GRGDSPK (EMD 56574) is a peptide incluing Arg-Gly-Asp (RGD). GRGDSPK (EMD 56574) is an competitive and reversible inhibitory peptide for inhibiting integrin-fibronectin binding. GRGDSPK is used to study the role of integrins in bone formation and resorption. In Vitro GRGDSPK (EMD 56574; RGD; 0.1-50 μM; for 4 days) inhibits mineralization in a dose-dependent manner as determined by measuring calcium content and 70 bonehnit area of tissue in parietal bones 18 days old isolated from pregnant Sprague-Dawley rats. GRGDSPK (10, 50 μM; for 4 days) dramatically alteres bone morphology, with a disruption of osteoblast and mineralized matrix organization. GRGDSPK (RGD; 250 μM), added to the medium, effectively blocks integrin-fibronectin binding and significantly increases the average size of wild-type cell aggregates. When GRGDSPK (250 μM) is added, wild-type mesendodermal progenitors exhibits strongly reduced adhesion forces and work, indicating that the detachment parameters recorded are specific for fibronectin and that integrins expressed in mesendodermal progenitors are involved. GRGDSPK (RGD-containing, 1.5 mM, 1.0 mM, and 0.5 mM) and RGD-mod-ified peptides impair the ability of sperm to fertilizebovine oocytes, illustrated by a reduction in cleavage in a dose-dependent manner. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid