PRENATAL ETHANOL EXPOSURE ALTERS THE EXPRESSION OF INTESTINAL HYDROLASE MESSENGER-RNAS IN NEWBORN RATS

To gain insight into the postnatal growth delay induced by ethanol in utero, we characterized functional impairments of the small intestine of neonatal rats prenatally exposed to ethanol using a well-described model of gestational alcoholism (25% ethanol w/v in the drinking water ). Expression of the intestinal enzymes-lactase-phlorizin hydrolase (L PH) and intestinal alkaline phosphatase (IAP)-that are critical for en teral nutrition of neonates was studied. Characteristic patterns of LP H and IAP expression along the proximal-distal (horizontal) and clypt- villus (vertical) axes of the small intestine, as well as the intracel lular localization of LPH and IAP mRNAs and immunoreactive proteins wi thin absorptive enterocytes, were not altered by prenatal exposure to ethanol. However, a 10- to 15-fold increase in the number of LPH and I AP mRNA molecules per absorptive enterocyte was found throughout the i ntestine of ethanol-exposed neonates, compared with controls, whereas lactase and alkaline phosphatase activities per enterocyte remained un changed. These findings suggest that ethanol in utero alters the mRNA abundance of epithelial enzymes in newborn rat small intestine. Change s in mRNA abundance could be an important aspect of enterocyte adaptat ion to high ethanol concentrations in gastrointestinal amniotic fluid of ethanol-exposed fetuses.