Hypophysectomized male rats treated with polydimethylsiloxane capsules containing testosterone: effects on spermatogenesis, fertility, and reproductive tract concentrations of androgens.
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.
D000728:Androgens / Q000032:analysis*; D000818:Animals; D003692:Delayed-Action Preparations; D004129:Dimethylpolysiloxanes / Q000494:pharmacology*; D005298:Fertility / Q000187:drug effects*; D005837:Genitalia, Male / Q000032:analysis / Q000187:drug effects*; D007016:Hypophysectomy; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012828:Silicones / Q000494:pharmacology*; D013091:Spermatogenesis / Q000187:drug effects*; D013737:Testis / Q000473:pathology; D013739:Testosterone / Q000494:pharmacology*
D000728:Androgens; D003692:Delayed-Action Preparations; D004129:Dimethylpolysiloxanes; D012828:Silicones; D013739:Testosterone