The proposed research will investigate the process of sperm capacitation in the pig. The timing and conditions for capacitation in the ligated uterus will be defined. Plasma membrane and outer acrosome membrane will be isolated from capacitated pig sperm. Lipids will be extracted from whole sperm, plasma membrane and outer acrosome membrane to study changes associated with capacitation. Lipids to be identified and quantified include phospholipids, glycolipids, gangliosides and neutral lipids. The role of proteins in capacitation will be investigated. The ultrastructure of pig sperm during capacitation, the acrosome reaction and fertilization will be studied using the stain that is specific for sperm plasma membrane.