T, Hirata M, Miyamoto L, Murray M, Nakao K. An adipose tissue-independent insulin-sensitizing action of telmisartan: a study in lipodystrophic mice. J Pharmacol Exp Ther 2009; 331:1096-103. [PMID: 19770292 DOI: 10.1124/jpet.109.157099] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Adipose tissue plays an important role in energy balance and metabolism and is the major target for insulin-sensitizing peroxisome proliferator-activated receptor (PPAR) gamma agonists. The angiotensin II type 1 receptor blocker telmisartan, a partial agonist of PPAR-gamma, has been demonstrated to improve insulin sensitivity. However, there is uncertainty about the sites of its action. Here, we demonstrate that treatment with telmisartan (3 mg/kg p.o.) for 7 weeks decreased plasma glucose levels in oral glucose and insulin tolerance tests and the index of the homeostasis model assessment of insulin resistance in A-ZIP/F-1 transgenic mice, an animal model of lipodystrophy. These effects were accompanied by decreases in circulating triglyceride and fatty acid levels. However, this treatment did not affect body weight and plasma adiponectin, leptin, and corticosterone levels. In A-ZIP/F-1 mouse liver the transcripts encoding PPAR-gamma and its downstream lipogenic genes were highly up-regulated, consistent with increased hepatic triglyceride content and lipid droplet accumulation. Telmisartan reversed these effects and also down-regulated mRNAs encoding gluconeogenic genes. Thus, the present findings are consistent with a novel mode of insulin-sensitizing action of telmisartan, involving an adipose tissue-independent pathway. Telmisartan-elicited down-regulation of hepatic expression of PPAR-gamma-regulated lipogenic genes is associated with amelioration of fatty liver.
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Affiliation(s)
- X Rong
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
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Şengül ÖB, Mungan T, Erdemoğlu E, İslamoğlu G, Kıyak N. Investigation of the correlation between 100 gram oral glucose tolerance test results and maternal leptin levels during pregnancy. J Turk Ger Gynecol Assoc 2009; 10:158-161. [PMID: 24591860 PMCID: PMC3939120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 08/14/2009] [Indexed: 06/03/2023] Open
Abstract
OBJECTIVE To investigate the correlation between maternal leptin levels and 100 gram oral glucose test (OGTT) results as well as the correlation between leptin levels and the development of gestational diabetes mellitus (GDM) and glucose intolerance during pregnancy. MATERIAL AND METHOD 104 subjects with gestational weeks ranging from 24 to 32 weeks who had increased 50 gr OGTT values (>140) were included in this study. After the screening test, 100 gr OGTT was administered to the subjects. Sixty cases were selected from these subjects; twenty patients with one abnormal test result were identified as "glucose intolerant" group (Group 1), 20 patients with two abnormal test values were diagnosed with GDM (Group 2) and 20 patients with normal test results constituted the control group. The serum leptin levels of the groups were measured with enzyme linked immunosorbent assay (ELISA). RESULTS The serum leptin level was 8.4±5.1 ng/ml for group 1, 9.1±5.3 ng/ml for group 2 and 6.3±4.6 ng/ml for the control group. Although serum leptin levels for group 1 and 2 was observed to be higher than the control group, the result was not statistically significant (p>0.05). This result did not change after adjusting for body mass index (BMI). CONCLUSION There is no statistically significant difference between leptin levels among three groups.
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Affiliation(s)
- Özlem Baykara Şengül
- Department of Obstetrics and Gynecology, Zekai Tahir Burak Womens Health Hospital, Ankara, Turkey
| | - Tamer Mungan
- Department of Obstetrics and Gynecology, Faculty of Medicine, Süleyman Demirel University, Isparta, Turkey
| | - Evrim Erdemoğlu
- Department of Obstetrics and Gynecology, Faculty of Medicine, Süleyman Demirel University, Isparta, Turkey
| | - Göksel İslamoğlu
- Department of Obstetrics and Gynecology, Zekai Tahir Burak Womens Health Hospital, Ankara, Turkey
| | - Nuran Kıyak
- Department of Obstetrics and Gynecology, Zekai Tahir Burak Womens Health Hospital, Ankara, Turkey
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McCormick SD. Evolution of the hormonal control of animal performance: Insights from the seaward migration of salmon. Integr Comp Biol 2009; 49:408-22. [PMID: 21665830 DOI: 10.1093/icb/icp044] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The endocrine system is the key mediator of environmental and developmental (internal) information, and is likely to be involved in altering the performance of animals when selection has favored phenotypic plasticity. The endocrine control of performance should be especially pronounced in animals that undergo a developmental shift in niche, such as occurs in migratory species. By way of example, I review the developmental and environmental control of the preparatory changes for seawater entry of juvenile salmon (known as smolting) and its hormonal regulation. There is a size threshold for smolt development in juvenile Atlantic salmon that results in greater sensitivity of the growth hormone and cortisol axes to changes in daylength. These hormones, in turn, have broad effects on survival, ion homeostasis, growth and swimming performance during entry into seawater. Migratory niche shifts and metamorphic events are extreme examples of the role of hormones in animal performance and represent one end of a continuum. A framework for predicting when hormones will be involved in performance of animals is presented. Endocrine involvement in performance will be more substantial when (1) selection differentials on traits underlying performance are high and temporally discontinuous over an animal's lifetime, (2) the energetic and fitness costs of maintaining performance plasticity are less than those of constant performance, (3) cues for altering performance are reliable indicators of critical environmental conditions, require neurosensory input, and minimize effects of lag, and (4) the need for coordination of organs, tissues and cells to achieve increased performance is greater. By examining these impacts of selection, endocrinologists have an opportunity to contribute to the understanding of performance, phenotypic plasticity, and the evolution of life-history traits.
