Comparison of Epinephrine and ACTH Action on the Circulating Eosinophils of Mice

Abstract

Twenty-nine out of 35 BBF1 male mice showed an eosinopenic response to 20 ug. of epinephrine a month or more after adrenalectomy. The avg. response was -37%. In a similar group of mice injd. with 4 I U of ACTH only 15 animals showed an eosinopenic response. The avg. response of the 34 animals was 6%. A 2d injn. of epinephrine 4 hrs. after the 1st failed to produce a significant eosinopenia in any of the adrenalectomized mice. These animals were also found to be refractory to ACTH injns., to numerous nonadrenal steroids and to control solns. Following a subcut. injn. of 4 I U ACTH, additional injns. of ACTH or epinephrine produced an eosinopenia in most of the animals. Thus the eosinophiis did not become refractory following an injn. of ACTH as they did following the admn. of epinephrine. Epinephrine probably acts directly on the adrenal cortex in the mouse and its action is not necessarily dependent upon a prior release of ACTH.