Effect of Endogenous Insulin Levels on Serum Testosterone, Glycemic, and Obesity Parameters in Premenopausal Women with Type 2 Diabetes Mellitus

In the present study, the relationship between different serum levels of endogenous testosterone, obesity, and metabolic markers in premenopausal type 2 diabetic women was evaluated for their role in the pathogenesis of diabetes mellitus. A randomized cross-sectional study of total of 66 premenopausal women with T2DM was allocated into three groups with high level, low level, and near-normal fasting insulin level. The control group includes 30 women with matched age and whom is diabetes. Free fasting blood glucose (FBG), postprandial blood glucose (PPG) , fasting serum insulin (FSI), glycosylated hemoglobin (HbA1c), total cholesterol, triglyceride (TG), free testosterone (FT), total testosterone (TT), C-peptide protein, and sex hormone binding globulin (SHBG) were measured. All premenopausal T2DM women tended to significant high levels of BMI, HOMA-IR, C-peptide, FBG, HbA1c and PPS compared to controls (P˂0.05) and with significant difference among groups parallel to their endogenous insulin levels. Total testosterone and free testosterone were significantly lower in all premenopausal T2DM women (P˂0.05), but SHBG showed low but non-significant difference among groups. HOMA-IR showed significant correlation with free testosterone in premenopausal T2DM women with high insulin level (P˂0.05), but no significant correlation with total testosterone and SHBG was found among all patients groups. In conclusion, premenopausal T2DM women of matched age and duration of the disease have low levels of SHBG and testosterone, which was correlated to insulin resistance in hyperinsulinemic women only.