title: A direct time-resolved fluoroimmunoassay (TR-FIA) for measuring plasma estradiol-17beta concentrations in cattle.
abstract: A direct Time-Resolved Fluoroimmunoassay (TR-FIA) system for measuring estradiol-17beta (E(2)) in bovine plasma was developed and evaluated. A 100 microl sample of bovine plasma was used for a TR-FIA without prior extraction and purification. The dose-response curves of reference standards ranged from 0.0625 to 10 pg/well. The minimum detectable concentration of this assay system was 0.625 pg/ml, and 19 pg/ml of E(2) caused a 50% reduction of maximum binding. The intra- and inter-assay coefficients of variation were 10.2 and 17.4%, respectively. The plasma E(2) concentrations measured by direct TR-FIA correlated closely with those measured after extraction (r=0.939). The results in the present study indicate that the TR-FIA reagent for E(2), designed for human research can also be utilized, with some modification, for direct assaying in bovine plasma. This assay type seems to fulfill the requirements for safety, sensitivity, specificity, reproducibility and practical convenience.
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba, Ibaraki, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Takahashi
authors.forename: Sanae
authors.initials: S
authors.lastname: Hamanaka
authors.forename: Kei
authors.initials: K
authors.lastname: Imai
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Hashizume
mesh_terms: D000818:Animals; D002417:Cattle / Q000097:blood*; D004958:Estradiol / Q000097:blood*; D015200:Fluoroimmunoassay / Q000379:methods; D011374:Progesterone / Q000097:blood
chemical_list: D011374:Progesterone; D004958:Estradiol