Fibronectin in reproduction

The fibronectin (FN) levels in human follicular fluids have been shown to correlate well with follicular size and oocyte maturity, suggesting a role of FN in oocyte maturation. When added to the culture medium, the synthetic peptide Gly-Arg-Gly-Asp-Ser (GRGDS), which specifically inhibits the cell-binding of FN, has been shown to inhibit both spontaneous resumption of meiosis and gonadotropin-releasing hormone-induced meiosis of the oocytes. In another set of experiments, GRGDS has been found to inhibit the in vitro cleavage of mouse embryos by a still unknown mechanism.