title: Effect of exogenous ascorbic acid intake on biosynthesis of ascorbic acid in mice.
abstract: The effect of exogenous ascorbic acid intake on biosynthesis of ascorbic acid in mice has been studied. After the mice were on diets containing added ascorbic acid for two months, the activities of ascorbic acid synthesizing enzymes in the mouse liver homogenates were measured using L-gulono-gamma-lactone as a substrate. Exogenous ascorbic acid intake (0.5, 1 or 5% in the diet) was able to increase the concentration of ascorbic acid in the blood and to decrease the activities of ascorbic acid synthesizing enzymes in mouse liver. The results suggest that ascorbic acid synthesis was controlled by local regulatory mechanism or by the concentration of ascorbic acid in the hepatic portal blood. Ingestion of dietary erythorbic acid, a stereoisomer of ascorbic acid, had no effect on the activities of ascorbic acid synthesizing enzymes.
authors.affiliation: Linus Pauling Institute of Science and Medicine, Palo Alto, California 94306.
authors.forename: C S
authors.initials: CS
authors.lastname: Tsao
authors.forename: M
authors.initials: M
authors.lastname: Young
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000032:analysis / Q000096:biosynthesis / Q000494:pharmacology*; D004032:Diet; D005260:Female; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012737:Sex Factors; D013237:Stereoisomerism
chemical_list: C005056:isoascorbic acid; D001205:Ascorbic Acid