OXYGEN TENSION AND URINE PRODUCTION IN FROGS

Abstract

Rates of urine formation were measured at O tensions of 0-1 atm. (20[degree] to 24[degree]) in 3 kinds of frogs: normal, pithed, and pithed with viscera exposed. In the latter kind one ureter was cannulated so that sudden changes in rate of excretion could be correlated with the observed flow of blood in the glomeruli. Normal frogs formed urine nearly independently of O tension except in tensions below that of room air. Pithed frogs formed relatively little urine even in pure O; they were not breathing. Pithed frogs with ureter cannulated formed urine comparatively slowly in room air, but 1/2 atm. of O was sufficient to yield nearly max. rates of excretion. Modifications of the glomerular blood flow, of mean arterial pressure, and of heart rate, were not proportional to water excretion. While lack of blood flow through the glomeruli stopped urine formation, the presence of rapid blood flow did not insure it.