The influence of age and some inducers on UDP-glucuronyltransferase activity.
UDP-glucuronyltransferase (UDP-GT) activity was examined in male Wistar rats aged 0.5, 1, 2, 4, 8, 12, 20, and 28 months. The rats were treated with phenobarbital (75 mg/kg, 72 and 48 h before death), beta-naphthoflavone or dexamethasone (40 mg/kg and 20 mg/kg, respectively, for three days before death). Prior to decapitation the rats were fasted for 12 h. Hepatic microsomes were prepared according to the method of Dallner. UDP-GT activity was determined by the method of Burchell and Weatherill. p-Nitrophenol was used as an aglucone. UDP-GT activity decreased rapidly in the control rats aged from two weeks to four months. In the older control rats the activity tended to increase. Two-week-old rats treated with phenobarbital showed a slightly increased UDP-GT activity. In the older animals (up to one year) UDP-GT activity increased to 150% of the control value and stayed at this level in the remaining age groups. beta-Naphthoflavone was a more potent inducer of UDP-GT than phenobarbital. The activity of beta-naphthoflavone-induced UDP-GT was low in the youngest rats. It was about 180% in two-month-old rats and reached 260% of the control value in eight-month-old rats. Although the activity decreased in the older rats, it still exceeded 200%. Dexamethasone did not affect UDP-GT activity. Only in two-week-old and two-month-old rats did we observe a slight increase in the activity of UDP-GT.
Plewka
A
A
Department of Histology and Embryology, Silesian School of Medicine, Katowice-Ligota, Poland.
Kamiński
M
M
Plewka
D
D
D000375:Aging / Q000378:metabolism*; D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D004790:Enzyme Induction; D014453:Glucuronosyltransferase / Q000096:biosynthesis*; D008297:Male; D010634:Phenobarbital / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D019324:beta-Naphthoflavone / Q000494:pharmacology*
D019324:beta-Naphthoflavone; D003907:Dexamethasone; D014453:Glucuronosyltransferase; D010634:Phenobarbital