URIDINE DIPHOSPHATE-GLUCURONOSYLTRANSFERASE ACTIVITIES IN RAT-BRAIN MICROSOMES

The glucuronidation capacity of rat brain microsomes was investigated using a series of chemically related phenolic compounds and fatty acid s which are usually glucuronidated in vivo. Most of the phenols assaye d were glucuronidated, but no glucuronide formation was detected for s tearic and alpha-linolenic acids, 4-methylphenol, bilirubin, morphine, dopamine and serotonin. The activity of uridine diphosphate-glucurono syltransferase (UGT) towards 1-naphthol represented 0.28% of that obta ined with liver microsomes. The inhibitory effects on the formation of 1-naphthol glucuronide of some endogenous and exogenous substances we re investigated. The results suggest that only the isoform of UGT conj ugating 1-naphthol is present in rat brain.