THE IN VITRO HYDROXYLATION OF 21-CARBON STEROIDS BY RAT ADRENAL GLANDS1

Abstract

MARKED species variations in the relative proportions of 17a-hydroxycorticosterone (cortisol) and corticosterone in mammalian adrenocortical secretions have been reported (1, 2). Some animals, like the monkey, appear to secrete primarily cortisol, while others, like the rabbit, primarily corticosterone. A third group of animals, of which the dog is representative, secretes a mixture of the two hormones, with cortisol usually occurring in somewhat greater quantities. In the case of the laboratory rat, most investigators have found that this species secretes corticosterone, aldosterone and a varying number of unidentified substances but no readily detectable quantities of cortisol (1, 3, 4, 13). The present study was undertaken in an attempt to discover the reason for the impaired ability of the rat to hydroxylate cortical steroids at carbon 17. In this regard, it was felt that observations relating to the capacity of the rat adrenal cortex to hydroxylate a variety of 21-carbon steroids under in vitro conditions might prove informative. The following experiments were accordingly performed.