Lewis X(Le x) is stage specifically expressed on the surface of mammalian embryos. Histochemical evidences have showed that Le x is expressed in endometrium, and may be controlled by ovarian hormones. It has been reported that FUT9 gene is the real specific gene encoding α1, 3 fucosyltransferase for the synthesis of terminal fucose of Le x. In this article, the transcription of FUT9 and expression of Le x oligosaccharide antigen in mouse endometrium were investigated. The mice(22～25 g) were selected and treated as follows:(1) Estrous: females were checked by vaginal smears to determine their stage of estrus;(2) Early pregnancy: females were mated with males(1∶1), and the day of vaginal plug appearance was considered as day 1 of pregnancy;(3) Hormone replacement: after ovariectomy, mice were given subcutaneously estradiol benzoate and progesterone daily for 4 days. The results showed that the transcription level of FUT9 gene was:(1) periodically changed during estrous cycle: highest at estrus stage, and lowest at metestrus stage;(2) decreased obviously during early pregnancy, then maintained at a lower level from day 3 to day 5;(3) increased in the estradiol treatment group, and decreased obviously in the progesterone treatment group, and was at a middle level in the group treated with both estradiol and progesterone;(4) level of Le x carrying proteins on the surface of endometrium did it coincide fully with that of FUT9 gene transcription, which indicated that other factors may be also involved in the regulation of Le x expression in addition to the hormones. In summary, the expression of FUT9 gene in mouse endometrium is regulated by ovarian hormones, being up regulated by estrogen and down regulated by progesterone.
