Localization of amino-nitrogen reabsorption in the nephron of the dog

Abstract

Utilizing the stop-flow method of analysis, we have observed that a series of amino acids, including glycine, l-alanine, d, l-alanine, l-glutamic acid, l-lysine, and l-arginine, is actively reabsorbed in the proximal part of the nephron of the dog. Reabsorption is maximal within that portion of the nephron where the secretion of p-aminohippurate is greatest. The reabsorption of arginine is reduced by the infusion of both lysine and ornithine. We conclude that the same cells of the proximal tubules reabsorb a variety of amino acids, and that the three basic amino acids, mentioned earlier, are reabsorbed by a single transport mechanism within a given tubular cell, or, at least, have some common step in their individual transport mechanisms.