Phase II biotransformation of carcinogens/atherogens in cultured aortic tissues and cells. II. Glucuronidation of 3-hydroxy-benzo(a)pyrene.

Avian aortic tissues contain active UDP-glucuronosyltransferase(s) (EC 2.4.1.17) which catalyze(s) the glucuronidation of 3-hydroxybenzo(a)pyrene and p-nitrophenol. Activities were compared in abdominal segments (susceptible to the atheroma-promoting effects of polynuclear aromatic hydrocarbons) vs. thoracic segments (susceptible to the atheroma-initiating effects of polynuclear aromatic hydrocarbons). Activities measured in the abdominal segments were approximately 8-9-fold higher than those measured in thoracic segments from the same cockerels. Surprisingly, pretreatment of cockerels with phenobarbital, but not 3-methylcholanthrene, resulted in small (60-120%) but consistent increases in glucuronosyltransferase activities in both aortic segments. Activities were readily detectable in microsomal fractions of both segments and in cultured smooth muscle cells derived from aortic segments, but were not detectable in cultured endothelial cells. Avian aortic microsomal glucuronosyltransferases exhibited minimal or no response to the effects of several common activators of hepatic microsomal glucuronosyltransferases.