Renal vasodilatation: effect on renal handling of phosphate.

Abstract

1. The combined effects of unilateral renal vasodilatation produced by acetylcholine or bradykinin and intravenous infusion of angiotensin on phosphate excretion and reabsorption were investigated in fourteen anaesthetized dogs. The influence of these manoeuvres on the excretion of sodium, calcium and magnesium was also evaluated. 2. Unilateral renal vasodilatation alone produced an increase in the excretion of phosphate, calcium, magnesium and sodium; and the infusion of angiotensin caused further augmentation of the excretory rates of these ions from the vasodilated kidney in most experiments. 3. The maximal tubular reabsorptive capacity (Tm) for phosphate was decreased by renal vasodilatation. 4. There was a close and significant correlation between the fraction of the filtered load of phosphate, calcium, and magnesium which was excreted and that of sodium. 5. The results indicate that renal vasodilatation with or without the infusion of angiotensin causes a decrease in the renal tubular reabsorption of phosphate, calcium, magnesium and sodium.