Radioimmunoassay of 2-hydroxyestrone in plasma during the estrous cycle of the rat: interrelationships with estradiol, progesterone, and the gonadotropins.
A RIA for 2-hydroxyestrone (2-OHE1) in rat plasma has been developed. The assay employs an antiserum that is specific for catechol estrogens. Specificity is further ensured by purification of plasma extracts on Sephadex LH-20 columns before RIA. Blood was collected at 0 C in the presence of ascorbic acid to prevent oxidation. Under these conditions, the conversion of 2-OHE1 to methylated derivatives was found to be negligible. Plasma 2-OHE1, LH, FSH, PRL, estradiol, and progesterone were measured at 3-h intervals throughout the 4-day estrous cycle of the rat. The 2-OHE1 concentration varied from undetectable to 11 pg/ml plasma. No clearly defined relationship with the other hormones analyzed was observed. Thus, it is unlikely that changes in circulating 2-OHE1 levels are involved in the regulation of the gonadotropin surge and ovulation.
D000818:Animals; D004958:Estradiol / Q000097:blood*; D004970:Estrone / Q000031:analogs & derivatives*; D004971:Estrus; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D006894:Hydroxyestrones / Q000097:blood*; D007986:Luteinizing Hormone / Q000097:blood*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood*; D011388:Prolactin / Q000097:blood; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D011919:Rats, Inbred Strains
D006894:Hydroxyestrones; D004970:Estrone; D011374:Progesterone; D004958:Estradiol; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; C024980:2-hydroxyestrone