Concept: Sex hormone-binding globulin
Sleep restriction is associated with development of metabolic ill-health, and hormonal mechanisms may underlie these effects. The aim of this study was to determine the impact of short term sleep restriction on male health, particularly glucose metabolism, by examining adrenocorticotropic hormone (ACTH), cortisol, glucose, insulin, triglycerides, leptin, testosterone, and sex hormone binding globulin (SHBG).
Alcohol (ethanol) and resistance exercise can independently affect circulating bioavailable testosterone concentration. PURPOSE: The purpose of this study was to examine the testosterone bioavailability and the anabolic endocrine milieu in response to acute ethanol ingestion following a bout of heavy resistance exercise. METHODS: Eight resistance trained men (mean ± SD: 25.3 ± 3.2 yrs, 87.7 ± 15.1 kg, 177 ± 7 cm) completed two identical acute heavy resistance exercise tests (AHRET: six sets of 10 repetitions of Smith machine squats) separated by 1 week. Post-AHRET participants consumed either 1.086 g of grain ethanol per kg lean mass (EtOH condition) or no ethanol (Placebo condition). Blood samples were collected immediately before exercise (PRE), immediately after exercise (IP), and every 20 min postexercise for 300 min. Samples following IP were pooled into phases (20-40 min, 60-120 min, and 140-300 min after exercise) and analyzed for total (TT) and free testosterone (FT), sex hormone binding globulin (SHBG), cortisol, and estradiol. RESULTS: Peak blood ethanol concentration (0.088 ± 0.015 g·dl) was achieved 60-90 min post-exercise. TT and FT was elevated significantly (p≤0.05) at IP for both conditions. At 140-300 min post-exercise TT, FT, and free androgen index were significantly higher for EtOH (TT: 22.5 ± 12.5 nmol·l ; FT: 40.5 ± 7.6 pmol·l) than for Placebo (TT: 13.9 ± 6.8 nmol·l; FT: 22.7 ± 10.0 pmol·l). No differences between conditions were noted for SHBG, Cortisol, or Estradiol. CONCLUSION: Post-exercise ethanol ingestion affects the hormonal milieu including testosterone concentration and bioavailability during recovery from resistance exercise.
BACKGROUND: Findings from observational studies suggest that sex hormone-binding globulin (SHBG) and endogenous sex hormones may be mediators of the putative relation between coffee consumption and lower risk of type 2 diabetes. The objective of this study was to evaluate the effects of caffeinated and decaffeinated coffee on SHBG and sex hormone levels. FINDINGS: After a two-week run-in phase with caffeine abstention, we conducted an 8-week parallel-arm randomized controlled trial. Healthy adults (n = 42) were recruited from the Boston community who were regular coffee consumers, nonsmokers, and overweight. Participants were randomized to five 6-ounce cups of caffeinated or decaffeinated instant coffee or water (control group) per day consumed with each meal, mid-morning, and mid-afternoon. The main outcome measures were SHBG and sex hormones [i.e., testosterone, estradiol, dehydroepiandrosterone sulfate].No significant differences were found between treatment groups for any of the studied outcomes at week 8. At 4 weeks, decaffeinated coffee was associated with a borderline significant increase in SHBG in women, but not in men. At week 4, we also observed several differences in hormone concentrations between the treatment groups. Among men, consumption of caffeinated coffee increased total testosterone and decreased total and free estradiol. Among women, decaffeinated coffee decreased total and free testosterone and caffeinated coffee decreased total testosterone. CONCLUSIONS: Our data do not indicate a consistent effect of caffeinated coffee consumption on SHBG in men or women, however results should be interpreted with caution given the small sample size. This is the first randomized trial investigating the effects of caffeinated and decaffeinated coffee on SHBG and sex hormones and our findings necessitate further examination in a larger intervention trial.
