ASPHYXIA OF THE FROG'S KIDNEYS

Abstract

When normal frogs were deprived of O2 the formation of urine ceased. This was studied in frogs whose cloacas were bound for varying periods of time during and after the absence of O2. At 22[degree] C. only 4% of an atmosphere of O2 was required to maintain normal urine formation. The anuria produced could not be overcome by conditions that ordinarily induce diuresis. After pithing frogs, the blood flow in the kidneys was examined, and it was found that removal of O2 stopped the flow in all glomeruli; resupply of air or of 4% O2 brought prompt resumption of this flow. This stoppage was not due to any property of the general circulation but depended upon selective constriction of renal afferent arterioles. The response was not modified by denervation of the kidney. Recovery depended chiefly on the bringing in of O2 by the blood in the renal-portal system. Intermittent and permanent states of blood flow in the glomeruli were not influenced by O2 tensions that failed to constrict the renal arterioles. Proteinuria did not result from partial or complete asphyxia. The selective effect of asphyxia reproduced precisely the well-known effects of ligating the renal arteries.