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-Samak MA, Khuzaie R, Abu-Hashee M, Jaradeh M, Fawzi M. Relationship of Vitamin B12 Deficiency with Overweight in Male Jordanian Youth. ACTA ACUST UNITED AC 2008. [DOI: 10.3923/jas.2008.3060.3063] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Shin KC, Chung JH, Lee KH. Effects of TNF-alpha and leptin on weight loss in patients with stable chronic obstructive pulmonary disease. Korean J Intern Med 2007; 22:249-55. [PMID: 18309683 PMCID: PMC2687660 DOI: 10.3904/kjim.2007.22.4.249] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Weight loss is common in patients with chronic obstructive pulmonary disease (COPD). However, the mechanisms of this weight loss are still unclear. METHODS Sixty male patients with stable COPD and 45 healthy male controls participated in this study. The COPD patients were divided into two groups, that is, the emphysema and chronic bronchitis groups, by the transfer coefficient of carbon monoxide. The body composition, resting energy expenditure (REE), plasma leptin levels and serum tumor necrosis factor-alpha (TNF-alpha) were measured in all the study participants. The difference and correlation of these parameters were investigated between the two groups. RESULTS Emphysematous patients were characterized by a lower body mass index (BMI) and fat-mass (FM) compared with the chronic bronchitis patients (p < 0.001). The plasma leptin levels, as corrected for the FM, were not different between the COPD patients and healthy controls (78.3 +/- 30.9 pg/mL/kg vs. 70.9 +/- 17.3 pg/mL/kg, respectively), and the plasma leptin levels, as adjusted for the FM, were also not different between the two groups of COPD patients. In the chronic bronchitis patients, the plasma leptin concentration was correlated with the BMI (r = 0.866, p < 0.001) but it was not correlated with the BMI in the emphysema patients. The serum TNF-alpha levels were higher in the stable COPD patients than those in the controls, but there was no statistical difference (10.7 +/- 18.6 pg/mL vs. 7.2 x 3.5 pg/mL, respectively, p0.05). The leptin concentration was well correlated with the BMI and %FM in the patients with chronic bronchitis and the leptin concentration was only correlated with the %FM (r = 0.450, p = 0.027) in emphysema patients. There was no correlation between the plasma leptin concentration, as adjusted for the fat mass, and the activity of the TNF-alpha system. CONCLUSION The interaction of leptin and the activity of the TNF-alpha system in the pathogenesis of tissue depletion may not play an important role in chronic stable COPD patients.
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Affiliation(s)
- Kyeong-Cheol Shin
- Department of Internal Medicine, Yeungnam University, College of Medicine, Daegu, Korea
| | - Jin Hong Chung
- Department of Internal Medicine, Yeungnam University, College of Medicine, Daegu, Korea
| | - Kwan Ho Lee
- Department of Internal Medicine, Yeungnam University, College of Medicine, Daegu, Korea
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Tu T, Koski KG, Scott ME. Mechanisms underlying reduced expulsion of a murine nematode infection during protein deficiency. Parasitology 2007; 135:81-93. [PMID: 17908360 DOI: 10.1017/s0031182007003617] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Balb/c mice infected with the gastrointestinal nematode Heligmosomoides bakeri were fed protein sufficient (PS, 24%) or deficient (PD, 3%) diets to investigate whether diet, infection or dose of larval challenge (0, 100 or 200 larvae) influenced gut pathophysiology and inflammation. Among the PS mice, worms were more posteriorad in the intestine of mice infected with 200 compared with 100 larvae, suggesting active expulsion in the more heavily infected mice. This was consistent with the positive correlation between worm numbers and fluid leakage in PS mice; similar patterns were not detected in the PD mice. Infection also induced villus atrophy, which was more pronounced in PS than in PD mice. Our cytokine screening array indicated that infection in PD mice elevated a wide range of pro-inflammatory cytokines and chemokines. Whereas serum leptin concentrations were higher in PD mice, monocyte chemotactic protein-5 (MCP-5) in serum increased with increasing larval dose and concentrations were lower in PD than PS mice. We suggest that elevated MCP-5 together with villus atrophy may contribute to the apparent dose-dependent expulsion of H. bakeri from PS mice but that delayed expulsion in PD mice appeared related to a predominant Th1 cytokine profile that may be driven by leptin.
