Responses of seminal vesicle and testicular beta-glucuronidase and beta-N-acetylglucosaminidase to testosterone and some metabolites in Heteropneustes fossilis (Bloch)

Intraperitoneal administration of testosterone for 20 days produced differe ntial effects on beta -glucuronidase and beta -N-acetylglucosaminidase (bet a -Glc) activity in seminal vesicle (SV) and testis of the catfish Heteropn eustes fossilis in preparatory phase (March). The lower dosages of 0.25 and 0.5 mug/g body weight (BW) of the steroid did not alter enzyme activity, a nd the higher dosages (1.0 and 2.0 mug/g BW) inhibited it significantly. Un der in vitro conditions, addition of ascorbate and fructose 0.5-100 mM) to the incubation medium influenced enzyme activity differentially. At concent rations 0.5 and 1.0 mM, both fructose and ascorbate were ineffective except for the inhibition of testicular beta -Glc activity in the 1.0 mM ascorbat e group. At higher concentrations (10, 50, and 100 mM), ascorbate inhibited enzyme activity in a concentration-dependent manner. At 10 mM concentratio n of fructose, only testicular beta -Glc activity was inhibited, but at hig her concentrations (50 and 100 mM), activities of both enzymes decreased un iformly in a concentration-dependent manner. The addition of glucose had no significant effect on the enzyme activity at any of the concentrations tes ted. The results suggest that the inhibitory effect of testosterone on enzy me activity may be mediated through androgen-dependent metabolites, such as fructose and ascorbate. J. Exp. Zool. 290:777-782, 2001. (C) 2001 Wiley-Li ss, Inc.