Effects of administration of cyproterone acetate on seminal vesicle and testicular activity, and serum testosterone and estradiol-17-β levels in the catfish Clarias batrachus

Abstract

Cyproterone acetate (CA) was administered in the catfish Clarias batrachus (BW 60–65 g) in a dose of 1 mg/fish daily for 21 days in the prespawning (June) phase of the reproductive cycle. The treatment caused a marked decrease in the size and weight of both testis and seminal vesicle (SV). Spermatogenesis was retarded, inhibiting the transformation of spermatids into spermatozoa. The SV was greatly regressed; the lobules were small with empty lumina or collapsed and fibrosed together with the interstitium in many areas. The CA treatment decreased significantly the concentrations of total proteins, fructose, hexosamines and sialic acid in both the SV and testis, and serum levels of testosterone and estradiol-17β. The results indicate that the regressive changes in the SV and testis were a sequel to decreased androgen level and blockade of androgen actions by interrupting, most likely, the androgen receptor mechanisms.