title: Low plasma levels of 2-hydroxyestrone are consistent with its rapid metabolic clearance.
abstract: Published plasma levels of the catechol estrogen 2-hydroxyestrone (2-OHE1) are comparable to those of estrone and estradiol. In light of the very high (40,000 L/d) metabolic clearance rate of 2-OHE1, these concentrations imply unreasonable production rates. We therefore re-examined plasma 2-OHE1 levels using a modified radioimmunoassay procedure. Plasma samples are extracted with ethyl acetate and passed over a short column of LH-20 Sephadex before equilibration with an antiserum directed against a 2-hydroxyestrone-17-(O-carboxymethyl)oxime-bovine serum albumin conjugate. Plasma 2-OHE1 concentrations are indistinguishable from blank (< 15 pg/ml) in men and non-pregnant women, but rise to approximately 200 pg/ml during pregnancy. These values for 2-OHE1 levels are consistent with the rapid metabolic clearance of this catechol estrogen.
mesh_terms: D000293:Adolescent; D000328:Adult; D003429:Cross Reactions; D004970:Estrone / Q000031:analogs & derivatives*; D005260:Female; D006801:Humans; D006894:Hydroxyestrones / Q000097:blood* / Q000276:immunology; D008297:Male; D008598:Menstruation; D008657:Metabolic Clearance Rate; D011247:Pregnancy; D011863:Radioimmunoassay; D013997:Time Factors
chemical_list: D006894:Hydroxyestrones; D004970:Estrone