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, immunohisto chemical 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 i ncrease of Le(y) in luminal surface from proliferative to periovulator y (P < 0.001), and from periovulatory to postovulatory (P < 0.05), pha ses. Le(y) then remained constant in the midsecretory phase and decrea sed (P < 0.01) during the premenstrual phase. Le(y) score in glands di d not change between the phases, except in midsecretory phase when it was higher than that in other phases (P < 0.05), The stromal compartme nt showed no statistically significant changes. The profiles of endome trial Le(y) on day 6 after ovulation in mated fecund cycles with or wi thout early luteal phase mifepristone treatment were also examined. Fe males were allowed to cohabit with males during days 8-16 of their ovu latory cycles and were injected s.c. with vehicle (n = 7) only, or wit h a single dose of mifepristone (2 mg/kg body weight; n = 8) on day 2 after ovulation, Significant decreases in the area and optical absorpt ion 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 immuno precipitate for Le(y) with or without mifepristone treatment. The expr ession of Le(y) in the endometrial epithelial compartment appears to b e influenced by progesterone and may be associated with endometrial re ceptivity prior to implantation in the rhesus monkey.