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Chen Y, Wang G, Chen J, Wang C, Dong X, Chang HM, Yuan S, Zhao Y, Mu L. Genetic and Epigenetic Landscape for Drug Development in Polycystic Ovary Syndrome. Endocr Rev 2024; 45:437-459. [PMID: 38298137 DOI: 10.1210/endrev/bnae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/26/2023] [Accepted: 01/23/2024] [Indexed: 02/02/2024]
Abstract
The treatment of polycystic ovary syndrome (PCOS) faces challenges as all known treatments are merely symptomatic. The US Food and Drug Administration has not approved any drug specifically for treating PCOS. As the significance of genetics and epigenetics rises in drug development, their pivotal insights have greatly enhanced the efficacy and success of drug target discovery and validation, offering promise for guiding the advancement of PCOS treatments. In this context, we outline the genetic and epigenetic advancement in PCOS, which provide novel insights into the pathogenesis of this complex disease. We also delve into the prospective method for harnessing genetic and epigenetic strategies to identify potential drug targets and ensure target safety. Additionally, we shed light on the preliminary evidence and distinctive challenges associated with gene and epigenetic therapies in the context of PCOS.
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Affiliation(s)
- Yi Chen
- Reproductive Medicine Center, Zhongshan Hospital, Fudan University, Shanghai 200032, China
- The First School of Medicine, Wenzhou Medical University, Wenzhou 325035, China
| | - Guiquan Wang
- Department of Reproductive Medicine, Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen 361003, China
- Xiamen Key Laboratory of Reproduction and Genetics, Xiamen University, Xiamen 361023, China
| | - Jingqiao Chen
- The First School of Medicine, Wenzhou Medical University, Wenzhou 325035, China
| | - Congying Wang
- The Department of Cardiology, The Fourth Affiliated Hospital of Zhejiang University School of Medicine, Zhejiang 322000, China
| | - Xi Dong
- Reproductive Medicine Center, Zhongshan Hospital, Fudan University, Shanghai 200032, China
| | - Hsun-Ming Chang
- Department of Obstetrics and Gynecology, China Medical University Hospital, Taichung 40400, Taiwan
| | - Shuai Yuan
- Unit of Cardiovascular and Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institute, Stockholm 171 65, Sweden
| | - Yue Zhao
- State Key Laboratory of Female Fertility Promotion, Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China
- National Clinical Research Center for Obstetrics and Gynecology, Beijing 100007, China
- Key Laboratory of Assisted Reproduction, Ministry of Education, Peking University, Beijing 100191, China
- Beijing Key Laboratory of Reproductive Endocrinology and Assisted Reproductive Technology, Peking University, Beijing 100191, China
| | - Liangshan Mu
- Reproductive Medicine Center, Zhongshan Hospital, Fudan University, Shanghai 200032, China
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Lei X, Zhou Q, Wang Y, Fu S, Li Z, Chen Q. Serum and supplemental vitamin D levels and insulin resistance in T2DM populations: a meta-analysis and systematic review. Sci Rep 2023; 13:12343. [PMID: 37524765 PMCID: PMC10390579 DOI: 10.1038/s41598-023-39469-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 07/26/2023] [Indexed: 08/02/2023] Open
Abstract
Observational studies have shown a negative correlation between Vitamin D level and the likelihood of developing insulin resistance (IR) and/or diabetes over time, yet evidence remains inconsistent. In this meta-analysis and systematic review, we strive to define the potential association between serum or supplemental Vitamin D Levels and insulin resistance respectively, as well as the contribution of Vitamin D to type 2 diabetes, and to summarize the biologic plausibility of Vitamin D. Four databases (PubMed, Embase, Cochrane Library, and Web of Science) were searched for this Systematic Literature Review (SLR) to find appropriate observational studies and clinical trials published in English through to July 2022. EndNote (version X9) is used to manage the literature search results. We calculated Standard Mean Differences (SMDs) and Risk Ratios (RRs) with their 95% Confidence Intervals (CIs), separately, for continuous and dichotomous outcomes. The correlation coefficients were normalized to z values through Fisher's z-transformation to calculate the relevant statistics. Meta-analyses were carried out for all comparisons, based on a random-effects pooling model. Data analysis was performed using RevMan (version 5.3) and STATA (version 15.1). All statistical tests were two-sided, with P < 0.05 were regarded as significant. In our current meta-analysis, there are 18 RCTs and 20 observational studies including 1243 and 11,063 participants respectively. In the overall analysis, the diabetic with Vitamin D supplement treatment group showed significantly improve serum insulin (SMD = - 0.265, 95% CI - 0.394 to - 0.136, P < 0.05), glucose (SMD = - 0.17, 95% CI - 0.301to - 0.039, P < 0.05) and HOMA-IR (SMD = - 0.441, 95% CI - 0.582 to - 0.3, P < 0.05) compared with the routine treatment group. Correlation analysis results showed that all three outcomes were significantly correlated in a negative manner with raised Vitamin D (insulin: r = - 0.08 95% = - 0.12 to - 0.04; glucose: r = - 0.06 95% = - 0.11 to - 0.01; HOMA-IR: r = - 0.08 95% = - 0.09 to - 0.06). Results of overall analysis proved that vitamin D has shown significant effect on regulates insulin resistance, and there is a significant inverse association between serum Vitamin D level and IR. Vitamin D supplementation is expected to be integrated into conventional medical approaches to prevent type 2 diabetes and to mitigate the burden of diabetes for individuals and society.PROSPERO registration number: CRD42022348295.
