Prolonged exposure of young rats to an oxygen atmosphere at reduced pressure

¹ Department of Physiology, The Ohio State University, Columbus, Ohio

The effect was studied of exposing 12 young male white rats to an atmosphere almost free of nitrogen but with an alveolar Po₂ the same as that of the 12 control animals breathing ambient air. This was achieved by keeping the experimental animals in almost pure oxygen at a reduced pressure. Experimental and control animals were in closed chambers with oxygen being supplied from a spirometer while Co₂ was absorbed. Humidity and temperature were closely regulated. Provision was made for handling the animals and supplying them with food and water without changing the chamber environment. A successful experiment lasting 24 days was completed, not including observation periods of 6 days be-before and 8 days after the experiment when both groups were kept in air. No consistent difference was noted in rate of growth, oxygen consumption, food consumption, water intake, hemoglobin concentration, or behavior of the two groups. A decreased rate of urine production by the rats in the experimental group was attributed to an increased evaporative loss of water in the rarified atmosphere.

Submitted on March 20, 1963