Metrial gland: structure, origin, differentiation and role in pregnancy.

Metrial gland is a separate class of cells associated with decidualization. These granulated cells, which are early detectable in the endometrium at implantation sites, become more prominent in the mesometrial triangle of rats as pregnancy advances. Typical ultrastructural features which include the presence of pleomorphic granules characterize these cells and recent observations indicate differentiation of these cells from lymphocyte-like precursors. Presence of IgG in the cytoplasm of metrial gland cells and their origin from bone marrow suggest an immune function.