The production and secretion of adrenocortical steroid in man.

In the human adrenal cortex the fascicular and reticular zones increase and decrease in width. Whe the individual is under stress the reticular zone appears to grow at the expense of the fascicular zone. The combined zones produce cortisol which cannot be synthesized in the glomular cells as they do not possess the steroid alpha-hydroxylase. The zones also produce dehydroepiandrosterone (DHA) sulphate (a quantitatively important adrenal secretory product in man) and possibly testosterone and adrenal estrogens. The fascicular cells contain relatively large amounts of lipids including cholesterol esters. There is evidence that cholesterol is a precursor of steroid hormones in the adrenal cortex. It is not know however whether prostaglandins are produced by the adrenal gland although such an occurrence may result in the relaxation of the longitudinal muscle bundles and thus allow increases in blood flow. Although the concentration of prostaglandin substances in the adrenal cortex as a whole may be rather low it is possible that they may be concentrated in the cells lying in the border between fascicular and reticular zones. Further research should be done on the distribution of prostaglandis in the adrenal cortex and the effect of ACTH on it.