[Endocrinology of aldosterone]

Abstract

Aldosterone is the major mineralocorticoid hormone produced by the zona glomerulosa of the adrenal cortex. Aldosterone secretion is mainly regulated by the renin-angiotensin system, and to a minor extent by serum concentration of potassium, sodium, adrenocorticotropic hormone. and dopamine. This hormone, as well as other adrenal corticosteroids, exert many of its physiological actions through modulation of gene expression. It binds cytosolic receptors that translocate to the nucleus in a ligand-dependent manner and induces transcription of specific genes that encode for proteins involved in the cardiovascular homeostasis. Such proteins act regulating vascular tone, sympathetic nervous system activity, and hydroelectrolyte transport in epithelial tissues. Classical aldosterone target tissues are kidney, colon, sweat and salivary glands. Apart from the genomic effects, which imply a direct action on DNA, rapid non-genomic actions of aldosterone have been recently described in both epithelial and non-epithelial tissues and structures such as heart, vasculature, and kidney. At these sites aldosterone contributes to the development of cardiac fibrosis, myocardial hypertrophy, heart failure and arrhythmias; other deleterious effects exerted by aldosterone include vascular remodeling, endothelial dysfunction, perivascular inflammation, renal fibrosis, and progressive renal failure. Finally, recent evidence has focused on the possible implications of aldosterone excess on metabolic alterations, as described in patients with primary aldosteronism. On these premises lies the pathogenetic role of aldosterone in the development of cardiovascular diseases and the rationale for the use of mineralocorticoid receptor antagonists in the primary and secondary prevention of the complications related to these diseases.