18-Hydroxycorticosterone

18-Hydroxycorticosterone is a steroid hormone produced by the adrenal gland. It is a precursor molecule in the production of aldosterone, which is a vital hormone responsible for the regulation of blood pressure.

Production

18-Hydroxycorticosterone is synthesized in the zona glomerulosa of the adrenal cortex. The production of this hormone is stimulated by the adrenocorticotropic hormone (ACTH) released from the pituitary gland. The synthesis involves several enzymatic reactions, starting with the conversion of cholesterol to pregnenolone by the enzyme cholesterol desmolase. Pregnenolone is then converted to progesterone, which is further converted to 11-deoxycorticosterone by the enzymes 3β-hydroxysteroid dehydrogenase and 21-hydroxylase. Finally, 11-deoxycorticosterone is converted to 18-hydroxycorticosterone by the enzyme aldosterone synthase.

Function

18-Hydroxycorticosterone acts as a precursor in the biosynthesis of aldosterone. Aldosterone is a mineralocorticoid hormone that plays a crucial role in maintaining the body's electrolyte balance by promoting the reabsorption of sodium and excretion of potassium in the kidney. This process helps to regulate blood pressure and maintain the balance of body fluids.

Clinical significance

Abnormal levels of 18-hydroxycorticosterone can be indicative of certain medical conditions. Elevated levels may be seen in primary aldosteronism, a condition characterized by excessive production of aldosterone, leading to high blood pressure and low potassium levels. On the other hand, reduced levels of 18-hydroxycorticosterone may be associated with adrenal insufficiency, a condition where the adrenal glands do not produce sufficient steroid hormones.

See also

• Steroid hormone
• Adrenal gland
• Aldosterone
• Blood pressure
• Primary aldosteronism
• Adrenal insufficiency