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

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Abstract
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. Recovery of exogenous estrogens added to fetal cotyledons was approximately 83% for each of the 3 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 [mu]g/100 g of tissue, respectively, for estrone, estradiol 17-[beta], and estradiol 17-a, while total quantities present were, respectively, 55.9, 55.8, and 96.9[mu]g. Estradiol-17a was significantly higher than estrone or estradiol 17-[beta]. In 31 prepartum placentae the concentration of estradiol 17-[beta] was only slightly but consistently higher than either estrone or estradiol 17-[alpha]. The sum of the 3 estrogens present at 102-158, 170-212, 230-237, and 256-275 days of pregnancy was, respectively, 7.0, 11.2, 40.9, and 69.0ug while similarly the concentration per 100 g of tissue was 1.4, 1.1, 2.4, and 4.0[mu]g. In contrast, postpartum fetal cotyledons averaged 12.8[mu]g/100 g and the total present was 208.6[mu]g.