Polycystic ovary syndrome (PCOS) is the most common reproductive disorder in women, yet there is little consensus regarding its aetiology. Here we perform a genome-wide association study of PCOS in up to 5,184 self-reported cases of White European ancestry and 82,759 controls, with follow-up in a further ∼2,000 clinically validated cases and ∼100,000 controls. We identify six signals for PCOS at genome-wide statistical significance (P<5 × 10(-8)), in/near genes ERBB4/HER4, YAP1, THADA, FSHB, RAD50 and KRR1. Variants in/near three of the four epidermal growth factor receptor genes (ERBB2/HER2, ERBB3/HER3 and ERBB4/HER4) are associated with PCOS at or near genome-wide significance. Mendelian randomization analyses indicate causal roles in PCOS aetiology for higher BMI (P=2.5 × 10(-9)), higher insulin resistance (P=6 × 10(-4)) and lower serum sex hormone binding globulin concentrations (P=5 × 10(-4)). Furthermore, genetic susceptibility to later menopause is associated with higher PCOS risk (P=1.6 × 10(-8)) and PCOS-susceptibility alleles are associated with higher serum anti-Müllerian hormone concentrations in girls (P=8.9 × 10(-5)). This large-scale study implicates an aetiological role of the epidermal growth factor receptors, infers causal mechanisms relevant to clinical management and prevention, and suggests balancing selection mechanisms involved in PCOS risk.
As the impact of high intensity interval training (HIIT) on systemic hormones in aging men is unstudied to date, we investigated whether total testosterone (TT), sex hormone binding globulin (SHBG), free testosterone (free-T), and cortisol (all in serum) were altered following HIIT in a cohort of 22 lifelong sedentary (62 ± 2 years) older men. As HIIT requires preconditioning exercise in sedentary cohorts, participants were tested at three phases, each separated by six weeks' training; baseline (phase A), following conditioning exercise (phase B), and post-HIIT (phase C). Each measurement phase used identical methods. TT was significantly increased following HIIT (~17%; P<0.001) with most increase occurring during preconditioning (~10%; P=0.007). Free-T was unaffected by conditioning exercise (P=0.102) but was significantly higher following HIIT compared to baseline (~4.5%; P=0.023). Cortisol remained unchanged from A to C (P=0.138). The present data indicate a combination of preconditioning and HIIT increases TT and SHBG in sedentary older males, with the HIIT stimulus accounting for a small but statistically significant increase in free-T. Further study is required to determine the biological importance of small improvements in free-T in aging men.
- The Journal of clinical endocrinology and metabolism
- Published over 4 years ago
ContextThere are few population-based studies reporting longitudinal changes in total testosterone (T), luteinizing hormone (LH), follicle stimulating hormone (FSH), and sex hormone binding globulin (SHBG) levels, and limited information on risk factors for their change.ObjectiveThe objective of the study was to examined 5-year changes in serum T, LH, FSH, and SHBG levels among Australian men.DesignA randomly selected, community based cohort of 1,588 men age 35 or older at recruitment (mean age 54±11y), with available data at two visits. Men on medications known to affect, or with established pathology of, the hypothalamo-pituitary gonadal axis were excluded, leaving 1,382 for analysis.ResultsMean baseline and follow-up T levels were 16.2±1.4nmol/L and 15.6±1.4nmol/L; a change of -0.13nmol/L/y. Annualized T changes were associated with being unmarried, obesity, and smoking at baseline, but not diabetes, hypertension, or cardiovascular disease. T declined in men with persistent depression, or who developed chronic disease, and increased in men who were married, as compared to unmarried, at both time points. In the multivariate analysis, smoking cessation, development of central (waist ≥100cm) or generalised (BMI ≥ 30) obesity resulted in T decreases of 0.36, 0.25, and 0.20nmol/L/y respectively. Quitting smoking, developing obesity, and having persisting depression were inversely related to SHBG change.ConclusionsAn age-related decline in T levels is not inevitable but largely explained by smoking behaviour and intercurrent changes in health status, particularly obesity and depression.
OBJECTIVE: To evaluate the association between serum bisphenol-A (BPA) concentration and sex hormone levels in men. DESIGN: Cross-sectional study. SETTING: Not applicable. PATIENT(S): A total of 290 men with or without BPA exposure in the workplace. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Serum sex hormone levels. RESULT(S): After adjustment for potential confounders using linear regression, increasing serum BPA concentration was statistically significantly associated with  decreased androstenedione levels,  decreased free testosterone levels,  decreased free androgen index, and  increased sex hormone-binding globulin levels. Comparison of hormone levels between workers exposed and unexposed to BPA showed similar associations. CONCLUSION(S): Exposure to a high BPA level may impact sex hormone levels in men.
