Adrenal Function During Prolonged Exposure to Low Concentration of Carbon Dioxide

Abstract

Adrenal-pituitary interrelationship was studied during prolonged exposure to 1.5% CO2 for 42 days in normal and hypophysectomized rats, and normal guinea pigs. During exposure to CO2 animals were killed during 2 periods: 11-15 days and 28-42 days of exposure to 1.5% CO2. In normal and hypophysectomized rats adrenal cortical activity was increased during both experimental periods of CO2 exposure and in the following recovery period on air. This was indicated by a significant decrease of adrenal cholesterol and a significant eosinopenia and lymphopenia in normal and hypophysectomized rats. Adrenal ascorbic acid content, studied only in normal rats, was significantly reduced during exposure to CO2; but returned approximately to the initial level during a 10-day recovery period on normal air. In guinea pigs adrenal cortical activity was increased only during the 28-42-day period of exposure to 1.5% CO2, as shown by a significant eosinopenia and lymphopenia as well as in a decrease of the adrenal cholesterol content. In both rats and guinea pigs, blood sugar was maintained at a normal level, apparently, at the expense of the liver and muscle glycogen stores. Liver glycogen returned to pre-exposure levels during a 10-day recovery period, in contrast to muscle glycogen, which remained at a lower level.