title: Rapid metabolic clearance of the catechol estrogen 2-hydroxyestrone.
abstract: The plasma metabolic clearance rate (MCRp) of 2-hydroxyestrone was measured in normal young adults by two methods: infusion of unlabeled 2-OHE1 to equilibrium with radioimmunoassay of plasma 2-OHE1 levels, and infusion of [3H]2-OHE1 to equilibrium with measurement of chromatographically purified plasma [3H]2-OHE1. MCR's were 40--70,000 L/day and 15--50,000 L/day, respectively. This is the highest known MCR for a naturally occurring steroid. The only measurable plasma metabolite of [3H]2-OHE1 co-migrated with 2-methoxyestrone. When [3H]2-OHE1 was incubated with blood samples in vitro, [3H] xi-methoxyestrone was rapidly formed. Since this MCR is higher than cardiac output, clearance must occur primarily in the blood compartment, probably largely by the action of erythrocyte catechol-0-methyltransferase.
mesh_terms: D000328:Adult; D004970:Estrone / Q000031:analogs & derivatives* / Q000097:blood; D006801:Humans; D006894:Hydroxyestrones / Q000097:blood*; D007700:Kinetics; D008657:Metabolic Clearance Rate; D011863:Radioimmunoassay
chemical_list: D006894:Hydroxyestrones; D004970:Estrone; C024980:2-hydroxyestrone