It remains unclear whether endogenous sex hormones (ESH) are associated with risk of type 2 diabetes (T2D) in women. Data of 3,117 postmenopausal women participants of the Rotterdam Study were analyzed to examine whether ESH and sex hormone-binding globulin (SHBG) were associated with the risk of incident T2D. Additionally, we performed a systematic review and meta-analysis of studies assessing the prospective association of ESH and SHBG with T2D in women. During a median follow-up of 11.1 years, we identified 384 incident cases of T2D in the Rotterdam Study. No association was observed between total testosterone (TT) or bioavailable testosterone (BT) with T2D. SHBG was inversely associated with the risk of T2D, whereas total estradiol (TE) was associated with increased risk of T2D. Similarly, in the meta-analysis of 13 population-based prospective studies involving more than 1,912 incident T2D cases, low levels of SHBG and high levels of TE were associated with increased risk of T2D, whereas no associations were found for other hormones. The association of SHBG with T2D did not change by menopause status, whereas the associations of ESH and T2D were based only in postmenopausal women. SHBG and TE are independent risk factors for the development of T2D in women.
Abstract The aim of this study was to compare metabolic parameters, body composition (BC) and muscle strength of women with and without polycystic ovary syndrome (PCOS). This was a case-control study that evaluated 40 women with PCOS and 40 controls. Androgens and insulin resistance were measured. BC was based on dual-energy X-ray absorptiometry. Isometric handgrip and maximal dynamic muscle strength (1-RM) strength tests were performed. Median total testosterone (p < 0.01), free androgen index (p < 0.01), insulin (p < 0.01) and homeostasis model assessment-insulin resistance (p = 0.02) were higher and sex hormone binding globulin (SBHG) (p = 0.04) was lower in the PCOS group. Normoweight women with PCOS had higher percentages of android body fat. However, the prevalence of android fat distribution was higher in the PCOS than in the control group (p = 0.04). The strength 1-RM in bench press (p < 0.01), muscle strength relative to lean muscle mass in the dominant lower limb (p = 0.04) and isometric handgrip strength tests (p = 0.03) was higher in the PCOS group. PCOS was a determinant of strength in the bench press exercise (p = 0.04). The hyperandrogenism was a predictor of increased strength in biceps curl exercises (p = 0.03) in the dominant lower limb (p = 0.02) and isometric handgrip strength (p = 0.03). In conclusion, women with PCOS have greater muscle strength and a higher prevalence of central obesity, but no difference in BC. Muscle strength may be related to high androgen levels in these women.
- Climacteric : the journal of the International Menopause Society
- Published over 3 years ago
ABSTRACT Objective: Lepidium meyenii (Maca), has been used for centuries for its fertility enhancing and aphrodisiac properties. In an Australian study, Maca improved anxiety and depressive scores. The effects of Maca on hormones, lipids, glucose, serum cytokines, blood pressure, menopausal symptoms and general well-being in Chinese postmenopausal women were evaluated Methods: A randomized, double-blind, placebo-controlled crossover study was conducted in 29 postmenopausal Hong Kong Chinese women. They received 3.3 g/day of Maca or placebo for 6 weeks each, in either order, over 12 weeks. At baseline, week 6 and week 12, estradiol, follicle stimulating hormone (FSH), sex hormone binding globulin (SHBG), thyroid stimulating hormone (TSH), full lipid profiles, glucose and serum cytokines, were measured. The Greene Climacteric, SF-36v2, Women’s Health Questionnaire and Utian quality of life, scales were used to assess the severity of menopausal symptoms and health related quality of life. Results: There were no differences in estradiol, FSH, TSH, SHBG, glucose, lipid profiles and serum cytokines amongst those who received Maca as compared to placebo group, however, a significant decrease in diastolic blood pressure and depression was apparent after Maca treatment. Conclusions: Maca does not exert hormonal or immune biological action in the small cohort of patients studies, however, it appears to reduce symptoms of depression and improve diastolic blood pressure in Chinese postmenopausal women. Although results are comparable to previous similar published studies in postmenopausal women, there might be a cultural difference among the Chinese postmenopausal women in terms of symptom reporting.