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Affiliation(s)
- Xingxing Lei
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, Sichuan, China
| | - Qian Zhou
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, Sichuan, China
| | - Yanmei Wang
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, Sichuan, China
| | - Shunlian Fu
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, Sichuan, China
| | - Zinan Li
- Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, 610072, Sichuan, China
| | - Qiu Chen
- Hospital of Chengdu University of Traditional Chinese Medicine, Sichuan Province, No. 39, Shi-er-Qiao Road, Chengdu, 610072, People's Republic of China.
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Zhai Z, Deng Y, He Y, Chen L, Chen X, Zuo L, Liu M, Mao M, Li S, Hu H, Chen H, Wei Y, Zhou Q, Hao G, Peng S. Association between serum calcium level and type 2 diabetes: An NHANES analysis and Mendelian randomization study. Diabet Med 2023:e15080. [PMID: 36883871 DOI: 10.1111/dme.15080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/09/2023]
Abstract
AIMS This study investigated the association between serum calcium levels and the prevalence of T2D using a cross-sectional study and Mendelian randomization analysis. METHODS Cross-sectional data were obtained from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018. Serum calcium levels were divided into three groups (low, medium and high groups) according to the tertiles. Logistic regression was used to estimate the association between serum calcium levels and T2D prevalence. Instrumental variables for serum calcium levels were obtained from the UK Biobank and a two-sample MR analysis was performed to examine the causal relationship between genetically predicted serum calcium levels and the risk of T2D. RESULTS A total of 39,645 participants were available for cross-sectional analysis. After adjusting for covariates, participants in the high serum calcium group had significantly higher odds of T2D (OR = 1.18, 95% CI = 1.07, 1.30, p = 0.001) than those in the moderate group. Restricted cubic spline plots showed a J-shaped curve relationship between serum calcium level and prevalence of T2D. Consistently, Mendelian randomization analysis showed that higher genetically predicted serum calcium levels were causally associated with a higher risk of T2D (OR = 1.16, 95% CI: 1.01, 1.33, p = 0.031). CONCLUSIONS The results of this study suggest that higher serum calcium levels are causally associated with a higher risk of T2D. Further studies are needed to clarify whether intervening in high serum calcium could reduce the risk of T2D.
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Affiliation(s)
- Zhiyu Zhai
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Yun Deng
- Community Health Service Center of Xiagang Street, Guangzhou, China
| | - Yunbiao He
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Li Chen
- Department of Medicine, Medical College of Georgia, Georgia Prevention Institute, Augusta University, Augusta, Georgia, USA
| | - Xia Chen
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Lei Zuo
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Mingliang Liu
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, China
| | - Minzhi Mao
- Community Health Service Center of Xiagang Street, Guangzhou, China
| | - Sha Li
- Community Health Service Center of Xiagang Street, Guangzhou, China
| | - Haiping Hu
- Community Health Service Center of Xiagang Street, Guangzhou, China
| | - Haiyan Chen
- Department of Parasitic Disease and Endemic Disease Control and Prevention, Guangzhou Center for Disease Control and Prevention, Guangzhou, China
| | - Yuan Wei
- Key Laboratory of Sports Technique, Tactics and Physical Function of General Administration of Sport of China, Guangzhou Sport University, Guangzhou, China
| | - Qin Zhou
- Guangzhou Center for Disease Control and Prevention, Guangzhou, China
| | - Guang Hao
- Department of Public Health and Preventive Medicine, School of Medicine, Jinan University, Guangzhou, China
- Guangdong Key Laboratory of Environmental Exposure and Health, Jinan University, Guangzhou, China
| | - Shuang Peng
- School of Sport and Health Sciences, Guangzhou Sport University, Guangzhou, China
- Key Laboratory of Sports Technique, Tactics and Physical Function of General Administration of Sport of China, Scientific Research Center, Guangzhou Sport University, Guangzhou, China
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Cowan S, Lim S, Alycia C, Pirotta S, Thomson R, Gibson-Helm M, Blackmore R, Naderpoor N, Bennett C, Ee C, Rao V, Mousa A, Alesi S, Moran L. Lifestyle management in polycystic ovary syndrome - beyond diet and physical activity. BMC Endocr Disord 2023; 23:14. [PMID: 36647089 PMCID: PMC9841505 DOI: 10.1186/s12902-022-01208-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 11/09/2022] [Indexed: 01/18/2023] Open
Abstract
Polycystic ovary syndrome (PCOS) is a common condition affecting reproductive-aged women with reproductive, metabolic and psychological consequences. Weight and lifestyle (diet, physical activity and behavioural) management are first-line therapy in international evidence-based guidelines for PCOS. While these recommend following population-level diet and physical activity guidelines, there is ongoing interest and research in the potential benefit of including psychological and sleep interventions, as well as a range of traditional, complimentary and integrative medicine (TCIM) approaches, for optimal management of PCOS. There is limited evidence to recommend a specific diet composition for PCOS with approaches including modifying protein, carbohydrate or fat quality or quantity generally having similar effects on the presentations of PCOS. With regards to physical activity, promising evidence supports the provision of vigorous aerobic exercise, which has been shown to improve body composition, cardiorespiratory fitness and insulin resistance. Psychological and sleep interventions are also important considerations, with women displaying poor emotional wellbeing and higher rates of clinical and subclinical sleep disturbance, potentially limiting their ability to make positive lifestyle change. While optimising sleep and emotional wellbeing may aid symptom management in PCOS, research exploring the efficacy of clinical interventions is lacking. Uptake of TCIM approaches, in particular supplement and herbal medicine use, by women with PCOS is growing. However, there is currently insufficient evidence to support integration into routine clinical practice. Research investigating inositol supplementation have produced the most promising findings, showing improved metabolic profiles and reduced hyperandrogenism. Findings for other supplements, herbal medicines, acupuncture and yoga is so far inconsistent, and to reduce heterogeneity more research in specific PCOS populations, (e.g. defined age and BMI ranges) and consistent approaches to intervention delivery, duration and comparators are needed. While there are a range of lifestyle components in addition to population-recommendations for diet and physical activity of potential benefit in PCOS, robust clinical trials are warranted to expand the relatively limited evidence-base regarding holistic lifestyle management. With consumer interest in holistic healthcare rising, healthcare providers will be required to broaden their knowledge pertaining to how these therapies can be safely and appropriately utilised as adjuncts to conventional medical management.
