Vascular Volume,Blood Flow,and Resistance in Dog Kidneys During Constriction of the Renal Artery ∗

Abstract

Summary

The vascular volume in dog kidneys was determined by combining injections into the renal artery of ¹³³Xe and ¹³¹I-albumin with an external counting technique. During control periods, where the renal blood flow averaged 5.2 ml/g ∗min, the vascular volume was 25 ml/100 g of cortex. In the present investigation the vascular volume was systematically overestimated, by a few percent, for technical reasons.

Constriction of the renal artery resulting in a fall in the perfusion pressure from 117 to 65 mm Hg caused no change in the blood flow. The decrease in resistance during constriction of the artery was followed by a dilation of the renal vessels, and the vascular volume in the kidney rose from 25 to 34 ml/100 g, when the artery was stenosed. A dilation reflected by this volume change indicates that other vessels than the afferent arterioles expand their volumes, and suggests the possibility that the postglomerular resistance most likely is also reduced.