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Affiliation(s)
- T Tu
- School of Dietetics and Human Nutrition, McGill University (Macdonald Campus) 21, 111 Lakeshore Road, Ste-Anne de Bellevue, QC H9X 3V9, Canada
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Kitagawa J, Shingai T, Kajii Y, Takahashi Y, Taguchi Y, Matsumoto S. Leptin modulates the response to oleic acid in the pharynx. Neurosci Lett 2007; 423:109-12. [PMID: 17681693 DOI: 10.1016/j.neulet.2007.06.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Revised: 06/22/2007] [Accepted: 06/25/2007] [Indexed: 10/23/2022]
Abstract
Leptin released from the adipose tissues is known to inhibit obesity by regulating food intake. In this study, we investigated the effect of leptin on afferent nerve responses to fats and fatty acid in the pharyngolaryngeal region. The afferent nerve activities were recorded from the whole nerve bundle or pauci-fiber bundles of the pharyngeal branch of the glossopharyngeal nerve (GPN-ph) in Wistar normal and fatty rats. Oleic acid (long-chain fatty acid), mineral oil (nonfat oil) and safflower oil (vegetable oil; middle-chain fatty acid) were applied to the surface of pharyngolaryngeal mucous membrane. Oleic acid elicited vigorous stimulation of the GPN-ph activity in both normal and fatty rats but other oils had no significant effect on the activity. After intravenous administration of leptin (30 ng/kg, 1 ml), the response to oleic acid was significantly decreased in normal rats, whereas such a decrease was not found in fatty rats. These results are the first findings to indicate the existence of a suppressive mechanism of leptin on the response of the GPN-ph to fatty acid in normal rats, but that such a mechanism is lacking in fatty rats.
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Affiliation(s)
- Junichi Kitagawa
- Department of Physiology, Nippon Dental University, School of Life Dentistry at Tokyo, Tokyo 102-8159, Japan.
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Guven M, Bulut Y, Aladag I, Yelken K, Erdoğan H. Serum leptin levels in patients with nasal polyposis. The Journal of Laryngology & Otology 2007; 122:590-2. [PMID: 17625035 DOI: 10.1017/s002221510700967x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Nasal polyposis is one of the most common inflammatory pathologies of the nasal cavity. The aetiopathogenetic mechanisms of nasal polyp formation are still unclear. OBJECTIVES The aim of this study was to investigate the serum leptin levels in patients with nasal polyposis. DESIGN A randomised, prospective study was performed of 28 adult patients with nasal polyposis and 22 control subjects of a similar age, sex and body mass index. RESULTS Serum leptin levels were 12.10 +/- 9.39 ng/ml in the nasal polyposis patients and 6.17 +/- 7.68 ng/ml in the controls. A significant difference (p = 0.021) was observed in the mean serum leptin levels between nasal polyposis patients and controls. CONCLUSION Serum leptin levels were found to be significantly higher in patients with nasal polyposis. Leptin, apart from its primary role in the regulation of body weight and energy expenditure, may have a role in the inflammatory response of nasal polyposis.
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Affiliation(s)
- M Guven
- Department of ORL, Gaziosmanpaşa University, Tokat, Turkey.
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Abstract
Leptin, a hormone produced by adipocytes in proportion to fat stores, signals the sufficiency of energy reserves to the brain to control feeding and metabolism. Leptin represents a vital link between metabolic and neuroendocrine pathways, and adequate circulating leptin levels are required to permit the expenditure of energy on reproduction, growth, and other energy-intensive endocrine outputs. Leptin mediates its effects by acting upon a distributed network of CNS neurons that express the signaling form of the leptin receptor (LRb). Nutritional status early in development influences a lifelong metabolic program that modulates risk for diabetes, obesity and other elements of the metabolic syndrome. Recent evidence has demonstrated a number of important roles for leptin in the regulation of neural development and metabolic programming. In this review, we discuss leptin action, the neural circuits on which leptin acts, and our nascent understanding of how early leptin exposure may influence neural development and the predisposition to metabolic diseases.
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Affiliation(s)
- Gwendolyn W Louis
- Division of Metabolism, Endocrinology and Diabetes, Department of Medicine, University of Michigan Medical School, 5560 MSRB II/0678, 1150 W. Medical Center Dr., Ann Arbor, MI 48109, USA
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Dostalova I, Bartak V, Papezova H, Nedvidkova J. The effect of short-term exercise on plasma leptin levels in patients with anorexia nervosa. Metabolism 2007; 56:497-503. [PMID: 17379007 DOI: 10.1016/j.metabol.2006.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2006] [Accepted: 11/13/2006] [Indexed: 11/20/2022]
Abstract
Plasma leptin concentrations are markedly reduced in malnourished patients with anorexia nervosa (AN). Whether the long-term underweight and low-fat stores affect the leptin response to exercise remains unknown. We investigated the effect of 45-minute cycle ergometer exercise (2 W kg-1 of lean body mass [LBM]) on plasma leptin, norepinephrine (NE), glycerol, and insulin levels in 10 patients with AN and in 15 healthy age-matched women (C). Plasma leptin levels immediately and 90 minutes after the exercise bout were significantly reduced compared with basal leptin levels in both AN and C groups (P<.05). Compared with the control trial, leptin levels were significantly lower immediately and 90 minutes after exercise in the AN group (P<.05) but not in the C group. Basal and exercise-induced plasma glycerol and NE levels did not differ significantly between the groups. Basal and exercise-induced plasma insulin levels were significantly lower in the AN group compared with the C group (P<.05). In conclusion, we demonstrated that a single bout of low-intensity exercise significantly reduces plasma leptin levels in patients with AN. In healthy women, exercise had no effect on lowering leptin concentrations beyond the diurnal decrease that occurs in the absence of exercise. Neither NE nor insulin are responsible for the different response of leptin to exercise in AN.
