Biology of Reproduction, Vol 27, 183-188, Copyright © 1982 by Society for the Study of Reproduction

ARTICLES

Hypophysectomized male rats treated with polydimethylsiloxane capsules containing testosterone: effects on spermatogenesis, fertility, and reproductive tract concentrations of androgens

AE Buhl, JC Cornette, KT Kirton and YD Yuan

Spermatogenesis, reproductive luminal contents and androgen concentrations were examined in hypophysectomized male rats treated with 1 of 3 testosterone (T) dosages for 60-64 days and in sham- operated controls. Hypophysectomized rats treated with 2 cm long T implants showed normal mating but reduced fertility, while normal fertility was maintained in animals given 8 or 3 x 8 cm T. Spermatogenesis in the hypophysectomized groups treated with 2 cm T for 10 days was generally arrested at the spermatocyte stage, while in the hypophysectomized animals treated with 2 cm T for 64 days spermatogenesis was halted at the spermatid stage. The 8 and 3 x 8 T- treated hypophysectomized animals had normal spermatogenesis with only minimal focal areas of degenerating seminiferous epithelium. Serum T concentrations were reduced by hypophysectomy, maintained at control levels by the 2 cm T dosage and increased to pharmacological levels in a dose-dependent manner by 8 and 3 x 8 cm T treatments. Testicular T concentrations also responded in a dose-dependent manner but the 3 x 8 cm T dose was not sufficient to keep testicular T at control levels. Dihydrotestosterone (DHT) in the caput epididymidis was maintained at control levels by the 8, reduced by the 2 and elevated by the 3 x 8 cm T treatment. Without gonadotropins, higher than normal levels of serum T are required to maintain normal fertility, although this normal reproductive capacity is possible even with greatly reduced testicular T concentrations.