Steroidal binding sites in the ampulla of the human fallopian tube--autoradiographic and biochemical study

Most of the morphological changes which occur during the different phases of the reproductive cycle are hormone-dependent. Thus, the aim of this work was to demonstrate the fluctuations in the availability of steroid binding sites in the ampullary segment of the tube during the menstrual cycle. Specimens were obtained during routine gynecological operations and were prepared for histological examination. In addition, determinations of specific binding of estradiol and progesterone (specific activity was about 100 Ci/mmol) were made in soluene-dissolved tissue of ampullary mucosa. Autoradiographic grain counts of tissues which were incubated with [3H]estradiol and [3H]progesterone were performed on histological sections. The epithelial cell binding capacity was higher than that of the cells in the underlying lamina propria and this was found throughout the cycle. Estrogen and progesterone binding capacity was higher during the proliferative phase and decreased markedly during the secretory phase. Tissue binding of steroids appears to be inversely related to serum levels, which are lower in the proliferative phase and rise during the secretory phase.