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Affiliation(s)
- Ivana Dostalova
- Laboratory of Clinical and Experimental Neuroendocrinology, Institute of Endocrinology, 116 94 Prague 1, Czech Republic.
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Banno R, Arima H, Hayashi M, Goto M, Watanabe M, Sato I, Ozaki N, Nagasaki H, Ozaki N, Oiso Y. Central administration of melanocortin agonist increased insulin sensitivity in diet-induced obese rats. FEBS Lett 2007; 581:1131-6. [PMID: 17321524 DOI: 10.1016/j.febslet.2007.02.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2007] [Revised: 02/09/2007] [Accepted: 02/09/2007] [Indexed: 01/21/2023]
Abstract
In this study, we examined the effects of intracerebroventricular administration of melanotan II (MTII), a melanocortin agonist, on insulin sensitivity in diet-induced obese (DIO) rats. Although MTII treatment significantly decreased food intake and body weight for 10 days, there was no significant difference in body weight between MTII and pair-fed groups. The insulin tolerance test showed that insulin sensitivity was significantly improved in the MTII group compared to the pair-fed group. Furthermore, MTII treatment increased the number of small-sized adipocytes in epididymal white adipose tissues, suggesting that MTII increased insulin sensitivity through action on the white adipose tissues in DIO rats.
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Affiliation(s)
- Ryoichi Banno
- Department of Endocrinology and Diabetes, Field of Internal Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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35
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Stefanou N, Satra M, Papanikolaou V, Kalala F, Gatselis N, Germenis A, Dalekos GN, Tsezou A. Leptin receptor isoforms mRNA expression in peripheral blood mononuclear cells from patients with chronic viral hepatitis. Exp Biol Med (Maywood) 2006; 231:1653-63. [PMID: 17060687 DOI: 10.1177/153537020623101011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
There is accumulating evidence that leptin has a pleiotropic role in hematopoiesis, immune response, fibrogenesis, and hepatocarcinogenesis. We investigated the expression of leptin and leptin receptor (OB-R) at the protein level by flow cytometry and also quantified by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) the two major leptin receptor isoforms (OB-Rl, OB-Rs) in peripheral blood mononuclear cells (PBMCs) of patients with hepatitis B (HBV; n = 31), hepatitis C (HCV; n = 34), and nonviral liver disease (n = 25), and healthy controls (n = 36), as well as in liver tissues of HBV (n = 8), HCV (n = 7), and healthy individuals (n = 6). Serum leptin levels were measured in all participants (N = 126). We observed significantly lower OB-Rl and OB-Rs mRNA levels in PBMCs of HBV and HCV patients compared with healthy controls and nonviral liver disease patients (P < 0.05). Flow cytometry analysis confirmed the real-time RT-PCR results. Expression of leptin and OB-Rl was significantly increased in viral hepatitis liver tissues compared with healthy tissues (P < 0.01). OB-Rl mRNA levels were not associated with hepatitis patients' clinical status (inactive, chronic hepatitis, or cirrhosis). We also found decreased serum leptin in HBV and HCV patients compared with healthy individuals and the nonviral liver disease group. Leptin was expressed in 3 of 34 HCV (8.8%) and 19 of 25 (76%) nonviral liver disease patients. Moreover, expression of OB-Rl and OB-Rs were associated when all individuals were grouped together (r = 0.78, P < 0.001). In conclusion, our findings may suggest the involvement of the leptin system in the immunopathology of chronic viral hepatitis.
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MESH Headings
- Female
- Fibrosis/pathology
- Flow Cytometry
- Gene Expression Regulation
- Hepatitis B, Chronic/blood
- Hepatitis B, Chronic/genetics
- Hepatitis B, Chronic/physiopathology
- Hepatitis C, Chronic/blood
- Hepatitis C, Chronic/genetics
- Hepatitis C, Chronic/physiopathology
- Humans
- Leukocytes, Mononuclear/metabolism
- Liver Diseases/immunology
- Liver Diseases/pathology
- Liver Diseases/virology
- Middle Aged
- Protein Isoforms/blood
- Protein Isoforms/genetics
- RNA, Messenger/blood
- RNA, Messenger/genetics
- Receptors, Cell Surface/blood
- Receptors, Cell Surface/genetics
- Receptors, Leptin
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Nikolaos Stefanou
- University of Thessaly, Faculty of Health Sciences, Medical School, Department of Biology, 22 Papakyriazi Street, 41222 Larissa, Greece
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Paolucci M, Buono S, Sciarrillo R, Putti R. Effects of leptin administration on the endocrine pancreas and liver in the lizardPodarcis sicula. ACTA ACUST UNITED AC 2006; 305:383-95. [PMID: 16526046 DOI: 10.1002/jez.a.284] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this study, we investigated the presence of leptin receptor in pancreatic islets and the effect of exogenous leptin administration in Podarcis sicula on glucose metabolism. Our data show the presence of leptin receptor immunoreactivity in the endocrine pancreas suggesting that leptin may act at a peripheral level as previously postulated in mammals. The effects of short- and long-term and dose-response treatment with supraphysiological concentrations of leptin on circulating levels of insulin, glucagon and glucose in the blood have been evaluated. Taken together, our results indicate that leptin treatment was followed by an increase in insulin, glucagon and glucose in the blood, depending on the dose of leptin. Moreover, leptin treatment brought about a decrease of glycogen and the appearance of tyrosine-phosphorylated proteins in the liver. This study shows that in the lizard P. sicula leptin is involved in glucose metabolism.
