Fibrinogen in Hamster Cauda Sperm.

Epididymis plays a vital role in promoting sperm maturation and maintaining sperm viability. It has been shown the presence of nonviable sperm in cauda epididymis. We previously identified a secretory protein (260/280KDa oligomers) of hamster cauda epididymal principal cells that binds to nonviable sperm. The 260/280KDa oligomers are composed of 64kDa FGL2 (fibrinogen-like protein-2) and 33kDa FGL1) (fibrinogen-like protein-1). In addition, we have demonstrated that FGL2 is a phospholipid-activated serine protease; the conversion of prothrombin to thrombin by FGL2 followed by the conversion of soluble fibrinogen to insoluble fibrin polymers by thrombin. In the present study, we have shown the presence of a 56kDa fibrinogen β in hamster cauda sperm. The potential role of fibrinogen in hamster physiology is being discussed.