Alterations in Histidine Catabolism in Normal Rats Given Pharmacological Doses of Folic Acid and Cyanocobalamin 1

Summary

Following administration of his-tidine (imidazole-2-¹⁴C) to normal rats given pharmacological doses of cyanocobalamin the initial rate and amount of ¹⁴CO₂ excreted in the breath is significantly increased while in normal rats given pharmacological doses of folic acid these measurements are decreased as compared to normal untreated rats. These results indicate that pharmacological doses of cyanocobalamin increase and folic acid decrease either the rate of physical transport of histidine to intracellular sites of catabolism or the fractional rate describing the actual biochemical steps involved in such catabolism.