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Affiliation(s)
- Stephanie Cowan
- Monash Centre for Health Research and Implementation, Monash University, Clayton, Victoria, Australia.
| | - Siew Lim
- Eastern Health Clinical School, Monash University, Box Hill, Victoria, Australia
| | - Chelsea Alycia
- Monash Centre for Health Research and Implementation, Monash University, Clayton, Victoria, Australia
| | - Stephanie Pirotta
- Health and Social Care Unit, Monash University, Clayton, Victoria, Australia
| | - Rebecca Thomson
- Robinson Research Institute, The University of Adelaide, North Adelaide, South Australia, Australia
| | - Melanie Gibson-Helm
- Monash Centre for Health Research and Implementation, Monash University, Clayton, Victoria, Australia
- Te Tātai Hauora o Hine - National Centre for Women's Health Research Aotearoa, Te Herenga Waka - Victoria University of Wellington, Wellington, New Zealand
| | - Rebecca Blackmore
- Centre for Mental Health, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Negar Naderpoor
- Monash Centre for Health Research and Implementation, Monash University, Clayton, Victoria, Australia
| | - Christie Bennett
- Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Victoria, Australia
| | - Carolyn Ee
- NICM Health Research Institute, Western Sydney University, Westmead, New South Wales, Australia
| | - Vibhuti Rao
- NICM Health Research Institute, Western Sydney University, Westmead, New South Wales, Australia
| | - Aya Mousa
- Monash Centre for Health Research and Implementation, Monash University, Clayton, Victoria, Australia
| | - Simon Alesi
- Monash Centre for Health Research and Implementation, Monash University, Clayton, Victoria, Australia
| | - Lisa Moran
- Monash Centre for Health Research and Implementation, Monash University, Clayton, Victoria, Australia
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Mathiesen DS, Lund A, Holst JJ, Knop FK, Lutz TA, Bagger JI. THERAPY OF ENDOCRINE DISEASE: Amylin and calcitonin - physiology and pharmacology. Eur J Endocrinol 2022; 186:R93-R111. [PMID: 35353712 DOI: 10.1530/eje-21-1261] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 03/30/2022] [Indexed: 11/08/2022]
Abstract
Type 2 diabetes is a common manifestation of metabolic dysfunction due to obesity and constitutes a major burden for modern health care systems, in concert with the alarming rise in obesity worldwide. In recent years, several successful pharmacotherapies improving glucose metabolism have emerged and some of these also promote weight loss, thus, ameliorating insulin resistance. However, the progressive nature of type 2 diabetes is not halted by these new anti-diabetic pharmacotherapies. Therefore, novel therapies promoting weight loss further and delaying diabetes progression are needed. Amylin, a beta cell hormone, has satiating properties and also delays gastric emptying and inhibits postprandial glucagon secretion with the net result of reducing postprandial glucose excursions. Amylin acts through the six amylin receptors, which share the core component with the calcitonin receptor. Calcitonin, derived from thyroid C cells, is best known for its role in humane calcium metabolism, where it inhibits osteoclasts and reduces circulating calcium. However, calcitonin, particularly of salmon origin, has also been shown to affect insulin sensitivity, reduce the gastric emptying rate and promote satiation. Preclinical trials with agents targeting the calcitonin receptor and the amylin receptors, show improvements in several parameters of glucose metabolism including insulin sensitivity and some of these agents are currently undergoing clinical trials. Here, we review the physiological and pharmacological effects of amylin and calcitonin and discuss the future potential of amylin and calcitonin-based treatments for patients with type 2 diabetes and obesity.
