Sex Hormone-binding Globulin In Subjects Research Articles

The association between sex hormone-binding globulin and type 2 diabetes in Nigerian men.

BackgroundEpidemiological studies have shown that sex hormone-binding globulin (SHBG) has a role in glucose homeostasis in both men and women. However, a prospective study on Japanese-American subjects concluded that SHBG was not a significant risk factor in either men or women, suggesting ethnic differences. We were not aware of any evaluation of SHBG in subjects of African ancestry.ObjectivesWe investigated the association between SHBG and insulin resistance in type 2 diabetic diabetic men in a hospital in Nigeria.MethodForty-eight male subjects with type 2 diabetes and 20 non-diabetic male subjects were recruited in this cross-sectional hospital-based study by the convenient sampling method. Height and circumferences around the waist and hip were measured to the nearest 0.5 cm and the waist–hip ratio was calculated from this measurement. Weight was measured and body mass index was calculated. Fasting plasma glucose concentration was measured by the glucose oxidase method with a between-run coefficient of variation of 3%. Insulin and SHBG were measured by means of enzyme-linked immunosorbent assay (ELISA).ResultsThere was a statistically-significant difference between test results for the diabetic and non-diabetic patients. The mean SHBG concentration was higher in the non-diabetic group (42.2 nmol/L) than the diabetic group (30.5 nmol/L). A significant inverse association between insulin resistance and SHBG was observed (r = 0.353, p < 0.015).ConclusionThis study supported earlier observations that a significant inverse correlation exists between SHBG and insulin resistance and provides evidence that the relationship may extend to type 2 diabetic men of African ancestry in Nigeria.

Dietary Isoflavones Affect Sex Hormone-Binding Globulin Levels in Postmenopausal Women1

The studies presented in this report were designed to further investigate the causal association between phytoestrogen action and increase in sex hormone-binding globulin (SHBG) levels. Phytoestrogens include isoflavones that bind to estrogen receptors and therefore exert estrogenic action. This study included 20 postmenopausal women that ingested 30 g soy milk daily for 10 weeks. Plasma concentrations of isoflavones and SHBG were measured. Total isoflavones significantly increased from 0.014 +/- 0.01 micromol/L (baseline) to 0.53 +/- 0.19 ,micromol/L, and paired responses showed that some subjects clearly increased their SHBG levels. The percent change in SHBG showed a positive correlation with phytoestrogen concentration; all women who had circulating phytoestrogen levels above 0.6 micromol/L increased by at least 30% their SHBG values. Results suggest that phytoestrogens may significantly increase SHBG in subjects whose SHBG concentrations are in the low end of the concentration range.