Effect of steroidal sex hormones on the sex-related differences in the hepatic activities of gamma-glutamyltranspeptidase, glutathione S-transferase and glutathione peroxidase in rats.

The activities of gamma-glutamyltranspeptidase (gamma-GTP) and glutathione peroxidase (GSH-Px) were higher in female than in male rat liver. Glutathione S-transferase (GST) activities were conversely higher in males than females. Estradiol administration to castrated rats enhanced the gamma-GTP activity. Castration produced a significant increase in GSH-Px activities which was reduced to the control level by subsequent testosterone treatment. Ovariectomized rats had markedly increased the GST activity. These results suggest that GSH-related enzymes studied here may be subject to modulation by androgenic and estrogenic influences.