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Affiliation(s)
- David S Mathiesen
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
| | - Asger Lund
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
- Department of Medicine, Gentofte and Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip K Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
- Department of Medicine, Gentofte and Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse-Faculty, University of Zurich, Zurich, Switzerland
| | - Jonatan I Bagger
- Center for Clinical Metabolic Research, Gentofte Hospital, Hellerup, Denmark
- Department of Medicine, Gentofte and Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
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Hajhashemy Z, Rouhani P, Saneei P. Dietary calcium intake in relation to type-2 diabetes and hyperglycemia in adults: A systematic review and dose-response meta-analysis of epidemiologic studies. Sci Rep 2022; 12:1050. [PMID: 35058558 PMCID: PMC8776796 DOI: 10.1038/s41598-022-05144-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 12/30/2021] [Indexed: 11/09/2022] Open
Abstract
Several epidemiological studies investigated the relation of Ca intake with type 2 diabetes mellitus (T2DM), but there were inconsistencies in their findings. So, we conducted a systematic review and dose-response meta-analysis to quantify the relation of dietary Ca intake with the risk of T2DM/hyperglycemia in adults. A systematic search was conducted up to May 2021, in MEDLINE (Pubmed), Web of Science (WOS), Scopus electronic databases and Google Scholar, for epidemiological studies that investigated the relation of dietary Ca intake (as the exposure) and T2DM/hyperglycemia (as the outcome) in adults, without restriction in publication date and language. Finally, 8 cohort and 9 cross-sectional studies were included in the analysis. The body of evidence was assessed by the GRADE approach. Combining effect sizes from prospective cohort studies included 255,744 general adult population illustrated that highest level of dietary Ca intake, compared to lowest category, was related to an 18% reduced risk of T2DM (RR: 0.82; 95% CI 0.74-0.92). Based on linear dose-response analysis (including 255,744 healthy individuals and 13,531 patients with T2DM), each 300, 600 and 1000 mg/day increment in dietary Ca intake was respectively associated to 7, 14 and 23% reduced risk of T2DM. There was a steeper reduction in risk of T2DM when dietary Ca intake increased from low levels to 750 mg/day. Nevertheless, meta-analysis of cross-sectional studies revealed an inverse significant association between dietary Ca intake and T2DM/hyperglycemia only in the female population (OR: 0.66; 95% CI 0.50-0.88). This meta-analysis illustrated an inverse association between dietary Ca intake and risk of T2DM in general adult populations in prospective cohort studies, in a dose-response manner. It seems that increasing dietary Ca intake from low levels to around 750 mg/day was inversely related to risk of T2DM. In cross-sectional studies, an inverse relation between dietary Ca intake and T2DM/hyperglycemia was found only in females.
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Affiliation(s)
- Zahra Hajhashemy
- Students' Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran.,Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, PO Box 81745-151, Isfahan, Iran
| | - Parisa Rouhani
- Students' Research Committee, Isfahan University of Medical Sciences, Isfahan, Iran.,Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, PO Box 81745-151, Isfahan, Iran
| | - Parvane Saneei
- Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, PO Box 81745-151, Isfahan, Iran.
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A Clinician’s guide to vitamin D supplementation for patients with cystic fibrosis. J Clin Transl Endocrinol 2021; 26:100273. [PMID: 34815946 PMCID: PMC8593649 DOI: 10.1016/j.jcte.2021.100273] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 10/14/2021] [Accepted: 10/26/2021] [Indexed: 11/20/2022] Open
Abstract
Vitamin D deficiency is multifactorial in the cystic fibrosis population. Vitamin D deficiency can adversely affect multiple organ systems in the cystic fibrosis population. In the cystic fibrosis population in the United States, we aim to treat to serum 25-hydroxyvitamin D levels over 30 ng/ml. Cholecalciferol is used in preference to ergocalciferol. Daily or once weekly dosing regimens are chosen according to patient preference and compliance.
Vitamin D deficiency is common in the general population, and even more so in patients with cystic fibrosis. Deficiency is exacerbated in cystic fibrosis patients because of a myriad of causes including malabsorption, decreased fat mass, reduced 25-hydroxylation of vitamin D, reduced exposure to sunlight, decreased vitamin D binding protein, and exposure to drugs that increase catabolism. In turn, vitamin D deficiency can contribute to poor bone health. Additionally, it may contribute to pulmonary decline in the form of worsening pulmonary function, increased colonization with pathogens, and increased pulmonary exacerbation. Because vitamin D deficiency is correlated with negative clinical effects in multiple organ systems of patients with cystic fibrosis, it is important to screen for and treat deficiency in these patients. The Cystic Fibrosis Foundation has issued guidelines for the treatment of vitamin D deficiency, targeting serum levels of 25-hydroxyvitamin D of at least 30 ng/ml. The guidelines offer age-specific escalating dose regimens depending on serum vitamin D levels, with monitoring at 12- week intervals after changing therapy. They address the literature on alternative vitamin D sources, such as UV lamps, ideal formulations (cholecalciferol in preference to ergocalciferol), and optimal vehicles of administration. Despite these detailed recommendations, most centers are still unable to achieve in-target serum vitamin D levels for many of their patients. Future research examining ideal treatment regimens to achieve serum targets and maximize clinical effects are needed. Moreover, it is unknown whether vitamin D sufficiency will be easier to achieve on new triple therapy cystic fibrosis drug combinations, and how these drugs will contribute to vitamin D-related clinical outcomes.
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Jamshidi M, Mohammadi Pour S, Bahadoram M, Mahmoudian-Sani MR, Saeedi Boroujeni A. Genetic polymorphisms associated with polycystic ovary syndrome among Iranian women. Int J Gynaecol Obstet 2020; 153:33-44. [PMID: 33314055 DOI: 10.1002/ijgo.13534] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/05/2020] [Accepted: 12/09/2020] [Indexed: 12/27/2022]
Abstract
Polycystic ovary syndrome (PCOS) involves abnormalities in ovarian, reproductive, and metabolic systems. Genetic polymorphisms associated with individual differences and variations might be related to complex disorders with unknown causes, including PCOS. Several leading genetic markers with known cellular functions have been identified among Iranian women presenting with PCOS. In particular, the existing evidence shows a significant relationship between PCOS and the following genetic polymorphisms: rs2275913 (interleukin-17A), rs9927163 (interleukin-32), Pro12Ala (peroxisome proliferator-activated receptor-γ), rs17173608 (chemerin), rs2236242 (vaspin), ApaI (vitamin D receptor), and rs7895833 (sirtuin 1). In addition, a higher risk of PCOS is associated with the rs2910164 (microRNA 146a), rs2241766 (adiponectin), -34 T/C (cytochrome 17), and rs1800682 (Fas) polymorphisms. Furthermore, protective effects against PCOS have been reported for the A4223C polymorphism of adenosine deaminase 1. Overall, the available data indicate that Iranian women with PCOS have a higher prevalence of polymorphisms in inflammation- and metabolism-related genes, but not in insulin-related genes. More extensive studies are needed to identify the ethnicity-related genetic associations in PCOS.
