An improved assay technique for uridine diphosphate glucuronosyltransferase activity towards 5-hydroxytryptamine and some properties of the enzyme

A simplified and sensitive procedure for the routine assay of UDP-glucuronosyltransferase activity towards 5-hydroxytryptamine (serotonin) was developed and the reaction product confirmed as the O-glucuronide of this substrate. The assay was used to study some properties of this UDP-glucuronosyltransferase activity. In mouse liver activity was stimulated by membrane-perturbation procedures and by UDP-N-acetylglucosamine. In rat liver it was stimulated by digitonin, but not by diethylnitrosamine. Mouse duodenum, kidney, and lung possessed activity that was less latent than in liver. No activity was found in homogenates of brain. The activity was present in Gunn rat liver, though only one-third of that in Wistar rat liver. Cat liver contained no UDP-glucuronosyltransferase activity towards 5-hydroxytryptamine.