Induction and immunological characterization of the uridine diphosphate-glucuronosyltransferase conjugating 1-naphthol in the rat choroid plexus

The uridine diphosphate-glucuronosyltransferase isoform conjugating 1-naphthol has a very high activity in the rat choroid plexus. We showed that antibodies raised against the main liver isoenzyme cross-reacted with a choroidal protein exhibiting the same molecular weight as the hepatic form. Both enzymes had a similar affinity for 1-naphthol. After an in vivo treatment by 3-methylcholanthrene, a 3-fold increase of the activity in both the liver and choroid plexuses was observed. These results suggest that the choroidal and hepatic enzymes conjugating 1-naphthol are identical. This high metabolic activity suggests a metabolic protection of the brain by the choroid plexus.