2OHE1

2OHE1, or 2-hydroxyestrone, is a metabolite of the natural estrogen estrone formed by hydroxylation at the C2 position of the estrogen molecule. It is produced mainly in the liver through cytochrome P450–mediated pathways, with enzymes such as CYP1A1 and CYP1A2 contributing, and to a lesser extent by other P450s like CYP1B1. After formation, 2-hydroxyestrone is rapidly conjugated (for example to glucuronide or sulfate forms) and excreted in urine and bile.

In the body, 2-hydroxyestrone is considered to have markedly lower estrogenic activity than estrone and generally shows reduced affinity for estrogen receptors ERα and ERβ. Some studies suggest potential anti-estrogenic effects in certain cellular contexts, but its activity is context-dependent and less potent than that of parent estrogens.

Clinical and research relevance of 2OHE1 centers on its role in estrogen metabolism. The ratio of 2-hydroxyestrone to 16α-hydroxyestrone (16α-OHE1) has been investigated as a biomarker of estrogen metabolism and as a potential indicator of breast cancer risk, though findings are inconsistent and there is no consensus on its predictive value or clinical use.

Detection and measurement of 2OHE1 are typically performed in urine or plasma using analytical methods such as LC-MS. Dietary and lifestyle factors can influence estrogen-metabolizing enzyme activity, with some evidence that cruciferous vegetables may shift metabolism toward the 2-hydroxylation pathway.

Chemical information: 2-hydroxyestrone has the molecular formula C18H22O3 and belongs to the class of phenolic estrogens.