Postnatal development of hepatic UDP-glucuronosyltransferase and sulphotransferase activities towards androsterone and 4-nitrophenol as well as cytochrome P-450 contents was studied in male and female Wistar rats. The rats with high and low UDP-glucuronosyltransferase activity towards androsterone were classified by the genotype of the parent animals. UDP-glucuronosyltransferase activity towards androsterone began rapidly to enhance after 30 days of age in the high-activity group, whereas the transferase activity remained low throughout in the low-activity group. Such a striking difference was not observed in UDP-glucuronosyltransferase activity towards 4-nitrophenol, sulphotransferase activity towards androsterone and 4-nitrophenol, and cytochrome P-450 contents. Sex-based difference in the sulphotransferase activity was marked after 30 days of age. Sulphotransferase activity towards androsterone was much higher in adult females than in adult males, whereas higher sulphation activity towards 4-nitrophenol was found in adult males. The results also indicate that the low level of the UDP-glucuronosyltransferase activity did not lead to compensatory stimulation of the sulphotransferase activity.
