3hidroxiszteroid

3-hydroxy steroids are steroids bearing a hydroxyl group at the third carbon (C3) of the steroid nucleus. This feature marks a broad subset of steroids that often serve as metabolic intermediates in steroidogenesis and as important precursors to other hormones. In humans, common examples include cholesterol, pregnenolone, and dehydroepiandrosterone (DHEA). Cholesterol is the principal 3-hydroxy steroid and the starting point for the synthesis of all steroid hormones. Pregnenolone is formed from cholesterol by the mitochondrial enzyme CYP11A1 and acts as a key precursor to glucocorticoids, mineralocorticoids, and sex steroids. Through the action of 3β-hydroxysteroid dehydrogenase/isomerase (HSD3B), 3-hydroxy steroids can be converted to 3-keto steroids such as progesterone, enabling downstream enzymatic steps in hormone biosynthesis.

These steroids occur in tissues such as the adrenal cortex, gonads, and brain, where they function both as metabolic intermediates and, in some cases, as independent signaling molecules. As precursors, they influence the production of corticosteroids, androgens, and estrogens; some 3-hydroxy steroids also exhibit neuroactive properties beyond their roles as hormone precursors.

In research and medicine, 3-hydroxy steroids are studied for their roles in development, metabolism, and brain function. Pregnenolone, in particular, is occasionally used in limited clinical or research contexts as a supplement or experimental compound. Overall, they form a foundational class within steroid biochemistry, linking cholesterol to the diverse array of steroid hormones.