Quantitative Determination of Free Estrone, Estradiol 17-β, and Estradiol 17-α in Bovine Fetal Cotyledons

Abstract

A quantitative method for assay of free estrone, estradiol 17-/], and estradiol l?-a in bovine fetal cotyledons is reported. Ethyl-acetate was used for initial extraction. The extract was partially purified by partitioning between toluene and 5% NaOH, followed by partitioning between the neutralized aqueous fraction and benzene. The estrogens were separated by paper chromatography, using the benzene-Skellysolve-B 1:1 formamide system. The estrogens were quantitatively determined by fluorimetry, using an adaptation of the method of Bates and Cohen. Recovet~y of exogenous estrogens added to fetal cotyledons was approximately 83% for each of the three estrogens studied.