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Affiliation(s)
- Mohammad Jamshidi
- Department of Laboratory Sciences, School of Allied Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Somayeh Mohammadi Pour
- Department of Obstetrics and Gynecology, School of Medicine Lorestan, University of Medical Sciences, Khorramabad, Iran
| | - Mohammad Bahadoram
- Thalassemia and Hemoglobinopathy Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Mohammad-Reza Mahmoudian-Sani
- Thalassemia and Hemoglobinopathy Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Ali Saeedi Boroujeni
- Department of Immunology, Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.,ImmunologyToday, Universal Scientific Education and Research Network, Tehran, Iran
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Günalan E, Yaba A, Yılmaz B. The effect of nutrient supplementation in the management of polycystic ovary syndrome-associated metabolic dysfunctions: A critical review. J Turk Ger Gynecol Assoc 2018; 19:220-232. [PMID: 30299265 PMCID: PMC6250088 DOI: 10.4274/jtgga.2018.0077] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Polycystic ovary syndrome (PCOS) is complex heterogeneous disorder that has several aspects in terms of pathology such as metabolic, endocrine, reproductive, and psychological. However, the etiology of PCOS remains poorly understood. Several studies suggest that insulin resistance and hyperandrogenism play a central role in the progression of PCOS pathophysiology. Therefore, common treatment strategies of PCOS are based on lifestyle modification, which include exercise, diet, and nutrient supplementation therapy. Recent studies have recommended some nutrients such as vitamins, minerals, and vitamin-like nutrients for the therapy of PCOS because each has at least one functional property in PCOS-induced pathways. Therefore, it is claimed that the cause of PCOS could be vitamin or mineral deficiency. This review aims to provide a critical literature survey on nutritional supplementation for the treatment of PCOS-associated endocrine and metabolic dysfunctions and discuss the role of nutrients in the management of PCOS in view of the clinical trials and experimental studies.
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Affiliation(s)
- Elif Günalan
- Department of Physiology, Yeditepe University School of Medicine, İstanbul, Turkey
| | - Aylin Yaba
- Department of Histology and Embryology, Yeditepe University School of Medicine, İstanbul, Turkey
| | - Bayram Yılmaz
- Department of Physiology, Yeditepe University School of Medicine, İstanbul, Turkey
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Fernandez MA, Panahi S, Daniel N, Tremblay A, Marette A. Yogurt and Cardiometabolic Diseases: A Critical Review of Potential Mechanisms. Adv Nutr 2017; 8:812-829. [PMID: 29141967 PMCID: PMC5682997 DOI: 10.3945/an.116.013946] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Associations between yogurt intake and risk of diet-related cardiometabolic diseases (CMDs) have been the subject of recent research in epidemiologic nutrition. A healthy dietary pattern has been identified as a pillar for the prevention of weight gain and CMDs. Epidemiologic studies suggest that yogurt consumption is linked to healthy dietary patterns, lifestyles, and reduced risk of CMDs, particularly type 2 diabetes. However, to our knowledge, few to no randomized controlled trials have investigated yogurt intake in relation to cardiometabolic clinical outcomes. Furthermore, there has been little attempt to clarify the mechanisms that underlie the potential beneficial effects of yogurt consumption on CMDs. Yogurt is a nutrient-dense dairy food and has been suggested to reduce weight gain and prevent CMDs by contributing to intakes of protein, calcium, bioactive lipids, and several other micronutrients. In addition, fermentation with bacterial strains generates bioactive peptides, resulting in a potentially greater beneficial effect of yogurt on metabolic health than nonfermented dairy products such as milk. To date, there is little concrete evidence that the mechanisms proposed in observational studies to explain positive results of yogurt on CMDs or parameters are valid. Many proposed mechanisms are based on assumptions that commercial yogurts contain strain-specific probiotics, that viable yogurt cultures are present in adequate quantities, and that yogurt provides a minimum threshold dose of nutrients or bioactive components capable of exerting a physiologic effect. Therefore, the primary objective of this review is to investigate the plausibility of potential mechanisms commonly cited in the literature in order to shed light on the inverse associations reported between yogurt intake and various cardiometabolic health parameters that are related to its nutrient profile, bacterial constituents, and food matrix. This article reviews current gaps and challenges in identifying such mechanisms and provides a perspective on the research agenda to validate the proposed role of yogurt in protecting against CMDs.
