DECREASED ANDROGEN PRODUCTION IN THE TESTES OF THYROIDECTOMIZED RATS

The testicular androgen production of thyroidectomized (Tx) rats in response to human chorionic gonadotropin (hCG) stimulation was studied in vitro with decapsulated testes and dispersed testicular interstitial cells. The effects of the thyroidectomy were more severe in immature rats than in adult rats resulting in a greater decrease in overall body weight, weight of testes, adrenal glands, ventral prostate glands and seminal vesicles, and changes in serum levels of thyrotropin (TSH) and androgen in the younger animals. Decreased androgen secretion from hCG stimulation by the testes was noted in both immature and adult Tx rats. The androgen production, on the basis of an equal number of testicular interstitial cells, in the adult Tx rats were less sensitive to hCG stimulation than the euthyroid controls. The cellular androgen production was dependent on the cell concentration and incubation time. Under various incubation conditions, the Tx group always showed less androgen production as compared to the euthyroid control. The results of this study imply that decreased cellular androgen production in hypothyroid rats may lead to decreased serum androgen levels.