Progesterone (17-Hydroxy)

17-alpha-hydroxy-progesterone is a twenty-one carbon steroid produced primarily in the adrenals, and some are found in the ovaries, testes and placenta. It serves as a biosynthetic precursor to cortisol. Its measurement is of value in the diagnosis and management of congenital adrenal hyperplasia, hirsutism and infertility. In the most common form of congenital adrenal hyperplasia, deficiency of the enzyme 21-hydroxylase blocks normal synthesis of cortisol, leading to a compensatory increase of ACTH secretion. This results in adrenal hyperplasia with increased levels of 17-alpha-hydroxy-progesterone, DHEA and other adrenal steriods. Untreated congenital adrenal hyperplasia in newborns is usually associated with low cortisol and markedly elevated 17-alpha-hydroxy-progesterone levels ranging from 10 to 400 times the upper limit of normal. Some late-onset congenital adrenal hyperplasia may present modestly elevated basal 17-alpha-hydroxy-progesterone levels and an ACTH stimulation may be required to differentiate it from the polycystic ovary syndrome.