Influence of Hypoxia on Renal Circulation and on Excretion of Electrolytes and Water

Abstract

Response of the kidney to hypoxia created by perfusion with venous blood obtained from the right ventricle was studied in anesthetized dogs. A pump aided in supplying the blood with an adequate head of pressure. The advantage of the method was that it permitted a specific hypoxia to be imposed upon the kidney with minimal disturbance to the organism as a whole. Blood oxygen content in different expts. varied from 6.7 to 15.9 vol. % during venous perfusion (avg. 10.7). The most consistent response was an increase in PAH clearance, in one instance as great as 92%, but averaging 22%. Renal vascular resistance showed a typical reduction during hypoxia. The nature of the hyperemia has not been elucidated. Creatinine clearance characteristically decreased by an avg. of 10%. The net effect was therefore a reduction in the filtration fraction. The usual response in the excretion of Na, K and water was an increase. Because excretion increased while filtration rate declined in several expts., the conclusion followed that hypoxia had impaired slightly the tubular reabsorptive processes of these substances.