The Effect of Maternal Ethanol Ingestion on Fetal Vitamin A in the Rat

Abstract

ABSTRACT. The effect of maternal ethanol ingestion on fetal tissue vitamin A was investigated. Pregnant rats were pair-fed control diets or diets containing 36% of energy as ethanol. After 17 or 21 d gestation, fetuses were removed and fetal and maternal tissues were analyzed by HPLC for retinol and retinyl palmitate. Ethanol consumption resulted in fewer fetuses per pregnancy, increased number of resorption~, and increased numbers of gross fetal abnormalities. In maternal tissues, ethanol consumption resulted in greater lung and kidney vitamin A concentrations. In the fetuses of ethanol-consuming pregnancies, free retinol in liver was higher at d 17. However, fetal liver palmitate levels and total retinyl palmitate in liver, lung, and kidney were lower in ethanol-fed rats at d 21 of gestation. Fetal lung retinyl palmitate concentrations were greater at both d 17 and d 21, and kidney levels were also greater at d 21. Ethanol consumption during pregnancy results in an increased incidence of spontaneous abortions (I), an increase in perinatal mortality (2), and a number of congenital malformations (3). The major features of these congenital malformations (FAS) are intrauterine and postnatal growth retardation, craniofacial dysmorphology, congenital heart defects, skeletal anomalies, and CNS dysfunctions (4).Controversy in the literature still exists over the exact mechanism by which ethanol causes FAS. Some believe ethanol and/ or acetaldehyde have a direct teratogenic effect. The other view is that the abnormalities observed are the result of altered maternal or placental physiology or other nutritional deficiencies caused by the ethanol ( 5 , 6).The interaction of ethanol with vitamin A is a complex interaction. It is known that in both man and animals, chronic consumption of ethanol results in very low levels of liver vitamin A reserves. This can occur despite adequate intake and normal plasma levels of this vitamin (7-10). The pattern of fetal anomalies associated with vitamin A deficiency is similar in some respects to that of FAS (1 l), including frequently observed defects of growth, craniofacial, neurologic, urogenital, and heart systems. Therefore, it is conceivable that vitamin A deficiency could be present in FAS.The purpose of our research was to determine if maternal ethanol ingestion had an effect on fetal tissue vitamin A in the rat. We found that fetal vitamin A was significantly decreased in liver, but elevated in lung and kidney. Total vitamin A stores were lower in fetuses born of pregnant dams ingesting ethanol for the 2 1 d of gestation. MATERIALS AND METHODS Alcohol diet and experimental animals. Female timed-preg-nancy Sprague-Dawley rats (Harlan Industries, Indianapolis, IN) were weighed, randomly assigned to groups on d 1 of pregnancy, and kept in individual mesh-bottom cages in a controlled temperature environment with a light-dark cycle of 12 h light, 12 h dark. The rats were fed an isocaloric liquid Lieber-DeCarli diet (Dyets, Inc., Bethlehem, PA) containing 25% protein, 63% carbohydrat...

Prenatal Ethanol Consumption Increases Retinol and Cellular Retinol-Binding Protein Expression in the Rat Fetal Snout

“…The diet and feeding method are devised to ensure adequate and equivalent calorie, protein and general nutrient intake. Using this model, we have previously shown that ethanol consumption by the pregnant rat dam results in equal or only slightly reduced maternal weight gains for the first 19-20 days of gestation [17]. There is also no difference in the serum retinol concentrations between the pregnant dams consuming the control and ethanol diets [20].…”

“…The ethanol diet used was identical to that published previously [17,18]. Pregnant Sprague-Dawley (Harlan Industries, Indianapolis, Ind., USA) rats were randomly assigned to groups on gestational day 1 of pregnancy and kept in individual mesh-bottomed cages in a controlled temperature environment with a light-dark cycle of 12 h. The rats ate an isocaloric liquid Lieber-DeCarli diet by drinking from a Richter feeding tube (Dyets Inc., Bethlehem, Pa., USA), containing 25% protein, 63% carbohydrate and 12% fat.…”

“…Rats on the control liquid diet were pair fed, starting with the same volume as ethanol fed on day 1, then receiving the average amount of food consumed by the ethanolfed rats the previous day. Food intake was recorded daily, maternal weight was obtained at the beginning and end of the experiment and the average fetal weight in each litter was obtained on the day the rats were killed, as previously published [17]. At 20 days of gestation of a normal 22-day pregnancy, 6 controldiet-fed rats and 8 ethanol-diet-fed rats were alternately anesthetized with ether, after which the fetuses were removed from the uterus, weighed and decapitated.…”

“…Snout tissue used for retinol and retinyl palmitate analysis was homogenized and extracted using a previously established chloroform/methanol procedure [17,18]. Chloroform extracts were assayed by HPLC (Pecosil C18, 5 Ìm, 15 cm) at a wavelength of 325 nm.…”

“…The striking overlap in the phenotypic embryopathy of FAS and that which occurs in vitamin A toxicity or deficiency, as well as studies demonstrating an interaction of ethanol with vitamin A [12][13][14][15][16] has led us to hypothesize that ethanol might alter the vitamin A metabolism or function which could produce embryonic derangements that manifest as development abnormalities seen in FAS. We are pursuing this question in the ethanol-consuming pregnant rat model [17][18][19][20] and have recently reviewed the subject [21].…”