Maintenance of spermatogenesis and seminal vesicles in the hypophysectomized catfish, Heteropneustes fossilis (Bloch): effects of ovine and salmon gonadotropin, and testosterone
The effects of 20-day treatment with ovine luteinizing (LH) and follicle-stimulating hormone (FSH), partially purified salmon gonadotropin (SG-G100) and testosterone were investigated by evaluating the maintenance of spermatogenesis in the testes and secretory activity in the seminal vesicles of the catfish after hypophysectomy during the prespawning period. Low doses of LH (0.1 or 1 .mu.g per fish) neither maintained spermatogenesis in the testes nor secretory activity in the seminal vesicles; a higher dose of LH (10 .mu.g per fish) maintained spermatogenesis qualitatively, and sustained the seminal vesicles in a moderately secretory state. One microgram of SG-G100 per fish partially maintained spermatogenesis but the seminal vesicles showed poor maintenance. Ten micrograms of SG-G100 per fish sustained spermatogenesis qualitatively and quantitatively, and induced spermiation; the seminal vesicles, though enlarged, contained little secretion, indicating possible reduction through spermiation. FSH did not maintain spermatogenesis in the testes or secretory activity in the seminal vesicles. Testosterone (10, 100, or 500 .mu.g per fish) had a dose-dependent maintenance response in the testes and seminal vesicles; with 500 .mu.g of testosterone the maintenance of testes and seminal vesicles was similar to that in initial intact controls, with no indication of spermiation.