Protein Metabolism in the Mammalian Kidney

The concentrations of amino acid and polypeptide nitrogen in plasma samples from the aorta, renal vein, and inferior vena cava of the rabbit have been determined. It was demonstrated that there were significantly higher concentrations of amino acids and polypeptides in the renal vein than in either aorta or inferior vena cava. The possible implications of these findings in relation to the role of the kidney in protein metabolism has been discussed.