Unconjugated steroids in the fallopian tube and peripheral blood during the normal menstrual cycle.

Daily plasma samples were obtained from 22 high-parity normal women beginning on day 9 of the menstrual cycle. At varying times in the cycle, salpingectomy was performed and the excised tube was divided into isthmic, ampullary, and fimbrial segments. Simultaneous determinations of 17 beta-estradiol (E2), estrone (E1), and progesterone (P) in plasma and tubal tissue were carried out by specific radioimmunoassay. The highest ratio for E2 tissue to E2 plasma was seen at the time of the E2 peak. The E2 concentrations in the three anatomical segments of the fallopian tube during the late proliferative phase were significantly (P less than 0.05) higher than those during the early proliferative and late postovulatory periods. A significant (P less than 0.05) increase in P concentration was seen in both plasma and oviductal tissue after ovulation. The tubal tissue to plasma ratio had a tendency to decrease during the secretory phase, indicating a limited uptake of P during the secretory phase. The plasma levels of esterone were almost constant during the normal menstrual cycle. The highest concentration of E1 was seen in the fimbriae (254 +/- 71 pg/gm and ampulla (326 +/- 75 pg/gm during the early secretory phase of the cycle. The possible role of E1 during this crucial time of oviductal physiology is considered.