Inhibitory effect of hydrocortisone and analogues on adrenocortical secretion in dogs

An isolated perfused adrenal gland preparation in the dog was used to study the effect of perfusion of exogenous steroids on endogenous adrenal secretion. ACTH was infused throughout each experiment to ensure maximal endogenous steroidogenesis. It was found that hydrocortisone and two of its analogues (Δ1-hydrocortisone and Δ1, 9α-fluoro, 16-methyl hydrocortisone) when perfused at concentrations of 100, 200, and 400 µg/ml inhibit the endogenous secretion of hydrocortisone and corticosterone. Corticosterone at the same concentrations inhibited only corticosterone secretion.