[Hypophyseal-adrenal cortex system function after administration supraphysiological doses of corticosteroids on...

Injection of hydrocortisone in supraphysiological doses (10 mg twice a day for 2 days) to rabbits produced long-term disorders in hypophyseal-adrenocortical function. The time-course of changes in the blood corticosteroid basal level, the adrenocortical reactivity to ACTH and the ability of the hypophyseal-adrenocortical system to respond to immobilization were investigated. The three periods were detected after hydrocortisone injection, characterizing hypophyseal-adrenocortical function. During the 1st period, the adrenocortical reactivity was inhibited and the response to the stressor was absent in the presence of a normal blood corticosteroid basal content. Within the 2nd period, the corticosteroid basal level was higher than that of the control animals, the adrenocortical reactivity to ACTH arose, but the response to the stressor was absent. At the 3d period all the three parameters under study began returning to normal.