QS Study

Permissive Action of Cortisol

A small amount of cortisol must be present for a number of metabolic activities to occur although the cortisol does not produce the reaction by them. This effect is called the permissive action. Permissiveness is the situation in which a hormone cannot exert its full effects without the presence of another hormone.

Cortisol has a permissive effect on glucagon and epinephrine. Cortisol is a steroid hormone that is thought to be taken up in a target cell by simple diffusion. Permissive actions of glucocorticoids like cortisol generally occur at low concentrations. In endocrinology, permissiveness is a biochemical fact in which the existence of one hormone is necessary in order for another hormone to exert its full effects on a target cell. Hormones can cooperate in permissive, synergistic, or opposed ways.

Permissive effects include the requirement of cortisol to be present –

(1) For glucagon and catecholamines to exert their calorigenic effect.

(2) For catecholamine to exert their lipolytic effect and,

(3) For catecholamines to produce pressure response and bronchodilatation.

Thyroid hormones and glucocorticoids are examples of ‘permissive’ hormones that exert profound effects on the ability of cells to respond to other hormones, such as catecholamines.