Immunolocalization of Le(y) oligosaccharide in endometrium during menstrual cycle and effect of early luteal phase mifepristone administration on its expression in implantation stage endometrium of the rhesus monkey.

Changes in carbohydrate expression on endometrial and blastocyst cell surfaces may play a critical role in the process of implantation. Le(y) is an oligosaccharide antigen which has been shown to be involved in blastocyst attachment in the mouse. In the present study, immunohistochemical distribution of Le(y) in endometrium during proliferative and secretory phases of normal menstrual cycles in the rhesus monkey was examined. Endometrial samples were collected on cycle days 7 (n=4), 13 (n= 4), 16 (n=4), 20 (n=4) and 25 (n=3). There was a gradual increase of Le(y) in luminal surface from proliferative to periovulatory (P < 0.001), and from periovulatory to postovulatory (P < 0.05), phases. Le(y) then remained constant in the midsecretory phase and decreased (P < 0.01) during the premenstrual phase. Le(y) score in glands did not change between the phases, except in midsecretory phase when it was higher than that in other phases (P < 0.05). The stromal compartment showed no statistically significant changes. The profiles of endometrial Le(y) on day 6 after ovulation in mated fecund cycles with or without early luteal phase mifepristone treatment were also examined. Females were allowed to cohabit with males during days 8-16 of their ovulatory cycles and were injected s.c. with vehicle (n=7) only, or with a single dose of mifepristone (2 mg/kg body weight; n=8) on day 2 after ovulation. Significant decreases in the area and optical absorption of immunoprecipitate were observed in the epithelial compartment (P < 0.01) following mifepristone treatment. There was no change in the stromal compartment either in area or in optical absorption of immunoprecipitate for Le(y) with or without mifepristone treatment. The expression of Le(y) in the endometrial epithelial compartment appears to be influenced by progesterone and may be associated with endometrial receptivity prior to implantation in the rhesus monkey.