Some Effects of Experimentally-Induced Diabetes on Pituitary-Testicular Relationships in Rats[*]

Abstract

The effect of experimentally-induced diabetes mellitus on reproductive organ weights, serum and pituitary gonadotropin levels and serum testosterone levels was studied in 3-month old rats. In experiment 1, intact rats were treated with alloxan monohydrate or streptozotocin. In experiments 2 and 3, intact and castrated rats were rendered diabetic with alloxan (experiment 2) or streptozotocin (experiment 3). The duration of each experiment was 3 weeks.

In each experiment diabetes resulted in body weight losses or reduced body weight gain, elevated serum glucose concentrations and reduced assessory sex gland weights (intact rats). Serum levels of testosterone were depressed (P < 0.05 or P < 0.01) in diabetic rats. Serum levels of LH were significantly (P < 0.05) lower in intact diabetics than in controls when pooled data from the three experiments were compared. Serum levels of FSH were not affected by diabetes. Pituitary concentrations of FSH were elevated (P < 0.05) in diabetics in two of the three experiments, while LH concentrations were elevated (P < 0.05 or P < 0.01) in diabetics in all experiments. The hypersecretion of gonadotropins in castrated rats was not affected by diabetes.

Key words

Alloxan - Streptozotocin - Follicle Stimulating Hormone - Testosterone - Castration - Diabetes Mellitus - Pituitary

1 This study was supported by grants (MA-4454 and MA-3627) from the Medical Research Council of Canada.

1 This study was supported by grants (MA-4454 and MA-3627) from the Medical Research Council of Canada.