Assay of ACTH activity based on the eosinopenic response in normal and hypophysectomized mice.

Abstract

Since 1937, a number of assay procedures for ACTH have been proposed. These have generally been based upon a change in size of the adrenal glands of normal rats and baby chicks, or changes in the adrenal glands of hypophysectomized animals. The hypophysectomized rat has been the animal of choice, and the effect of ACTH on adrenal repair, maintenance, ascorbic acid or cholesterol levels have been used as end points in the assay. The ascorbic acid depletion test proposed by Sayers, et al. (1948) has proved to be the most satisfactory one. It is an extremely sensitive test, reasonably accurate and very useful in detecting small amounts of hormone in body fluids. (Gemzell, 1952.) At the present time, the role of ascorbic acid in the synthesis or release of adrenal cortical hormones is unknown (Sayers, 1950). The factor in the ACTH that brings about the change in ascorbic acid level,