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

Abstract

Summary A quantitative method for assay of free estrone, estradiol 17- β , and estradiol 17- α 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 form-amide system. The estrogens were quantitatively determined by fluorimetry, using an adaptation of the method of Bates and Cohen. Recovery of exogenous estrogens added to fetal cotyledons was approximately 83% for each of the three estrogens studied. Fetal cotyledons from 41 placentae of various stages of pregnancy were analyzed. Ten normal postpartum placentae averaged 3.5, 3.6, and 5.7 μ g/100g. of tissue, respectively, for estrone, estradiol 17- β , and estradiol 17- α , while total quantities present were, respectively, 55.9, 55.8, and 96.9 μ g. Estradiol-17 α was significantly higher than estrone or estradiol 17- β . In 31 prepartum placentae the concentration of estradiol 17- β was only slightly but consistently higher than either estrone or estradiol 17- α . The sum of the three estrogens present at 102–158, 170–212, 230–237, and 256–275 days of pregnancy was, respectively, 7.0, 11.2, 40.9, and 69.0 μ g. while similarly the concentration per 100g. of tissue was 1.4, 1.1, 2.4, and 4.0 μ g. In contrast, postpartum fetal cotyledons averaged 12.8 μ g/100g. and the total present was 208.6 μ g.