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Affiliation(s)
- Marina Paolucci
- Department of Biological and Environmental Sciences, Faculty of Sciences, University of Sannio, Benevento, Italy.
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37
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38
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Adamowicz T, Flisikowski K, Starzyński R, Zwierzchowski L, Switoński M. Mutation in the Sp1 motif of the bovine leptin gene affects its expression. Mamm Genome 2006; 17:77-82. [PMID: 16416093 DOI: 10.1007/s00335-005-0068-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2005] [Accepted: 08/26/2005] [Indexed: 10/25/2022]
Abstract
Leptin is expressed mainly by adipocytes and plays a crucial role in the regulation of energy expenditure, food intake, and adiposity. Using PCR-heteroduplex analysis and sequencing, we investigated a C/G substitution in the promoter region of the bovine leptin gene. Application of the electrophoretic mobility shift assay showed that the C-->G transversion decreased the leptin gene promoter binding capacity for nuclear proteins. With real-time PCR and Western blotting, we showed that the leptin expression level was higher in cattle with the CC than with the GG genotype.
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Affiliation(s)
- Tatiana Adamowicz
- Department of Genetics and Animal Breeding, Agricultural University of Poznan, Poznan, Poland
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Yamada J, Sugimoto Y, Ujikawa M. Involvement of Leptin in Hypophagia Induced by the Serotonin Precursor 5-Hydroxytryptophan (5-HTP) in Mice. Biol Pharm Bull 2006; 29:557-9. [PMID: 16508167 DOI: 10.1248/bpb.29.557] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously demonstrated that a serotonin (5-HT) precursor 5-hydroxytryptophan (5-HTP) increases serum leptin levels in mice. It was reported that administration of 5-HTP elicits hypophagia in rodents and humans. In the present study, we examined involvement of leptin in 5-HTP-elicited decreases in the milk intake of fasted mice. Serum leptin levels increased with increases in milk intake in mice, while 5-HTP strongly decreased milk intake in fasted mice compared to that in the control group. Serum leptin levels in fasted mice treated with 5-HTP were similar to those control mice after milk intake. As leptin is a powerful anorectic signal, 5-HTP-induced anorexia may be mediated by facilitation of leptin secretion.
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Affiliation(s)
- Jun Yamada
- Department of Pharmacology, Kobe Pharmaceutical University, Japan.
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Aydemir O, Naziroğlu M, Colakoğlu N, Yilmaz T, Kükner A, Kükner AS. Leptin in corneas from keratoconus and infectious keratitis patients. J Ocul Pharmacol Ther 2005; 21:382-7. [PMID: 16245964 DOI: 10.1089/jop.2005.21.382] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
PURPOSE Leptin is produced primarily by adipose tissue. More recent studies have shown extra sites of leptin production in physiologic and ill human tissues. However, whether leptin originates from human corneas in infectious keratitis and keratoconus is not known. The aim of this study was to demonstrate and quantitate leptin expression in corneas with infectious keratitis and keratoconus and make comparisons to control corneas. METHODS We examined the immunohistochemical staining of leptin in nine corneas surgically excised from patients with infectious keratitis (3 patients), keratoconus (3 patients), and donor corneas (3 patients). RESULTS The results were analyzed using a semiquantitative scoring system of mild, moderate, and strong. Cells of the infectious keratitis group had the strongest leptin staining intensity, the control group had moderate, and the keratoconus group had mild staining intensity. The more vascular corneas in the infectious keratitis group were also associated with the greatest leptin staining. CONCLUSIONS Our findings indicate that leptin expression was present in all three sources of corneas (infectious keratitis, keratoconus, and normal control). Quantitative scoring would imply it may play a role in infectious keratitis, although further experiments are necessary to establish any causal relationship.
