Simultaneous Measurement of Plasma Progesterone, 17-Hydroxyprogesterone and Estradiol-17B by Radioimmunoassay

A rapid 5 hour radioimmunoassay of progesterone and oestradiol in human plasma

A rapid 5 h radioimmunoassay method for the determination of progesterone and oestradiol in the plasma of non-pregnant women is described. Due to the high specificity of the antisera used, it is possible to perform the radioimmunoassay directly on the ether extracts of plasma, without employing chromatographic purification of the steroids. Evidence is presented indicating that the rapid assay is almost as reliable as the previously described radioimmunoassay method which involves chromatography. The within-assay and between-assay coefficients of variation in the progesterone assay were 7-74 and 14-9 and in the oestradiol assay 7-36 and 18-1 respectively. Comparisons between increasing doses of authentic hormone and endogenous hormone extracted from plasma indicated no deviation from parallelism. Progesterone and oestradiol were assayed in 300 plasma samples by the rapid method and by the method involving chromatography. The slopes obtained by a regression analysis were close to unity for both progesterone and oestradiol (1-04 and 1-06, respectively), the y-intercepts were - 0-21 and 0-16 and the correlation coefficients 0-98 and 0-88, respectively. When the data obtained by both techniques in fourteen menstrual cycles were compared, the results were practically identical. In ten repeated studies conducted by four investigators it was shown that two workers can complete the assay of both progesterone and oestradiol in twenty-five plasma samples in duplicates with 5 h. The same time required for the assay of either progesterone or oestradiol in twenty-five duplicates by one worker.

Influence of prostaglandin F autoantibodies on the estrous cycle of the guinea pig

Adult female guinea pigs were actively immunized with prostaglandin F-2alpha conjugated to bovine serum albumin (BSA). Control animals, immunized against BSA continued to cycle normally, while the animals immunized against prostaglandin F-2alpha stopped cycling after one to three normal cycles. Laparotomy at 30 days after the last estrus revealed no recently formed corpora lutea. During the remaining 70 days of observation the antibody titer increased to 1:700, accompanied by increasing total serum estrogens (136 pg/ml at day 100) and a slow decline in circulating progesterone levels (0.6 ng/ml at day 100). The ovaries at day 100 contained degenerated corpora lutea and luteinized follicles. The suppression of the estrous cycle in the present experiments was interpreted as resulting from prolongation of luteal function as well as from inhibition of ovulation.