17 beta-Estradiol and progesterone concentrations in myometrium of pregnancy and their relationships to concentrations in peripheral plasma.
17 beta-Estradiol (E2) and progesterone (P) concentrations in blood and in the myometrium of human pregnancy at term (n=33) and in a few samples (n=5) around midterm of pregnancy were determined. E2 concentration in the myometrium (per g wet wt) at midterm was lower than the concentration in the plasma (per ml) so that the myometrium to plasma (My:Pl) ratio was 0.7. Relative to plasma concentration, the myometrial E2 increased little from midterm to term so that My:Pl was only 0.2 at term. Although P concentration in the myometrium was much greater than that in the plasma at midterm, My:Pl ratio being 2.2, it was lower than that in plasma at term so that My:Pl ratio was only 0.6. A fairly good correlation between plasma steroids and the myometrial steroids was observed at midterm but was distorted at term, probably due to saturation of the tissue-binding capacity. Steroid concentrations determined on the basis of protein showed a good correlation to the values expressed on the basis of wet weight. Whereas myometrial E2 concentration was significantly influenced by the distance from placenta, P concentration was not.
D004958:Estradiol / Q000097:blood / Q000378:metabolism*; D005260:Female; D006801:Humans; D009215:Myometrium / Q000378:metabolism*; D010920:Placenta / Q000502:physiology; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011374:Progesterone / Q000097:blood / Q000378:metabolism*; D014599:Uterus / Q000378:metabolism*
D011374:Progesterone; D004958:Estradiol