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Affiliation(s)
- Orhan Aydemir
- Department of Ophthalmology, Medicine Faculty, Firat University, Elazig, Turkey
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41
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Pocai A, Morgan K, Buettner C, Gutierrez-Juarez R, Obici S, Rossetti L. Central leptin acutely reverses diet-induced hepatic insulin resistance. Diabetes 2005; 54:3182-9. [PMID: 16249443 DOI: 10.2337/diabetes.54.11.3182] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Voluntary overfeeding rapidly induces resistance to the effects of systemic insulin and leptin on liver glucose metabolism. To examine whether central administration of recombinant leptin can restore leptin and insulin action on liver glucose fluxes, we infused leptin in the third cerebral ventricle of conscious overfed rats during pancreatic-insulin clamp studies. The effect of leptin on the phosphorylation of the signal transducer and activator of transcription-3 in the arcuate nuclei of the hypothalamus was similar in animals fed a regular diet or a high-fat diet for 3 days. The infusion of leptin in the third cerebral ventricle markedly inhibited glucose production in rats fed a high-fat diet mainly by decreasing glycogenolysis. The inhibition of glycogenolysis was sufficient to normalize glucose production and was accompanied by leptin-induced decreases in the hepatic expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase. Thus central administration of leptin rescues the hepatic insulin resistance induced by short-term hyperphagia.
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Affiliation(s)
- Alessandro Pocai
- Department of Medicine, Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Ayyildiz M, Yildirim M, Agar E, Baltaci AK. The effect of leptin on penicillin-induced epileptiform activity in rats. Brain Res Bull 2005; 68:374-8. [PMID: 16377445 DOI: 10.1016/j.brainresbull.2005.09.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 09/22/2005] [Accepted: 09/23/2005] [Indexed: 10/25/2022]
Abstract
Leptin is an adipose tissue-derived peptide hormone, which acts as a satiety factor to reduce appetite by interactions with hypothalamic neurons. The other possible physiological functions of leptin are still unclear. In this study, we have evaluated dose-dependent effect of leptin on penicillin-induced epileptiform activity, analyzed by electrocorticogram (ECoG). The epileptiform activity was induced by microinjection of penicillin into the left sensorymotor cortex. Thirty minutes after penicillin injection, 1, 2 or 10 microg of leptin was administrated intracerebroventricularly (i.c.v.). Leptin (1, 2 or 10 microg) alone did not significantly change the spike amplitudes in non-penicillin pretreated control animals. One or two micrograms of leptin significantly increased the frequency of epileptiform activity in the penicillin-pretreated animals. The high dose of leptin (10 microg) did not significantly change either amplitude or frequency of epileptiform activity. One microgram i.c.v. leptin was the most effective dose in changing of frequency on penicillin-induced epileptiform activity. The proconvulsant effects of leptin appeared 90 min after leptin (1 and 2 microg) injection. These data indicate that leptin increases the frequency of penicillin-induced epileptic activity. We speculate that this action of leptin might suggest that leptin may be a proconvulsant substance.
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Affiliation(s)
- Mustafa Ayyildiz
- Department of Physiology, Faculty of Medicine, University of Ondokuz Mayis, 55139 Samsun, Turkey
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Karakas S, Karadag F, Karul AB, Gurgey O, Gurel S, Guney E, Cildag O. Circulating leptin and body composition in chronic obstructive pulmonary disease. Int J Clin Pract 2005; 59:1167-70. [PMID: 16178984 DOI: 10.1111/j.1368-5031.2005.00567.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Nutritional depletion and weight loss are two features of chronic obstructive pulmonary disease (COPD), and the association between low body mass index (BMI) and poor prognosis in patients with COPD is a common clinical observation. Mechanisms of weight loss are still unclear in COPD. Excessive energy expenditure partly due to increased work of breathing was shown, but other mechanisms have been searched for. Leptin is a hormone secreted by adipocytes that plays an important role in energy homeostasis and regulates body weight through control of appetite and energy expenditure. The aim of this study was to evaluate the association of circulating leptin levels and measures of body composition in COPD patients. Thirty male COPD outpatients (mean age 66.3 +/- 8.4) and 20 controls (mean age 65.9 +/- 10.8) were included in the study. After standard spirometry and body composition measurements, serum leptin concentration was measured by ELISA assay. COPD patients were grouped according to BMI. Mean BMI was 19.01 +/- 2.26 kg/m2 in group 1 (COPD patients with low BMI), 26.85 +/- 4.51 in group 2 COPD (COPD patients with normal/high BMI) and 27.64 +/- 2.75 kg/m2 in healthy controls (group 3). Mean serum leptin concentration was 1.41 +/- 1.86 ng/ml in group 1, 2.60 +/- 1.38 ng/ml in group 2 and 2.82 +/- 1.46 ng/ml in group 3 (p = 0.002). Leptin correlated to not only BMI but also body weight, waist circumference, triceps and biceps skinfold thickness and body fat percent (p < 0.05 for all). Results of this study suggest that the cause of weight loss is not increased circulating leptin in COPD. Instead, leptin remains regulated in COPD and further decreased in patients with low BMI, probably as a compensatory mechanism to preserve body fat content, which should be evaluated in further studies.
