Localization and expression of steroid sulfatase in human fallopian tubes

Localization of steroid sulfatase, a membrane-bound microsomal enzyme, in human fallopian tubes was immunohistochemically investigated, and expression of RNA was confirmed by competitive RT-PCR. Human fallopian tubes were obtained from 10 patients in follicular and early luteal phases during gynecological laparotomy. An anti-human rabbit polyclonal antibody was prepared against sulfatase protein purified from human placenta. Total RNA was isolated from epithelium of fallopian tubes. A heterologous RNA competitor was designed, and competitive RT-PCR was carried out. Steroid sulfatase was localized to the cytoplasm of epithelial cells. With respect to the positive staining of cells, the number of positive secretory cells was higher than that of ciliated cells. A significantly higher number of positive cells was found in tissue obtained from the early luteal phase than that found in tissue from the follicular phase. An abundant expression of sulfatase mRNA in early luteal phase was also observed. This study demonstrates, for the first time, that steroid sulfatase is localized to human epithelial cells and that steroid sulfatase staining and mRNA expression changes with the menstrual cycle. These results suggest that sulfatase in the fallopian tube may be involved in controlling the local steroid environment, which appears to regulate aspects of the physiological reproductive function of the fallopian tube.