Aldosterone: Synthesis and regulation.

Aldosterone, the principal mineralocorticoid, is exclusively synthesized in the glomerular zone of the adrenal cortex. Its primary function is to maintain water and electrolyte balance and regulate blood pressure. The synthesis of aldosterone begins with the transport of cholesterol to the mitochondria, a process that is mediated by the StAR protein. This is followed by a sequence of reactions that are catalyzed by specific enzymes. CYP11A1, 3β-HSD2, CYP21A2, and finally CYP11B2. The regulation of its production is classified as acute, dependent on the rapid activation of StAR, and chronic, involving the sustained transcription of CYP11B2.The regulation of this process is influenced by three physiological stimuli: angiotensin II, which is produced through the renin-angiotensin system, increased extracellular potassium, and ACTH. Angiotensin II and potassium have been shown to activate intracellular signals that increase cytoplasmic calcium, thereby promoting both StAR activation and CYP11B2 expression. ACTH stimulates synthesis via the cAMP/PKA pathway, although its effect is brief.Other modulators of significance include natriuretic peptides, dopamine, serotonin, inflammatory cytokines, microRNAs, and sex hormones such as testosterone and progesterone. Comprehension of these mechanisms is imperative for the effective management of pathologies, including primary hyperaldosteronism, a condition that is associated with secondary hypertension and progressive organ damage.