2-Hydroxyestrone

2-Hydroxyestrone (2-OHE1) is one of the major metabolites of estrogen, a primary female sex hormone. It is produced in the body through the process of hydroxylation, specifically at the 2-position of the estrone molecule, hence its name.

Metabolism

The metabolism of 2-Hydroxyestrone occurs in the liver through the action of cytochrome P450 enzymes, particularly CYP1A2 and CYP3A4. These enzymes add a hydroxyl group to the 2-position of the estrone molecule, converting it into 2-Hydroxyestrone. This metabolite is then further metabolized by sulfotransferase enzymes, which add a sulfate group, and glucuronosyltransferase enzymes, which add a glucuronide group, to make it more water-soluble and easier for the body to excrete.

Biological Activity

2-Hydroxyestrone is considered a "good" estrogen metabolite due to its weak estrogenic activity. It binds weakly to estrogen receptors, thus exerting less estrogenic effects compared to other estrogen metabolites. This property is believed to be protective against certain estrogen-sensitive cancers, such as breast cancer and endometrial cancer.

Clinical Significance

The ratio of 2-Hydroxyestrone to another estrogen metabolite, 16α-Hydroxyestrone, is often used as a biomarker for breast cancer risk. A higher ratio is associated with a lower risk of breast cancer. This ratio can be influenced by diet and lifestyle factors, and is a focus of research in the field of nutritional epidemiology.

See Also

• Estrogen
• Estrone
• 16α-Hydroxyestrone
• Cytochrome P450
• Breast cancer
• Endometrial cancer