[Cyclic changes in sex steroids, prostaglandins and oxytocin receptors of normal fallopian tube throughout the menstrual cycle].

It is considered that the physiology of the human fallopian tube may be dependent on endocrine factors, especially their changes during the menstrual cycle in the fractionated fallopian tissues. In the present study, the dynamics of sex steroids (estradiol, E and progesterone, P), prostaglandins (PGs) and oxytocin (OT) binding to each receptor (R) in the ampullary and isthmic regions were analyzed simultaneously throughout the menstrual cycle. The number of binding sites (NBS) for nuclear ER (ERN) levels was always greater in the ampulla than in the isthmus, while that for nuclear PR (PRN) was almost the same. The NBS of both E-, and PRN reached the highest levels during the late proliferative to ovulatory phase. The NBS of both PGE2-, and PGF2 alpha-R in the isthmus was greater than that in the ampulla and highest during the secretory phase. Conversely, the tissue concentration of 6-keto-PGF1 alpha in the ampulla changed to that in the isthmus around the ovulatory phase. The OT-R showed the highest levels during the secretory phase in the isthmus, but showed little change in the ampulla throughout the menstrual cycle. It increased markedly in the isthmus but decreased in the ampulla. The present data suggest that the receptor concentrations in the human fallopian tube fluctuate in correlation with its physiological and histological status. It may, therefore, be concluded that the hormone-receptor interaction in this anatomical unit is closely involved in the reproductive functions of the human fallopian tube.