Specificity of the Inhibition of Tubular Phosphate Reabsorption by Certain Amino-acids

Abstract

THE activity of the transport mechanisms which regulate the renal tubular reabsorption of phosphate is dependent on a number of factors. Of paramount importance is parathyroid hormone which acts to decrease phosphate reabsorption in the proximal tubule, or possibly to bring about phosphate secretion into the tubular lumen at a more distal site. The role of vitamin D on the phosphate reabsorptive process is not clear: at moderate or low doses, the effect is to increase phosphate reabsorption, while larger doses have a phosphaturic action. The effects of vitamin D on phosphate reabsorption may be related to a direct tubular action, or may be mediated indirectly through its effect on parathyroid function or citrate metabolism.