Glycosylation-dependent cell adhesion molecule 1 (GlyCAM-1) is an endothelial
glycoprotein secreted in lymph nodes that serves as a
ligand for leukocyte cell surface
selectin and mediates lymphocyte extravasation. In the present studies, rabbit anti-rat
GlyCAM-1 IgG was used in immunochemical analyses of GlyCAM-1-like
protein in the ovine uterus. In cyclic ewes,
GlyCAM-1 expression increased in the endometrial
luminal epithelium (LE) and shallow glandular epithelium (cGE) between Days 1 and 5 and then decreased between Days 11 and 15. In pregnant ewes,
GlyCAM-1 in the LE and cGE was low on Days 11 and 13, increased on Day 15, and was abundant on Days 17 and 19. Immunoreactive
GlyCAM-1 was also detected in the conceptus trophectoderm on Days 13-19. Staining for
GlyCAM-1 in the smooth muscle of the vasculature and myometrium was constitutive, and no staining was detected in the stroma. An immunoreactive
protein of approximately 45 kDa was identified in endometrial extracts and uterine
flushings from cyclic and pregnant ewes. In pregnant ewes, the relative amount of immunoreactive
GlyCAM-1 in uterine
flushings was low on Days 11 and 13 but high on Days 15 and 17. Results suggest that a GlyCAM-1-like
protein may be a secretory product of the endometrial epithelium and/or conceptus trophectoderm. Patterns of distribution observed for immunoreactive GlyCAM-1-like
protein in the endometrial epithelium, combined with proposed functions for lymphoid
GlyCAM-1, suggest that this
mucin glycoprotein may be involved in conceptus-maternal interactions during the periimplantation period of pregnancy in sheep.