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Affiliation(s)
- Melissa Anne Fernandez
- Heart and Lung Institute of Quebec, Laval University, Quebec, Canada
- Institute of Nutrition and Functional Foods, Laval University, Quebec, Canada
- School of Nutrition, Faculty of Agriculture and Food Sciences, Laval University, Quebec, Canada
| | - Shirin Panahi
- Department of Kinesiology, Laval University, Quebec, Canada
| | - Noémie Daniel
- Heart and Lung Institute of Quebec, Laval University, Quebec, Canada
- Institute of Nutrition and Functional Foods, Laval University, Quebec, Canada
- School of Nutrition, Faculty of Agriculture and Food Sciences, Laval University, Quebec, Canada
| | - Angelo Tremblay
- Heart and Lung Institute of Quebec, Laval University, Quebec, Canada
- School of Nutrition, Faculty of Agriculture and Food Sciences, Laval University, Quebec, Canada
- Department of Kinesiology, Laval University, Quebec, Canada
| | - André Marette
- Heart and Lung Institute of Quebec, Laval University, Quebec, Canada
- Institute of Nutrition and Functional Foods, Laval University, Quebec, Canada
- Department of Medicine, Faculty of Medicine, Laval University, Quebec, Canada
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Abstract
There has been increasing evidence that vitamin D may have a role in modifying risk of diabetes. Vitamin D has both direct and indirect effects on various mechanisms related to the pathophysiology of type 2 diabetes, including pancreatic beta cell dysfunction, impaired insulin action and systemic inflammation. This article describes the biologic plausibility behind the potential association between vitamin D and type 2 diabetes and summarizes the current evidence from human studies that suggests but does not prove a relation between vitamin D and type 2 diabetes, and briefly reports on the potential association between vitamin D and type 1 diabetes.
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Affiliation(s)
- Joanna Mitri
- Division of Endocrinology, Diabetes and Metabolism, Prima CARE Medical Center, 277 Pleasant Street, Fall River, MA 02721, USA.
| | - Anastassios G Pittas
- Division of Endocrinology, Diabetes and Metabolism, Tufts Medical Center, 800 Washington Street, Boston, MA 02111, USA
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Al-Daghri NM, Al-Attas O, Alokail MS, Alkharfy KM, Draz HM, Agliardi C, Mohammed AK, Guerini FR, Clerici M. Vitamin D Receptor Gene Polymorphisms and HLA DRB1*04 Cosegregation in Saudi Type 2 Diabetes Patients. THE JOURNAL OF IMMUNOLOGY 2012; 188:1325-32. [DOI: 10.4049/jimmunol.1101954] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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13
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Ranjzad F, Mahmoudi T, Irani Shemirani A, Mahban A, Nikzamir A, Vahedi M, Ashrafi M, Gourabi H. A common variant in the adiponectin gene and polycystic ovary syndrome risk. Mol Biol Rep 2011; 39:2313-9. [PMID: 21637951 DOI: 10.1007/s11033-011-0981-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 05/26/2011] [Indexed: 01/15/2023]
Abstract
In this study, we explored whether polymorphisms in insulin receptor (INSR), adiponectin (ADIPOQ), parathyroid hormone (PTH), and vitamin D receptor (VDR) genes are associated with polycystic ovary syndrome (PCOS). A total of 362 subjects, including 181 women with PCOS and 181 controls were enrolled in this case-control study. Two SNPs (rs2059806 and rs1799817) in the INSR gene, two SNPs (rs2241766 and rs1501299) in the ADIPOQ gene, one SNP (rs6256) in the PTH gene, and one SNP (rs757343) in the VDR gene were analyzed using PCR-RFLP method. We observed no significant difference in genotype and allele frequencies between the women with PCOS and controls for the rs2059806, rs1799817, rs1501299, rs6256, and rs757343 polymorphisms either before or after adjustment for confounding factors including age and BMI. However, the ADIPOQ rs2241766 "TT" genotype compared with "TG and GG" genotypes was associated with a 1.93-fold increased risk for PCOS (P = 0.006, OR = 1.93, 95% CI = 1.20-3.11), and the differences remained significant after adjustment for age and BMI (P = 0.039, OR = 1.72, 95% CI = 1.03-2.86). Furthermore, the ADIPOQ rs2241766 "T" allele was significantly overrepresented in women with PCOS than controls (P = 0.006; OR = 1.80, 95% CI = 1.18-2.70), and the difference remained significant after Bonferroni correction. Our findings suggest that the ADIPOQ rs2241766 "TT" genotype is a marker of increased PCOS susceptibility. This study also indicates for the first time that there are no significant association between INSR rs2059806, PTH rs6256, and VDR rs757343 gene polymorphisms and PCOS risk. However, these data remain to be confirmed in larger studies and in other populations.
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Affiliation(s)
- Fariba Ranjzad
- Research Center for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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14
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Ranjzad F, Mahban A, Shemirani AI, Mahmoudi T, Vahedi M, Nikzamir A, Zali MR. Influence of gene variants related to calcium homeostasis on biochemical parameters of women with polycystic ovary syndrome. J Assist Reprod Genet 2010; 28:225-32. [PMID: 21082232 DOI: 10.1007/s10815-010-9506-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 10/29/2010] [Indexed: 12/20/2022] Open
Abstract
PURPOSE The purpose of this study was to evaluate the associations between polymorphisms in vitamin D receptor (VDR), parathyroid hormone (PTH), calcium sensing receptor (CASR), insulin receptor (INSR), and adiponectin (ADIPOQ) genes and biochemical characteristics of women with polycystic ovary syndrome (PCOS). METHODS Serum levels of LH, FSH, estradiol, testosterone, prolactin, SHBG, glucose, IGF-1, IGFBP-1, calcium, phosphorus, PTH, 25(OH)D, and 1,25(OH)(2) D were measured in 56 women with PCOS. Furthermore, genotyping five, one, one, two, and two polymorphisms of the VDR, PTH, CASR, INSR, and ADIPOQ genes, respectively, were performed. RESULTS The VDR TaqI "CC" genotype was associated with elevated serum levels of LH (p = 0.011). There were significant associations between decreased levels of SHBG and both VDR BsmI "GG" (p = 0.009) and ADIPOQ BsmI "CC" (p = 0.016) genotypes. Furthermore, patients with CaSR Hin1I "TG" genotype showed higher HoMA-IR (p = 0.008). All these associations remained significant after Bonferroni correction. In addition, phosphorus correlated negatively with estradiol (r = -0.298, P = 0.026) and positively with glucose (r = 0.287, P = 0.032). CONCLUSIONS These data indicated for the first time that it is possible that the VDR and CASR gene variants through their effects on LH and SHBG levels, and insulin resistance are involved in pathogenesis of PCOS.
