Elevated levels of sex hormones and sex hormone binding globulin in male patients with insulin dependent diabetes mellitus. Effect of improved blood glucose regulation.

In a prospective study we have measured serum levels of sex hormone-binding globulin (SHBG), androgens, oestrogens and gonadotropins in 20 male IDDM patients with the aim of evaluating the effect of improved glycaemic control on these levels and to compare the IDDM patients with an age- and weight-matched healthy non-diabetic control group. The patients were chosen from the male IDDM patients attending the outpatient clinic at the Department of Endocrinology, Odense University Hospital. Glycaemic control was optimized by a trained diabetologist according to the patients' measurements of home blood glucose concentrations and reported hypoglycaemic episodes during a three month period. Prior to regulation the patients, compared to healthy control subjects, had significantly higher serum levels of oestrone (0.29 +/- 0.02 vs 0.16 +/- 0.01 nmol/l (Mean +/- SEM), p < 0.01), 17 beta-oestradiol (0.12 +/- 0.01 vs 0.08 +/- 0.01 nmol/l, p < 0.01), dihydrotestosterone (4.20 +/- 0.18 vs 1.66 +/- 0.09 nmol/l, p < 0.01), total testosterone (20.7 +/- 0.9 vs 17.8 +/- 1.1 nmol/l, p < 0.05) and SHBG (42.3 +/- 2.9 vs 15.5 +/- 3.5 nmol/l, p < 0.05), while the calculated free-testosterone was lower (0.34 +/- 0.02 vs 0.40 +/- 0.02 nmol/l, p = 0.068). After regulation, the patients obtained significantly lower levels of glycosylated haemoglobin (10.4 +/- 0.3 vs 8.9 +/- 0.2%, p < 0.005) and serum fructosamine (1.50 +/- 0.05 vs 1.34 +/- 0.04 nmol/l, p < 0.005) on a higher 24 hour insulin dose (52.7 +/- 4.4 vs 59.2 +/- 4.6 IU/24 h, p < 0.005). Levels of free-testosterone (0.41 +/- 0.04 nmol/l), oestrone (0.33 +/- 0.03 nmol/l), oestradiol (0.14 +/- 0.01 nmol/l), delta 4-androstenedione (4.44 +/- 0.43 vs 3.85 +/- 0.42 nmol/l), and prolactin (249 +/- 24 vs 200 +/- 19 mIU/l) increased compared to values obtained before regulation (all p < 0.05). We conclude that SHBG, testosterone, dihydrotestosterone and oestrogen levels are increased in male IDDM patients. High SHBG levels tend to keep the free fractions of sex hormones within normal limits. During improvement of glycaemic control with insulin, levels of free-testosterone and its bioprecursors and metabolites rise. This may partly be due to the increased daily insulin dose and/or to the improvement in glycaemic control itself.