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Quantitative Determination of Free Estrone, Estradiol 17-ß, and Estradiol 17- in Bovine Fetal Cotyledons¹

Department of Dairy Science, Washington State University, Pullman

ABSTRACT

A quantitative method for assay of free estrone, estradiol 17-ß, and estradiol 17- 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 µg/100 g. of tissue, respectively, for estrone, estradiol 17-ß, and estradiol 17-, while total quantities present were, respectively, 55.9, 55.8, and 96.9 µg. Estradiol-17 was significantly higher than estrone or estradiol 17-ß. In 31 prepartum placentae the concentration of estradiol 17-ß was only slightly but consistently higher than either estrone or estradiol 17-. 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 µg. while similarly the concentration per 100 g. of tissue was 1.4, 1.1, 2.4, and 4.0 µg. In contrast, postpartum fetal cotyledons averaged 12.8 µg/100 g. and the total present was 208.6 µg.

¹ Scientific Paper No. 1886 Washington Agricultural Experiment Stations. Work was conducted under Project No. 1359-195. This investigation was supported in part by funds for biological and medical research by the State of Washington, Initiative Measure No. 171.

² Present address: McArdle Memorial Laboratory, University of Wisconsin, Madison, Wisconsin.