Renal transport of cystine by isolated renal tubules and brush-border membrane vesicles

Abstract

Human cystinuria, an inherited disease characterized by increased excretion of cystine and the dibasic amino acids, lysine, ornithine, and arginine, has focused attention on the nature of the renal tubule reab-sorption of these amino acids. In 1951, Dent and Rose1 proposed that cystine and the dibasic amino acids were handled by a common system in the kidney that was defective in human cystinuria. This hypothesis was strengthened by the fact that lysine infusion in both man2,3 and dog4 increased the excretion of cystine and the other dibasic amino acids. A common system for the accumulation of dibasic amino acids in renal tubule cells has been demonstrated using cortical slices from both human5 and rat kidney6. Further support for a common system came from microperfusion studies in rat proximal tubules, demonstrating arginine inhibition of cystine uptake from the tubule lumen7.