4-Hydroxyestrone

**Semantic type:** Organic Chemical|Pharmacologic Substance

**Definition:** A metabolite formed during the catabolism of estrone by the liver through the hydroxylation of the carbon at position 4 by cytochrome P450 (CYP) family enzymes, with potential carcinogenic activity. The mechanism of action for the tumor promoting activity of 4-hydroxyestrone is not known but this metabolic product has increased estrogenic activity compared to the parent compound. Additionally, oxidation of 4-hydroxyestrone generates compounds with free radicals that are capable of removing purines from DNA, which can cause mutagenesis and can lead to tumorigenesis.

**Synonyms:** - 3,4-Dihydroxyestra-1,3,5(10)-trien-17-one - 4-HYDROXYESTRONE - 4-OHE(1) - 4-OHE1 - Estra-1,3,5(10)-trien-17-one, 3,4-dihydroxy-