Adrenal Steroids, Adrenocorticotropic Hormone, and Plasma Renin Activity

Abstract

The adrenal cortex is responsible for the production of three categories of steroid hormones. Mineralocorticoids (primarily aldosterone) are synthesized in the zona glomerulosa and regulate electrolyte balance, blood pressure, and intravascular volume. Glucocorticoids (primarily cortisol) are synthesized in the zona fasciculata and have a wide variety of functions that include the response to stress. Adrenal androgens, synthesized in the zona reticularis, are responsible in part for the development of secondary sexual characteristics. It is important for primary care providers to have an understanding of the pathways of steroid biosynthesis because testing of these hormones is essential in the diagnosis of different forms of congenital adrenal hyperplasia (CAH), other causes of adrenal insufficiency, and Cushing’s syndrome. What follows is a brief review of diagnostic testing for common adrenal diseases and enzymatic defects.