The effects of growth factors on laminin secretion by F9-derived primitive endoderm-like cells.

Abstract

Reichert's membrane (RM) is a basement membrane that is deposited on the inner surface of the trophectoderm (TE) just prior to implantation in mice and rats. Components of RM include laminin, type IV collagen, fibronectin and heparan sulfate proteoglycan. The parietal endoderm (PE) cells have been shown to synthesize laminin, type IV collagen and heparan sulfate proteoglycan present in RM, while it appears that the fibronectin in RM is contributed by the TE cells. The PE, RM and TE together form the parietal yolk sac, which nourishes the developing fetus. The PE cells arise from the first inner cell mass (ICM)-derived cell lineage, the primitive endoderm (PrE) cells. The PrE cells move away from the ICM and migrate along the TE, differentiating to PE cells at some point in this migration. Primitive endoderm cells also secrete laminin and type IV collagen, and it is the contention of this author that secretion of these extracellular matrix (ECM) glycoproteins by the PrE cells may provide the substratum for their migration by contributing to the initial formation of RM. This research project studied the possible growth factor regulation of laminin glycoprotein secretion by PrE-like cells. (Abstract shortened by UMI.)