THE EFFECTS OF STRESS, ADRENAL AND ADRENOCORTICOTROPHIC HORMONES ON THE CIRCULATING EOSINOPHILS OF MICE1

Abstract

A direct procedure for determining eosinophils in mice and rats is presented along with a modified procedure for staining blood films in coplin jars. A method of obtaining blood from mice is descr. in detail. This method gave reasonably consistent eosinophil counts when succeeding drops of blood were taken from the tail. The Standard error of this procedure was 1.7 times the square root of the number of eosinophils counted. These technics were applied to male mice and rats and the following results obtained: In normal mice, mild stress or epinephrine injns. produced a great decrease in the number of circulating eosinophils. This eosino-penia lasted for approx. 7 hrs. and was followed by a period of eosinophilia. By increasing the amt. of stress, a greater decrease in eosinophils occurred lasting over a longer period of time. Removal of the adrenal cortex prevented the eosinopenia due to stress and epinephrine; instead a slight eosinophilia occurred after each detn. However, the eosinopenia was obtained after injns. of adrenal cortical hormones. The degree of response was correlated with the amt. of hormone injected. Sex hormones, oils, and low doses of desoxycorticosteroids did not produce an eosinopenia in adrenalectomized mice. Evidence was presented that the change in the number of circulating eosinophils can be used to determine whether the animal has functional cortical tissue present. If a decrease of 30% or more in the number of circulating eosinophils occurs, then there is sufficient adrenal cortical tissue present to maintain the mouse after removal of the excess salt in its drinking water. The spleen is not involved in the rapid decrease in the circulating eosinophils, nor in the eosinophilia of adrenalectomized mice. In hypophy-sectomized mice, stress and epinephrine produced a decrease of from 40% to 50% in the number of circulating eosinophils. ACTH produced a greater effect, averaging an 87% decrease when 50 [mu]g. were injected.