11β-Hydroxyprogesterone

11β-Hydroxyprogesterone (11β-OHP) is a steroid hormone that is produced in the adrenal glands as an intermediate in the biosynthesis of cortisol. It is a glucocorticoid and has a similar structure to progesterone, but with an additional hydroxy group at the 11-beta position.

Biosynthesis

The biosynthesis of 11β-Hydroxyprogesterone begins with the conversion of cholesterol to pregnenolone by the enzyme cholesterol side-chain cleavage enzyme (P450scc). Pregnenolone is then converted to progesterone by the enzyme 3β-hydroxysteroid dehydrogenase (3β-HSD). Progesterone is converted to 11β-Hydroxyprogesterone by the enzyme 11β-hydroxylase (CYP11B1), which is located in the mitochondria of the adrenal cortex.

Function

11β-Hydroxyprogesterone has a similar function to progesterone, but with additional glucocorticoid activity. It is involved in the regulation of the immune system, inflammation, blood pressure, and metabolism. It also plays a role in the stress response, as it is a precursor to cortisol, the body's main stress hormone.

Clinical significance

Elevated levels of 11β-Hydroxyprogesterone can be a marker for congenital adrenal hyperplasia (CAH), a group of inherited disorders of the adrenal glands. CAH is often caused by mutations in the CYP11B1 gene, which leads to a deficiency in 11β-hydroxylase and an accumulation of 11β-Hydroxyprogesterone. This can result in symptoms such as virilization, hirsutism, and hypertension.

See also

• Cortisol
• Progesterone
• Congenital adrenal hyperplasia
• 11β-hydroxylase