EFFECT OF SEX AND STRAIN OF RATS ON INVITRO RESPONSE OF ADRENOCORTICAL TISSUE TO ACTH STIMULATION

Various attempts to demonstrate the effects of ACTH on corticosterone production by whole adrenal tissue from female rats of the Wistar strain, using methods based on those of Saffran and co-workers, have failed despite use of a variety of incubation conditions and methods for steroid measurement. The finding that testosterone in similar incubations was nevertheless satisfactorily stimulated suggested that the lack of effect on corticosterone was not due to inaccessibility of the tissue to ACTH or metabolism of ACTH by the tissue. Comparison of corticosterone and testosterone production in response to ACTH by adrenals from male and female rats of the Wistar, Lister and Sprague-Dawley strains show that in all cases the response of male tissue was far greater than female; indeed of the female glands, only those from Sprague-Dawleys showed a significant stimulation in corticosterone production with ACTH. Testosterone production, however, although much lower in amount, was stimulated similarly in male and female glands in Wistars and Sprague Dawleys, and was unstimulated in all Lister incubations. 18-Hydroxydeoxycorticosterone was not stimulated by ACTH in either male or female Wistar tissue, or in male Sprague-Dawley adrenals. Use of a cell suspension prepared by collagenase treatment eliminated the difference in response of corticosterone to ACTH in male and female Wistar adrenal tissue, and also allowed stimulation of 18-hydroxydeoxycorticosterone by ACTH. The results, which are borne out by reports in the literature, suggest that female rat glands contain substances which inhibit the response of corticosterone but not testosterone to ACTH, and that glands from both sexes contain inhibitors to stimulation of 18-hydroxydeoxycorticosterone. These inhibitors are eliminated by protease treatment. © 1978.