Amino Acid Metabolism in Rats Fed a High Protein Diet without Pyridoxine

Publisher Website
Google Scholar
Abstract
Metabolism of amino acids was studied in rats fed 70% casein with or without supplemented pyridoxine. Analyses of nitrogenous compounds in the urine showed no difference in the total nitrogen and creatinine, whereas decreased excretion of urea and ammonia in the pyridoxine-depleted rats was observed. Urinary excretion of cystathionine was remarkable in reflecting the sensitivity of cystathionase to pyridoxine depletion. In the pyridoxine-depleted animals, higher levels of threonine and glycine were found in the livers, and plasma and those amino acids were excreted in greater amounts. The alanine content in the livers of the pyridoxine-deficient rats was decreased as a result of an increased consumption of alanine in the livers. The incorporation of 14C-leucine into liver proteins was not inhibited in the pyridoxine-depleted rats.