The effect of vitamin E administration on increased urinary excretion of porphyrins and porphyrin precursors induced by ethanol administration was studied in rats. Increases in the urinary excretion of δ-aminolevulinic acid, porphobilinogen, and coproporphyrins occurred in rats fed ethanol for a period of 14 days. The administration of vitamin E prevented the ethanol-induced increases in the urinary excretion of coproporphyrins but not of δ-aminolevulinic acid and porphobilinogen. Activities of hepatic δ-aminolevulinate synthase and δ-aminolevulinate dehydratase were not found to be enhanced when the ethanol-fed rats were sacrificed after 12 hours of fasting. Vitamin E administration did not prevent the induction of cytochrome P-450 by ethanol. The specific interference of vitamin E administration with the ethanol-induced increases in the urinary excretion of coproporphyrins remains unexplained.
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