Immobilization Stress Induced Changes in Adrenocortical and Medullary Cyclic AMP Content in the Rat

Abstract

The levels of adrenal cyclic AMP in adrenal cortex and medulla have been examined during immobilization stress under varying conditions. After 30 min of immobilization, there was a highly significant rise in whole adrenal cyclic AMP, returning to base line levels after 150 min. Theophylline pretreatment shifted the maximal cyclic AMP increase after immobilization to 10 min, with return to almost base line values at 30 min. Hypophysectomy blocked the rise in adrenal cyclic AMP and, in fact, there was a small but significant decrease after 10 or 30 min of immobilization. Denervation of the adrenal gland did not alter the level of cyclic AMP in unstressed animals but reduced the elevation of cyclic AMP to about 50% of the response observed in the intact adrenals of stressed animals. There was no increase in cyclic AMP in the adrenal medulla after stress although the medullary component of cyclic AMP was 50% of the total. There was a highly significant cortical increase in cyclic AMP after immobilization. Finally, a significant increase was observed in adrenocortical cyclic AMP in denervated adrenals of stressed animals but not in the medulla. Thus, either the splanchnic nerve or the adrenal medulla via the nerve may be releasing a factor which takes part in the regulation of adrenocortical cyclic AMP. (Endocrinology88: 338, 1971)