A postabsorption effect of L-ascorbic acid on copper metabolism in chicks.
We have studied the effect of L-ascorbic acid (vitamin C) on copper metabolism using copper-deficient chicks and the activation of lysyl oxidase copper-dependent enzyme, to assess bioavailability of copper. When administered intraperitoneally with (or 75 minutes before) CuSO4, L-ascorbate significantly impared the effectiveness of copper to restore lysyl oxidase activity in deficient chicks. L-ascorbate given 75 minutes after CuSO4 (i.e., in the post-absorption period), however, produced a substantial increase in copper-induced enzyme activation. L-ascorbate by itself showed no direct stimulating effect in deficient chicks. When the L-ascorbate was given to chicks that had received adequate dietary copper, there was a strong rise in ceruloplasmin and a slight, but significant increase in lysyl oxidase. An increase in ceruloplasmin in response to copper was also seen in deficient chicks and L-ascorbate also augmented that increase. Substituting D-isoascorbic acid for antagonistic properties of L-ascorbic acid on copper metabolism, but they also reveal possible sterospecific postabsorption roles for L-ascorbate in the metabolism of copper.
D000042:Absorption; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D002570:Ceruloplasmin / Q000378:metabolism; D002645:Chickens / Q000378:metabolism*; D003300:Copper / Q000172:deficiency / Q000378:metabolism* / Q000494:pharmacology; D019327:Copper Sulfate; D004790:Enzyme Induction / Q000187:drug effects; D007700:Kinetics; D008249:Protein-Lysine 6-Oxidase / Q000096:biosynthesis; D013431:Sulfates / Q000494:pharmacology; D013997:Time Factors
D013431:Sulfates; D003300:Copper; D002570:Ceruloplasmin; D008249:Protein-Lysine 6-Oxidase; D019327:Copper Sulfate; D001205:Ascorbic Acid