The demonstration of the remarkable biological effects of the adrenal cortical hormone, hydrocortisone, constitutes an important advance in medical science in the past two decades. This hormone and its derivatives have since been widely employed in both therapeutic and investigative medicine. It has been shown that the rate of secretion of hydrocortisone is regulated by the amount of ACTH, its trophic hormone, that is secreted by the anterior pituitary. The blood level of hydrocortisone, which results from ACTH stimulation, acts in turn to suppress further production of ACTH.
More recently, another steroid, aldosterone, has been found to be produced by the adrenal cortex. This hormone is secreted in relatively minute amounts. It is the most powerful of all the naturally occurring steroids in its ability to promote renal retention of sodium and excretion of potassium. Aldosterone has very little anti-inflammatory activity, and, unlike hydrocortisone, its rate of secretion is not