Biochemical Analysis of Glycosphingolipids in Murine Uterus and Human Uterine Endometrium with Special Reference to the Sexual Cycle

Abstract

Uterus is an organ in which cellular proliferation and differentiation are strictly controlled by sex steroid hormones. Since we found a characteristic expression of sulfatide (I³ SO₃-GalCer) in the human endometrium during its secretory phase, we decided to analyze developmental changes of glycolipids in murine uteri with special reference to the estrous cycle. Moreover, we analyzed sulfotransferase activity for the synthesis of sulfatide in the endometria in the proliferative and secretory phases and that in the epithelial and stromal cells derived from the human uterine endometrium. In the murine uterus, contents of GlcCer, LacCer, and Gb₄Cer were relatively constant both during estrus and diestrus, but those of Gb₃Cer and Gg₄Cer during estrus were significantly greater than those during diestrus. In contrast, GM₃ and sulfatide contents during diestrus were higher than those during estrus. This increase in GM₃ and sulfatide during diestrus was characteristically observed in the uterus after sexual maturity. In human uterine endometrium, sulfotransferase activity for the synthesis of sulfatide was found only in the epithelial cells, but not in the stromal cells. Furthermore, the synthetic potential of sulfatide in the human endometrium was higher in the secretory phase than in the proliferative phase. Thus, sulfatide metabolism in human endometrial epithelial cells as well as in the murine uterus is supposed to be well controlled under hormonal regulation, and sulfatide may participate in several reproductive functions of the uterus.