[Effect of prolonged ingestion of tannic acid, potassium metabisulfite and ethanol, administered alone or in combination, on the liver vitamin A concentration in the rat].

Young male rats were alloted to 23 factorial arrangement to dietary treatments. The eight dietary treatments were: 1) standard semi-synthetic diet (R); 2) stand diet with 1 p. 100 potassium bisulfite (S); 3) standard diet with 3,2 p. 100 tannic acid (T); 4) standard diet with sulfite and tannic acid (ST); 5) standard diet in which ethanol took place of 30 p. 100 of the carbohydrate calories (E); 6) standard diet with sulfite and ethanol (SE); 7) standard diet with tannic and ethanol (TE); 8) standard diet with sulfite, tannic acid and ethanol (STE). After two and six months, the hepatic levels of vitamin A were determined. Factorial analysis of variance was employed in evaluating main effects of the three compounds and their interactions. Tannic acid, alone or associated with sulfite and/or ethanol caused a marked decrease of the concentration of vitamin A after two months, and still more important after six months. The influence of tannic acid on the absorption of vitamin A is discussed. An interaction between sulfite and tannic acid is observed: without tannic acid, sulfite caused a slight but significative increase of vitamin A, but with tannic acid sulfite caused a non-significative decrease of vitamin A. Ethanol had no effect on the store of hepatic vitamin A, but a slight and significative main effect in increasing the concentration.