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A simple adrenal gland at the left releases three streams of hormone that run rightward, one thinning to a trickle and another spilling into an overflow.

Disorders of the Adrenal Cortex

~2 min readReviewed

In this topic6

  1. The Adrenal Cortex: Structure and Hormone Families
  2. The HPA Axis and the Control of Glucocorticoid Production
  3. Steroid Hormone Synthesis in the Adrenal Cortex
  4. Aldosterone Secretion and the RAAS
  5. Cortisol Metabolism and Glucocorticoid Receptor Action
  6. Assessment of Adrenal Function

Disorders of the Adrenal Cortex

The adrenal cortex produces three families of steroid hormones: the mineralocorticoids, the glucocorticoids and the adrenal androgen precursors. Each family has its own route of synthesis, its own control system and its own actions on target tissues, and this is the organising idea of the topic: nearly every disorder of the cortex is a deficiency or an excess of one or more of these hormones.

Reading the physiology first makes those disorders predictable rather than something to memorise. The same enzymes and control loops that set the normal output are the points at which production can fall or rise, so the biology of the cortex is also the explanation of how it goes wrong.

Choose a route through the topic

Start with the first note if the gland is unfamiliar, and read onward in the order given. The sequence begins with what the cortex makes, then follows glucocorticoid control and synthesis, turns to aldosterone and its separate control system, and ends with what happens to cortisol in the body and how the whole axis is tested.

  • The Adrenal Cortex: Structure and Hormone Families sets out the three zones of the cortex, the enzyme difference that separates them, and what the mineralocorticoids, glucocorticoids and adrenal androgens do.
  • The HPA Axis and the Control of Glucocorticoid Production explains how corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) drive cortisol, how a circadian rhythm shapes it, and how negative feedback keeps it within range.
  • Steroid Hormone Synthesis in the Adrenal Cortex traces the shared pathway from ACTH and cholesterol through the CYP family of steroid-building enzymes to cortisol, aldosterone and the adrenal androgens.
  • Aldosterone Secretion and the RAAS covers the control of aldosterone by the renin-angiotensin-aldosterone system (RAAS): how the macula densa sets renin release, how angiotensin II raises aldosterone, and how potassium switches on aldosterone synthase in the zona glomerulosa.
  • Cortisol Metabolism and Glucocorticoid Receptor Action follows cortisol in the blood and in tissues: how it is carried, switched on or off by the 11β-hydroxysteroid dehydrogenase (11β-HSD) enzymes, and how it acts through the glucocorticoid receptor.
  • Assessment of Adrenal Function explains how the feedback loop is used to test the axis: dexamethasone suppression, ACTH stimulation with cosyntropin, and the insulin tolerance test.