ACTH secretion, in turn, is inhibited by increasing levels of cortisol. This process is termed negative feedback regulation. The system is fine-tuned, therefore, Trough a feedback control mechanism that is similar to those of many other hormone systems, including estrogen and gonadotropins in the reproductive system. Glucocorticoids, like other steroid hormones, exert their biologic effects by binding to specific intracellular receptors. I and type II receptors.
Several factors influence glucocorticoid actions on a given tissue.
These include the type and amount of steroid available, and the number of glucocorticoid receptors. The importance and function of glucocorticoids are made clear by examining information from states of deficiency and excess. Cushing's syndrome and adrenal insufficiency are diseases of too much and too little glucocorticoid, respectively. Ectopic secretion of ACTH is not responsive to the normally operative negative feedback by glucocorticoids. A shorter version of the manuscript is in press, in the New England Journal of Medicine.