Abstract
The authors presented a simple and effective radioimmunoassay method for bovine plasma androstenedione (4-A'dione), and an assay result of it during gestation period, around parturition, and in postpartum was reported.
The bovine plasma, 3.0 ml was extracted with methylene dichloride and was subjected to a Sephadex LH-20 micro-column for the separation. The effluent containing 4-A'dione was evaporated and was incubated with an anti-DHEA-3-O•CO-BSA mixture, consisted of 4-A'dione-1-2-3H, pepsin-treated human immune serum globulin, bovine albumin and the antibody. For separation of free from bound 4-A'dione, ammonium sulphate was applied. Each of the accuracy, precision, sensitivity, and specificity test for this assay method revealed quite satisfactory result. This type of method, by which certain two, three steroids can be assayed at one time by a single antiserum may be recommended for clinical diagnostic laboratory use; the authors reported previously1) such an assay method for the three estrogens in bovine plasma by using an estrone-17β-BSA antiserum.
The plasma 4-A'dione from the time of conception through to the 210th day of pregnancy showed about 100 to 200 pg/ml level, rather in simple pattern, but after the time the level elevated gradually and the maximum levels ranging from 900 to 1, 600 pg/ml were recorded near term. In postpartum, very low levels about 100 or less pg/ml were recorded on the day or the next day of parturition and this state almost continued for the following 6 weeks. The increase of the plasma 4-A'dione which occured in the last trimester seemed to precede the general increase of the plasma estrogens in the late gestation period. This finding and also the assay result of 4-A'dione and estrogens in the plasmas in the feto-placental unit, which had been collected by Caesarian section might suggest that on the 198th and 244th day of pregnancy, secretion of 4-A'dione depended mostly upon the maternal adrenal, though for further reliable elucidations, apparently more of the additional works must be requested.
