Influence of dietary lipids on glucuronidation and sulfation of phenol and its para substituent in the rat.

Rats were fed corn oil-free or corn oil-containing diets for 4 weeks to determine their effect on the competition between glucuronidation and sulfation in phenol and its para substituents. The activities of uridine diphosphate-glucuronyltransferase (UDPGT) on chemicals were enhanced with a 12% corn oil diet, whereas sulfotransferase activity showed no significant change. Following the intravenous injection of p-ethylphenol and p-tert-butylphenol, an increase of glucuronide and a decrease of sulfate were observed in the rats fed the corn oil diet. In contrast, no significant changes were observed in phenol and p-phenylphenol. These results are discussed in association with van der Waals volume (Vw) of substituent and phospholipid dependence of UDPGT.