Pharmacodynamic properties of adrenal cortical extracts in comparison to synthetic corticosteroid mixture in the rat.

The effects of a total extract of adrenal cortex on corticosterone and ACTH plasma levels have been studied in the rat, either during circadian rhythms or in conditions of stress, in comparison to the effects of a synthetic corticosteroid mixture. A total extract of adrenal cortex, acutely and chronically administered at low and high doses, showed an inhibitory effect on plasma steroids and ACTH, whereas a synthetic corticosteroid mixture was more effective in producing such an inhibition. On the other hand, rats treated with a total extract of adrenal cortex responded better to stress than animals treated with a synthetic corticosteroid mixture. This difference may be due to the presence in the total extract of the adrenal cortex of certain substances having stimulatory properties on the steroidogenesis and/or on the activity of the hypothalamus-hypophysis-adrenal axis.