17α-Hydroxyprogesterone

17α-Hydroxyprogesterone (17-OHP) is a steroid hormone produced in the adrenal glands and gonads. It is an intermediate in the biosynthesis of glucocorticoids and gonadal steroids, and is also produced in the placenta during pregnancy.

Structure and Synthesis

17α-Hydroxyprogesterone is a C21 steroid, meaning it has 21 carbon atoms. It is synthesized from progesterone via the enzyme 17α-hydroxylase, a member of the cytochrome P450 family. This reaction also requires the coenzyme NADPH and molecular oxygen.

Function

17α-Hydroxyprogesterone is a precursor in the production of other steroid hormones. It is converted to 11-Deoxycortisol by the enzyme 21-hydroxylase, which is then converted to cortisol by 11β-hydroxylase. It can also be converted to androstenedione via the 17,20 lyase activity of CYP17A1.

Clinical Significance

Elevated levels of 17α-Hydroxyprogesterone can be indicative of congenital adrenal hyperplasia (CAH), a group of inherited disorders affecting the adrenal glands. This is most commonly due to a deficiency in 21-hydroxylase. Measurement of 17α-Hydroxyprogesterone levels is used in the newborn screening for CAH.

In addition, 17α-Hydroxyprogesterone has been used in the treatment of preterm labor. However, its effectiveness for this purpose is unclear, and it is not currently recommended as a standard treatment.

See Also

• Steroid hormone
• Congenital adrenal hyperplasia
• Preterm labor