Effects of Acute Intermittent Anoxia Upon Urinary Volume, Specific Gravity and Chloride

Summary The first hour exposure of rats to 258 mm Hg barometric pressure resulted in a 3 to 11 (average 7) fold increase in urine production. This increase in volume was accompanied by a marked fall in specific gravity (1.004 to 1.012, average 1.008). At the end of the third hour of intermittent anoxia the urinary volume and specific gravity approached normal sea level values. The chloride content, on the other hand, was greatest in the very dilute and abundant urine of the first hour and the chloride content decreased on repeated exposures until the more concentrated urine of the third hour contained practically no chloride.