A metabolite of Estradiol
ChEBI: A 2-hydroxy steroid that consists of 17beta-estradiol having an additional hydroxy group at position 2.
2-hydroxyestradiol is an angiogenesis inhibitor via the hif-1a pathway.hif-1a, a basic helix-loop-helix pas domain containing protein, is reported as the master transcriptional regulator of cellular and developmental response to hypoxia.
in vitro evidences suggested that most of the cellular effects of 2-hydroxyestradiol were mediated by 2-methoxyestradiol, a metabolite of 2-hydroxyestradiol as an anti-cancer agent acting as an angiogenesis inhibitor via the hif-1a pathway. inhibition of catechol-o-methyltransferase (comt), the enzyme methylating 2-hydroxyestradiol to 2-methoxyestradiol, blocked the ability of 2-hydroxyestradiol to inhibit growth of vascular smooth muscle cells, cardiac fibroblasts, as well as renal mesangial cells. moreover, 2-hydroxyestradiol could inhibit vascular smooth muscle cell growth in cells obtained from wild-type mice but not in cells cultured from comt knockout mice. in contrast to 2ohe, treatment of vascular smooth muscle cells with 2-methoxyestradiol inhibited serum-induced growth of cells from both wild-type and comtknockout mice [1].
animal study showed that after administration of 2-hydroxyestradiol, plasma levels of 2-hydroxyestradiol declined extremely rapidly. concomitant with the disappearance of 2-hydroxyestradiol, 2-methoxyestradiol occurred and then declined. after administration of 2-methoxyestradiol, plasma levels of 2meoe declined with a plasma cl of 50 ml min(-1) kg(-1). we could not detect 2-hydroxyestradiol in plasma from rats receiving 2-methoxyestradiol. thus, the authors conclude that the conversion of 2-hydroxyestradiol to 2-methoxyestradiol was so efficient, and the administration of 2-hydroxyestradiol is bioequivalent to administration of 2-methoxyestradiol itself [1].
[1] zacharia, l. c.,piché, c.a.,fielding, r.m., et al. 2-hydroxyestradiol is a prodrug of 2-methoxyestradiol. journal of pharmacology and experimental therapeutics 309(3), 1093-1097 (2004).
