Gonadal Dysfunction in the Spontaneously Diabetic BB Rat: Alterations of Testes Morphology, Serum Testosterone and LH

Summary

Serum testosterone, luteinizing hormone (LH), testicular histology and ultrastructure were examined in 91 spontaneously diabetic BB, semi-starved, and control Wistar rats. Between 80-120 days of age serum testosterone was decreased (1.67±.25 vs. 2.95±.48 ng/ml; P < .05) in the BB rats compared to controls but not different from semi-starved rats. LH values were similar in control and BB rats (49.4±10.9 vs. 46.8±6.2 ng/ml). Abnormal lipid droplets were noted within Leydig cells at this period. From 121-150 days of age serum testosterone was lower in BB (1.38±.23 vs. 3.42±.45 vs. 2.94±.81 ng/ml; P < .05) than controls or semi-starved rats. Serum LH was not significantly higher in controls than in BB rats (63.2±7.4 vs. 36.6±12 ng/ml; P = NS). Between 151-200 days of age, there was further lipid accumulation in Leydig cells in the BB rat and occasional epithelial disorganization. After 200 days, serum testosterone decreased (P < .05) to similar levels in both control and BB rats (1.42±.87 vs. 1.22±.25; P = NS) and was similar in BB rats after 250 days (1.02±.2 ng/ml). After 250 days of age Leydig cell morphology appeared relatively normal but marked alterations were apparent in Sertoli cells, germ cells and morphology of the tubule wall. A group of rats designated “retired breeders” age 202±10 days, had significantly (P < .01) lower prostate and testes weights although serum testosterone (2.61±.57 vs. 4.24±.54 ng/ml; P = NS) and LH values (67.1±22 vs. 57.7±10 ng/ml; P = NS) were not different. We suggest that gonadal dysfunction in these animals before 250 days is related to low testosterone levels and not due to altered spermatogenesis. However, after 250 days germ cell depletion and epithelial dissolution may explain decreased gonadal dysfunction in these older animals.

Key-Words:

Testosterone - Testis - LH - Diabetes