Influence de la vitamine A sur la distribution des glycosaminoglycanes dans les tissus du rat

Abstract

Glycosaminogly cans (GAG) from brains, intestines, livers and skin of rats were analyzed by electrophoretic and enzymatic methods. Variations in GAG distribution have been studied in rats fed on a vitamin-A-deficient diet and on a diet supplemented with an excessive quantity of vitamin A. Hypervitaminosis A resulted in a decrease in GAG isolated from connective and hepatic tissues. The incorporation of labeled sulfate into the GAG of these tissues has been studied. Hypervitaminosis A resulted in a decrease in sulfate incorporation into the GAG isolated from connective tissues. A large increase in sulfate incorporation into the GAG of the digestive tract is observed for vitamin-A-treated rats. A decrease is noted for vitamin-A-deficient rats. It was suggested that these variations in distribution and specific activity of GAG could be due to different effects of vitamin A. Vitamin A seems to be required either for the release of lysosomal enzymes or for the sulfatation and elongation of certain glucidic chains in the biosynthesis of sulfated GAG.