Topic overview

Start with the big picture

The cortex’s zona glomerulosa, fasciculata, and reticularis produce aldosterone, cortisol, and androgens, respectively. All cortical steroid synthesis begins with cholesterol conversion to pregnenolone, a rate-limiting step involving StAR and CYP11A1; the glomerulosa’s lack of 17α-hydroxylase helps explain its distinct output. Secretion is regulated differently: ACTH stimulates cortisol and androgen production, while aldosterone is mainly controlled by the renin–angiotensin system and potassium. The lesson also introduces hormone transport, receptor-mediated effects, feedback, and metabolism. These mechanisms help explain cortisol’s metabolic and anti-inflammatory actions, aldosterone’s effects on renal electrolyte handling and volume, and the physiological contribution of adrenal androgens. Clinical connections include features associated with cortisol excess and deficiency.