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Affiliation(s)
- S Karakas
- Department of Anatomy, School of Medicine, Adnan Menderes University, Aydin, Turkey
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Schulze PC, Kratzsch J. Leptin as a new diagnostic tool in chronic heart failure. Clin Chim Acta 2005; 362:1-11. [PMID: 16005450 DOI: 10.1016/j.cccn.2005.05.019] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 05/16/2005] [Accepted: 05/17/2005] [Indexed: 01/21/2023]
Abstract
Leptin, the product of the ob-gene, regulates cellular homeostasis and glycemic control. While initially described as an adipocyte-derived protein with expression and secretion restricted to adipose tissue, recent reports have shown local expression of leptin in several tissues including the skeletal muscle, heart, vessels and brain. Leptin acts through the different isoforms of its receptor which are ubiquitously expressed and can be detected in endothelium, vascular smooth muscle and myocardium. In addition to its metabolic effects, leptin has distinct effects in the cardiovascular system leading to increased production of proinflammatory cytokines and oxidative stress, vascular remodeling and neointima formation as well as cardiomyocyte hypertrophy. Notably, recent clinical studies have linked serum levels of leptin to the occurrence of cardiovascular events such as myocardial infarction and stroke suggesting that leptin promotes pro-atherogenic vascular mechanisms. In contrast, less is known about the role and effects of leptin in the setting of chronic heart failure. We here review the current knowledge on cardiovascular effects of leptin and discuss its potential as a new therapeutic tool in chronic heart failure.
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Affiliation(s)
- P Christian Schulze
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02139, USA.
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Lin HY, Xu Q, Yeh S, Wang RS, Sparks JD, Chang C. Insulin and leptin resistance with hyperleptinemia in mice lacking androgen receptor. Diabetes 2005; 54:1717-25. [PMID: 15919793 DOI: 10.2337/diabetes.54.6.1717] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Epidemiological evidence suggests that sex differences exist in type 2 diabetes. Men seem to be more susceptible than women to the consequences of obesity and sedentary lifestyle, possibly because of differences in insulin sensitivity and regional body fat deposition. Thus, lacking androgen receptor (AR) in male individuals may promote insulin resistance. To determine whether lacking AR in male individuals contributes to in vivo insulin resistance, an AR knockout model (AR(-/y)) was used to study the correlation between AR and insulin resistance. Progressive reduced insulin sensitivity and impaired glucose tolerance were seen in AR(-/y) mice with advancing age. Aging AR(-/y) mice displayed accelerated weight gain, hyperinsulinemia, and hyperglycemia, and loss of AR contributes to increased triglyceride content in skeletal muscle and liver. Leptin is higher in serum of AR(-/y) mice. Treatment with exogenous leptin fails to stimulate weight loss in AR(-/y) mice in advanced age, suggesting leptin resistance in the AR(-/y/) mice. Exogenous dihydrotestosterone replacement fails to reverse the metabolic abnormalities and insulin resistance in AR(-/y) mice. Our in vivo studies demonstrate that androgen-AR plays key roles in the development of insulin and leptin resistance, which may contribute to the development of type 2 diabetes and cardiovascular disease.
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Affiliation(s)
- Hung-Yun Lin
- Department of Pathology, Urology, Radiation Oncology, and the Cancer Center, 601 Elmwood Ave., Box 626, Rochester, NY 14642, USA
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Büyükgebiz B, Oztürk Y, Yilmaz S, Arslan N. Serum leptin concentrations in children with mild protein-energy malnutrition and catch-up growth. Pediatr Int 2004; 46:534-8. [PMID: 15491379 DOI: 10.1111/j.1442-200x.2004.01951.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The aim of the present study was to clarify the relationship between changing nutritional anthropometric data and serum leptin concentrations during the catch-up growth process in children. METHODS Thirty children with mild protein-energy malnutrition (PEM) were followed for 6 months and their anthropometric measurements and serum leptin concentrations were recorded during follow up. RESULTS Twenty-two (73.3%) of the 30 children showed catch-up growth. All parameters and serum leptin concentrations increased during the period of catch-up growth. In the remaining eight children, weight for height, percentage standard body mass index, percentage standard body height and mean serum leptin concentrations did not show any significant increase at the 6 month follow-up. Mean serum leptin concentration was higher in children with catch-up growth than in the controls. CONCLUSION During recovery from malnutrition, leptin concentrations increase in relation to fat mass if the fat mass reaches a critical point, and leptin might trigger catch-up growth with its regulator effects on growth. Although weight gain was noted in both groups, an increase in leptin concentration was observed only in children who showed catch-up growth. More interestingly, the mean leptin concentration was much higher in children with PEM who had catch-up growth compared to the control group and in children who failed to have catch-up growth. In children with catch-up growth, the higher serum leptin concentrations compared to healthy children and to children without catch-up growth despite significant weight gain suggests that leptin affects nutritional status in catch-up growth as a dynamic process, rather than merely being an index of body fat content.
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Affiliation(s)
- Benal Büyükgebiz
- Department of Pediatric Gastroenterology, Metabolism and Nutrition, Faculty of Medicine, Dokuz Eylül University, Inciralti, Izmir, Turkey
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How adipocytes integrate surplus caloric intake with caloric storage: lessons from Morgan Spurlock and some French geese. ACTA ACUST UNITED AC 2004. [DOI: 10.1097/01.med.0000143457.37548.7e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hamrick MW. Leptin, bone mass, and the thrifty phenotype. J Bone Miner Res 2004; 19:1607-11. [PMID: 15355554 DOI: 10.1359/jbmr.040712] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2004] [Revised: 04/21/2004] [Accepted: 05/21/2004] [Indexed: 12/20/2022]
Affiliation(s)
- Mark W Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, Georgia, USA.