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Affiliation(s)
- Fariba Ranjzad
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, 1417613151, Tehran, Iran
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15
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Mahmoudi T, Gourabi H, Ashrafi M, Yazdi RS, Ezabadi Z. Calciotropic hormones, insulin resistance, and the polycystic ovary syndrome. Fertil Steril 2010; 93:1208-14. [DOI: 10.1016/j.fertnstert.2008.11.031] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2008] [Revised: 11/24/2008] [Accepted: 11/26/2008] [Indexed: 10/21/2022]
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Pittas AG, Lau J, Hu FB, Dawson-Hughes B. The role of vitamin D and calcium in type 2 diabetes. A systematic review and meta-analysis. J Clin Endocrinol Metab 2007; 92:2017-29. [PMID: 17389701 PMCID: PMC2085234 DOI: 10.1210/jc.2007-0298] [Citation(s) in RCA: 1273] [Impact Index Per Article: 74.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
CONTEXT Altered vitamin D and calcium homeostasis may play a role in the development of type 2 diabetes mellitus (type 2 DM). EVIDENCE ACQUISITION AND ANALYSES: MEDLINE review was conducted through January 2007 for observational studies and clinical trials in adults with outcomes related to glucose homeostasis. When data were available to combine, meta-analyses were performed, and summary odds ratios (OR) are presented. EVIDENCE SYNTHESIS Observational studies show a relatively consistent association between low vitamin D status, calcium or dairy intake, and prevalent type 2 DM or metabolic syndrome [OR (95% confidence interval): type 2 DM prevalence, 0.36 (0.16-0.80) among nonblacks for highest vs. lowest 25-hydroxyvitamin D; metabolic syndrome prevalence, 0.71 (0.57-0.89) for highest vs. lowest dairy intake]. There are also inverse associations with incident type 2 DM or metabolic syndrome [OR (95% confidence interval): type 2 DM incidence, 0.82 (0.72-0.93) for highest vs. lowest combined vitamin D and calcium intake; 0.86 (0.79-0.93) for highest vs. lowest dairy intake]. Evidence from trials with vitamin D and/or calcium supplementation suggests that combined vitamin D and calcium supplementation may have a role in the prevention of type 2 DM only in populations at high risk (i.e. glucose intolerance). The available evidence is limited because most observational studies are cross-sectional and did not adjust for important confounders, whereas intervention studies were short in duration, included few subjects, used a variety of formulations of vitamin D and calcium, or did post hoc analyses. CONCLUSIONS Vitamin D and calcium insufficiency may negatively influence glycemia, whereas combined supplementation with both nutrients may be beneficial in optimizing glucose metabolism.
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Affiliation(s)
- Anastassios G Pittas
- Division of Endocrinology, Diabetes and Metabolism, Tufts-New England Medical Center, Boston, MA 02111, USA.
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17
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Abstract
We have studied the effects of vitamin D deficiency on pancreatic A- and B-cell function. Four subjects with vitamin D deficiency and 10 healthy subjects were studied. Pancreatic B-cell function was assessed by the insulin response to an oral glucose tolerance test. An insulin tolerance test was used to evaluate pancreatic A-cell function. The patients were then treated with 2000 U/day of vitamin D3 for 6 months, after which the clinical, metabolic, biochemical and radiological features of vitamin D deficiency resolved, and pancreatic A-and B-cell function was repeated. In the vitamin D-deficient subjects pre-treatment and post-treatment serum calcium levels (mean +/- SEM) were 2.22 +/- 0.01 mmol/l and 2.24 +/- 0.01 mmol/l respectively, and 2.27 +/- 0.02 mmol/l in healthy subjects (NS). The pre-treatment level of 1,25-dihydroxy vitamin D (1,25-(OH)2D) of 29.7 +/- 3.3 pg/ml in the vitamin D deficient subjects rose to 70.3 +/- 10.3 pg/ml after treatment (p less than 0.05). The 1,25-(OH)2D level in the healthy subjects was 50.0 +/- 13.7 pg/ml (p less than 0.05 versus pre- and post-treatment values in the patients). Insulin secretion, calculated by the area under the insulin curve, was significantly lower before vitamin D3 treatment in the patients (9.09 +/- 0.7 mU X min, p less than 0.05) compared with the healthy subjects (11.9 +/- 0.5 mU X min) and post-treatment values of the patients with vitamin D deficiency (13.7 +/- 0.5 mU X min). Similar changes were seen in the insulogenic indices (delta I/delta G).(ABSTRACT TRUNCATED AT 250 WORDS)
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Wassner SJ, Li JB, Sperduto A, Norman ME. Vitamin D Deficiency, hypocalcemia, and increased skeletal muscle degradation in rats. J Clin Invest 1983; 72:102-12. [PMID: 6308041 PMCID: PMC1129165 DOI: 10.1172/jci110947] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The myopathy associated with vitamin D deficiency was examined in vitamin D-deficient and vitamin D-supplemented rats. When compared with either vitamin D-supplemented ad lib. or pair-fed rats, weight gain and muscle mass were decreased in vitamin D-deficient hypocalcemic animals. With the exception of a modest decrease in muscle creatine phosphate levels, muscle composition was unchanged by vitamin D deficiency. Muscle protein turnover rates were determined in both in vivo and in vitro studies and demonstrated that myofibrillar protein degradation was increased in vitamin D deficiency. Normal growth rates could be maintained be feeding the rats vitamin D-deficient diets containing 1.6% calcium, which maintained plasma calcium within the normal range. In addition to its role in maintaining plasma calcium, vitamin D-supplemented rats had significantly higher levels of the anabolic hormone insulin. Vitamin D supplementation may affect muscle protein turnover by preventing hypocalcemia, as well as directly stimulating insulin secretion, rather than by a direct effect within skeletal muscle.
