60 YEARS OF POMC: from the prohormone theory to pro-opiomelanocortin and to proprotein convertases (PCSK1 to PCSK9). Therapeutic strategies for Cushing’s Syndrome: an update. A novel CYP11B2-specific imaging agent for detection of unilateral subtypes of primary aldosteronism. KeywordsĪbe T, Naruse M, Young Jr WF, Kobashi N, Doi Y, Izawa A, Akama K, Okumura Y, Ikenaga M, Kimura H, Saji H, Mukai K, Matsumoto H. Catecholamines affect many cardiovascular and metabolic processes, including increasing the heart rate, blood pressure, myocardial contractility, and cardiac conduction velocity. Adrenomedullary cells are also called chromaffin cells, because cytoplasmic granules stain brown with chromium salts, due to the oxidation of epinephrine and norepinephrine to melanin. The term catecholamine refers to substances that contain catechol and a side chain with an amino group – the catechol nucleus. These are both members of the thyroid/steroid hormone receptor superfamily of transcription factors comprising a C-terminal ligand-binding domain, a central DNA-binding domain interacting with specific DNA sequences on target genes. Both cortisol and aldosterone exert their effects following uptake of free hormone from the circulation and binding to intracellular receptors, termed the glucocorticoid and mineralocorticoid receptors. Since renin–aldosterone is one of the main regulators of blood pressure, several drugs have been developed to block this system.
Aldosterone, controlled by the renin–angiotensin system, is involved mainly in the cardiovascular homeostasis.
The most important aspect of pituitary–adrenal axis control is the negative feedback control exerted by cortisol (and so glucocorticoids), inhibiting both POMC gene transcription in the anterior pituitary and CRH mRNA synthesis and secretion in the hypothalamus. Corticotropin (adrenocorticotropic hormone, ACTH) is the principal hormone stimulating adrenal glucocorticoid biosynthesis and secretion it is produced in the anterior pituitary and derives from pro-opiomelanocortin (POMC). Three main types of steroids are produced by the adrenal cortex: glucocorticoids (cortisol), mineralocorticoids (aldosterone), and sex steroids (mainly androgens).
Steroidogenesis is the complex pathway used to transform cholesterol in steroid hormones. The adrenal glands (also known as suprarenal glands) are endocrine glands, found above the kidneys, which produce a variety of intracellular hormones.
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