PubMed1975
Plasma progesterone, 17alpha-OH-progesterone, estrone, 17beta-estradiol and estriol in human normal pregnancy, labor and the puerperium were measured simultaneously with radioimmunoassay or competitive protein binding assay. The steroids were extracted from the sample plasma with diethyl either, and were separated through two steps of sephadex LH-20 microcolumn chromatography prior to the assays. From the beginning to the 25th week of pregnancy, a gradual rise in the levels of plasma progesterone was noted, followed by a steep increase toward term with a level of 150-250 ng/ml at the end of gestation. The levels of 17alpha-OH-progesterone during the 7th or 8th week of pregnancy were 2-3 ng/ml, which was above the normal range in the luteal phase, followed by a gradual decrease during 15-25 weeks of gestation. Thereafter, an increase toward term was seen with a mean level of 6-10 ng/ml in the 40th week. From the beginning to the end of pregnancy, plasma levels of estrone, 17beta-estradiol, and estriol increased from less than 0.5 ng/ml to 2-4 ng/ml, from 1-2.5 ng/ml to 6-10 ng/ml, and from less than 1 ng/ml to 6-10 ng/ml, respectively. The disappearance of steroids from maternal peripheral blood in the puerperium was rapid. The half time of progesterone, 17alpha-OH-progesterone, estrone, 17beta-estradiol, and estriol were 72 min, 68 min, 27 min, 27 min, and 48 min, respectively. Analysis of the interrelation between several kinds of steroids of pregnancy, labor, and the puerperium with simultaneous microassays will contribute to the clarification of some important physiological and pathological aspects of feto-placental-maternal functions and steroidogenic functions of the corpus luteum in pregnancy.