16-Hydroxydehydroepiandrosterone sulfate

16-Hydroxydehydroepiandrosterone sulfate (16-OH-DHEAS) is a steroid metabolite of dehydroepiandrosterone (DHEA) that is produced in the adrenal gland. It is a sulfate conjugate of 16α-hydroxy-DHEA, which is formed by the action of hydroxysteroid sulfotransferase enzymes in the liver and adrenal cortex.

Structure and Properties

16-OH-DHEAS is a hydroxylated and sulfated derivative of DHEA, a precursor to sex steroids. It has a molecular weight of 402.49 g/mol and a chemical formula of C19H28O8S. The hydroxylation at the 16α position and the addition of a sulfate group increase the water solubility of the molecule, facilitating its excretion in the urine.

Biosynthesis and Metabolism

The biosynthesis of 16-OH-DHEAS begins with the conversion of cholesterol to pregnenolone in the mitochondria of adrenal cells. Pregnenolone is then converted to DHEA by the sequential action of 17α-hydroxylase and 17,20-lyase. The 16α-hydroxylation of DHEA is catalyzed by cytochrome P450 enzymes, and the resulting 16α-hydroxy-DHEA is sulfated by hydroxysteroid sulfotransferases to form 16-OH-DHEAS.

16-OH-DHEAS is metabolized primarily in the liver, where it can be desulfated and further metabolized to other steroid hormones, or excreted in the urine.

Biological Activity

16-OH-DHEAS has been found to have weak androgenic and estrogenic activity, similar to other DHEA metabolites. However, its physiological role is not fully understood. It has been suggested that 16-OH-DHEAS may serve as a reservoir for the production of other active steroids, or that it may have unique biological effects of its own.

Clinical Significance

Elevated levels of 16-OH-DHEAS in the blood or urine can be indicative of an adrenal disorder, such as adrenal hyperplasia or an adrenal tumor. Measurement of 16-OH-DHEAS levels can therefore be useful in the diagnosis and monitoring of these conditions.