Experimental Galactose Toxicity: Effects on Synaptosomal Phosphatidylinositol Metabolism

Abstract Experimental galactose toxicity was induced by weaning rats onto an isocaloric 40% galactose diet. Synaptosomes were prepared from cerebra of rats at 2-9 weeks post-weaning and incubated with ³³P]P_i and myo -2-³H]inositol in the presence or absence of 0.2 mM-acetylcholine. The acetylcholine-stimulated ³³P]P_i labeling of phosphatidylinositol and the changes in amounts of phosphatidylinositol were similar in the normal and galactose-toxic rats; however, acetylcholine-stimulated myo -2-³H]inositol labeling of phosphatidylinositol was markedly decreased in the galactose-toxic rats. The impairment of acetylcholine-stimulated myo -2-³H]inositol incorporation into phosphatidylinositol observed after 2 weeks on the diet did not vary after more prolonged exposure to galactose.