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Guler N, Kirerleri E, Ones U, Tamay Z, Salmayenli N, Darendeliler F. Leptin: does it have any role in childhood asthma? J Allergy Clin Immunol 2004; 114:254-9. [PMID: 15316499 DOI: 10.1016/j.jaci.2004.03.053] [Citation(s) in RCA: 172] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Although there is evidence of a positive association between asthma and obesity in adults and children, very little is known about the role of leptin in asthmatic children. OBJECTIVES The aims of this study were to evaluate the relation between leptin and parameters of atopy and asthma in children. METHODS Body mass index (BMI) and serum leptin levels were measured in 102 (37 female, 65 male; mean age, 5.9 +/- 3.4 years) asthmatic and 33 (14 female, 19 male; mean age, 6.1 +/- 3.4 years) healthy children. Skin prick tests, total serum IgE, and pulmonary function tests were performed and were completed. RESULTS A significant difference was observed in serum leptin levels between asthmatic and healthy children. Median (interquartile range) levels were 3.53 (2.06-7.24) ng/mL and 2.26 (1.26-4.71) ng/mL, respectively (P=.008). Subgroup analysis revealed that this difference in leptin levels was confined entirely to boys: 3.09 (1.99-7.51) ng/mL in boys with asthma versus 1.52 (1.06-3.17) ng/mL in boys without asthma (P=.003). By logistic regression analysis, we found that leptin was a predictive factor for having asthma (odds ratio, 1.98; CI, 1.10-3.55; P=.021), whereas sex, age, or BMI were not. In a stepwise multiple regression analysis including sex (P=.001), age (P=.016), BMI (P <.001), and asthma (P=.022), all of these variables were found to affect log leptin levels (R2=0.404). There was no significant sex difference in serum leptin levels among asthmatic children, whereas healthy boys had significantly lower leptin levels than healthy girls (P=.019). Atopic asthmatic subjects had significantly higher leptin levels than nonatopic asthmatic subjects (P=.038) with similar BMI. A significant, but weak, correlation was observed between leptin levels and IgE in the overall group of asthmatic children (r=0.231; P=.019). Again, this correlation was confined entirely to boys (r=0.319; P=.010). There was no relation between leptin levels and skin prick tests, pulmonary function tests, passive smoking, birth weight, and duration of breast-feeding. CONCLUSION Our findings suggest that leptin may play a role in atopic asthma. High serum leptin levels in asthmatic boys may partly explain the higher prevalence of childhood asthma in male sex.
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Affiliation(s)
- Nermin Guler
- Department of Pediatrics, Division of Allergy and Chest Diseases, Istanbul Medical Faculty, Turkey.
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Francis J, MohanKumar SMJ, MohanKumar PS. Leptin inhibits norepinephrine efflux from the hypothalamus in vitro: role of gamma aminobutyric acid. Brain Res 2004; 1021:286-91. [PMID: 15342279 DOI: 10.1016/j.brainres.2004.07.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2004] [Indexed: 11/24/2022]
Abstract
Leptin, a hormone secreted by adipocytes, produces a number of central and neuroendocrine effects, the mechanisms behind which are not completely understood. Hypothalamic norepinephrine (NE) is involved in many of the neuroendocrine effects that are associated with leptin. Therefore, we hypothesized that leptin could affect hypothalamic NE activity to bring about its central and neuroendocrine effects. Because gamma aminobutyric acid (GABA) is known to affect the release of NE, we also tested the possibility that leptin-induced changes in NE could be mediated through GABA. The mediobasal hypothalami from adult male rats were incubated in an in vitro incubation system for four consecutive incubation periods of 60 min each at 37 degrees C in Krebs Ringers Henseleit (KRH) solution in an atmosphere of 95% O(2) and 5% CO(2.) After determining the basal release, the hypothalami were challenged with 0, 0.1, 1 or 10 nm of leptin, bicuculline (a GABA-A receptor antagonist; 10 microM) and bicuculline (10 microM) +10 nM of leptin during the second incubation period. Residual effects of leptin were measured in the third incubation where tissues were incubated with KRH alone, and the viability of tissues was determined in the fourth incubation when tissues were exposed to high K(+) KRH. NE levels in the incubation medium were measured using high-performance liquid chromatography with electrochemical detection (HPLC-EC). Leptin inhibited NE efflux from the hypothalamus in a dose-dependent manner. Moreover, incubation of hypothalami with 10 nM of leptin and bicuculline, a completely blocked the leptin-induced decrease in NE efflux. These results demonstrate for the first time that leptin could act directly on the hypothalamus to inhibit NE efflux through GABA. It was concluded that leptin could probably produce its central and neuroendocrine effects by modulating NE and GABA levels in the hypothalamus.
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Affiliation(s)
- Joseph Francis
- Neuroendocrine Research Laboratory, Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, A 522 East Fee Hall, East Lansing, MI 48824, USA
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