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20
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Abstract
Endocrine abnormalities in 73 patients with primary hyperparathyroidism were studied: 8 patients were diabetic, 3 were thyrotoxic, 2 were hypothyroid, and one had a gastrinoma and carcinoid tumour. In 9 of these patients, carbohydrate metabolism and thyroid function were studied in detail pre- and 3 months postoperatively. In 6 patients following a glucose load, insulin concentrations were markedly elevated pre-operatively when compared with those found postoperatively. Likewise, in 7 patients, serum thyroxine was greater pre- than postoperatively. The aetiology of these changes and their relevance to the management of patients with primary hyperparathyroidism is discussed.
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Jenkins CR, Marlin GE. The metabolic actions of intravenous salbutamol and aminophylline singly and in combination. Br J Clin Pharmacol 1981; 11:197-201. [PMID: 7011349 PMCID: PMC1401566 DOI: 10.1111/j.1365-2125.1981.tb01124.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
1 The following four treatments were administered by constant intravenous infusion of four healthy volunteers in a balanced randomized study: 1) saline (30 min), salbutamol (0.15 micrograms kg-1 min-1 for 30 min) (sS), 2) saline, aminophylline (0.2 mg kg-1 min-1 for 30 min) (sA), 3) salbutamol, salbutamol (SS) and 4) aminophylline, salbutamol (AS). 2 Heart rate was recorded and venous blood taken for estimation of insulin, glucose, potassium and theophylline before and during the infusions (10, 20, 30, 40, 50 and 60 min). 3 The mean, peak heart rate increases from control, baseline values were 23.0 (sS), 3.5 (sA), 28.5 (SS) and 28.0 (AS) beats/min, the mean, peak insulin increases, 34.0 (sS), 0.5 (sA), 39.0 (SS) and 57.5 (AS) microU ml-1, the mean, peak glucose increases, 1.4 (sS), 0.1 (sA), 2.6 (SS) and 2.0 (AS) mmol 1(-1) and the mean, peak potassium changes, -0.45 (sS), 0.58 (sA), -0.78 (SS) and -0.68 (AS) mmol 1(-1). 4 The mean, peak serum theophylline levels were 48.1 mumol 1(-1) at 60 min in sA and 52.6 mumol 1(-1) at 50 min in AS (39.1 mumol 1(-1) at 30 min). 5 Salbutamol stimulated significant insulin release and produced hypokalaemia and glycogenolysis, whereas aminophylline induced no metabolic effect. 6 A comparison of sS and AS indicated a trend for aminophylline to potentiate the metabolic effects of salbutamol.
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Siegel EG, Wollheim CB, Kikuchi M, Renold AE, Sharp GW. Dependency of cyclic AMP-induced insulin release on intra- and extracellular calcium in rat islets of Langerhans. J Clin Invest 1980; 65:233-41. [PMID: 6153182 PMCID: PMC371360 DOI: 10.1172/jci109665] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Calcium and cyclic AMP are important in the stimulation of insulin release. The phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) raises islet cAMP levels and causes insulin release at nonstimulatory glucose concentrations. In isolated rat pancreatic islets maintained for 2 d in tissue culture, the effects of IBMX on insulin release and 45Ca++ fluxes were compared with those of glucose. During perifusion at 1 mM Ca++, 16.7 mM glucose elicited a biphasic insulin release, whereas 1 mM IBMX in the presence of 2.8 mM glucose caused a monophasic release. Decreasing extracellular Ca++ a monophasic release. Decreasing extracellular Ca++ to 0.1 mM during stimulation reduced the glucose effect by 80% but did not alter IBMX-induced release. Both glucose and IBMX stimulated 45Ca++ uptake (5 min). 45Ca++ efflux from islets loaded to isotopic equilibrium (46 h) was increased by both substances. IBMX stimulation of insulin release, of 45Ca++ uptake, and of efflux were not inhibited by blockade of Ca++ uptake with verapamil, whereas glucose-induced changes are known to be inhibited. Because IBMX-induced insulin release remained unaltered at 0.1 mM calcium, it appears that cAMP-stimulated insulin release is controlled by intracellular calcium. This is supported by perifusion experiments at 0 Ca++ when IBMX stimulated net Ca++ efflux. In addition, glucose-stimulated insulin release was potentiated by IBMX. These results suggest that cAMP induced insulin release is mediated by increases in cytosolic Ca++ and that cAMP causes dislocation of Ca++ from intracellular stores.
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