hydroxysteroid

Hydroxysteroids are steroids that contain one or more hydroxyl (-OH) groups attached to the steroid framework. The hydroxyl substituents can be mono-, di-, or polyhydroxy, and their number and position influence properties such as polarity, solubility, and biological activity. Hydroxysteroids occur across many biological systems and include hormones, bile acids, and sterols.

In biology, many steroid hormones are hydroxysteroids, including cortisol (a glucocorticoid), testosterone (an androgen), and estradiol (an estrogen), all of which derive part of their activity from their hydroxyl groups. Bile acids such as cholic acid are also hydroxysteroids, with multiple hydroxyl groups that increase their solubility in water. Cholesterol is a basic sterol that bears a single hydroxyl group and serves as a precursor for many other hydroxysteroids through enzymatic modifications.

Biosynthesis and metabolism involve enzymatic hydroxylation of the steroid nucleus or side chain, frequently mediated by cytochrome P450 enzymes that introduce hydroxyl groups at specific positions. Hydroxysteroids can be further metabolized by hydroxysteroid dehydrogenases to form ketosteroids, and they may be conjugated (for example, with glucuronic acid or sulfate) to enhance excretion. Clinically and in research, patterns of hydroxysteroids are used as biomarkers for adrenal and gonadal function and to study steroidogenesis and metabolism.