Effects of methyl testosterone on the testis and secondary sex characters of the hypophysectomized adult guppy Poecilia reticulata Peters

Abstract

Exogenous methyl testosterone appears to have a direct spermatokinetic effect on the testis of the hypophysectomized adult guppy. The gonosomatic index is significantly increased; spermatogonial cysts divide rapidly and transform into spermatocytes, but later stages of spermatogenesis do not appear. The regressed epithelial cells lining the sperm ducts, the Sertoli cells, and the interstitial cells resume their normal appearance. The gonopodium remains unaffected, but there is moderate recovery in the content of integumentary lipophores.