Serum testosterone and fasting serum C-peptide level in obese diabetic males and females

ABSTRACT

This study investigated the relationship between obesity, hyperinsulinemia and testosterone in obese diabetic patients. Ten obese non-insulin dependent diabetic [NIDDM] males [group A] and ten obese [NIDDM] females [group B], together with ten normally healthy male and female subjects served as controls [group C] were included in the study. Fasting serum C-peptide, total serum testosterone, sex hormone binding globulin [SHBG] were estimated by radioimmunoassay. Free androgen index [FAI] was also calculated. The results showed that body mass index [BMI] and fasting serum C- peptide were significantly higher in group A and B than in group C, in association with significant positive correlation between BMI and fasting serum C-peptic in group A and B as well as between fasting blood glucose and serum C-peptide in obese diabetic patients. Significant negative correlation was observed between BMI serum testosterone as well as between BMI and SHBG in obese diabetic patients. Moreover, a significant negative correlation was found between fasting serum C-peptide and SHBG in both groups A and B. The mean calculated free androgen index was significantly higher in obese diabetics than in control subjects. However, insignificant positive correlation was found between FAI, BMI and fasting serum C- peptide in obese diabetic males. This correlation was significant in obese diabetic females. It was concluded that SHBG estimation might be considered as a screening test of the hyperinsulinemic states, which is considered as a risk factor in developing diabetes