Development of hepatic bilirubin glucuronidation as affected by prolonged maternal ethanol intake.

Prolonged maternal ethanol intake by lactating mothers resulted in a 26% and 41% decrease in serum conjugated bilirubin of 6 and 10 day old suckling newborn rats, respectively. An increase of 20% and 36% was observed in the serum unconjugated bilirubin levels in suckling newborns from the ethanol-fed group compared to the corresponding controls. Newborns suckling on ethanol-fed dams showed a small, but significant hyperbilirubinemia compared to the controls. Acute administration of ethanol (2.5 g/kg) to newborn rats also resulted in a decrease in serum conjugated bilirubin and an increase in the levels of unconjugated and total bilirubin. Prolonged ethanol intake by adults also resulted in a decrease in conjugated bilirubin and an increase in unconjugated and total bilirubin levels compared to the corresponding controls. Bilirubin glucuronide formation in the liver was decreased by ethanol by about 30% and 37% in the suckling newborn, and adults, respectively. Newborns suckling on ethanol-fed dams, as well as the dams consuming ethanol showed an increase in hepatic (UDPG)/(UDPGA) levels. The activity of hepatic bilirubin-UDP-glucuronyl transferase either in the newborns suckling on ethanol-fed dams, or in dams consuming ethanol chronically, was not significantly different from their corresponding controls. Ethanol was found to inhibit the glucuronidation of bilirubin by decreasing the availability of UDP-glucuronic acid in the newborn and adult livers.