Separation of non-sperm components from seminal preparations and effect on the analysis of sperm proteins

The presence of non-sperm components (NSC) in "washed" rabbit epididymal and ejaculated collections and their interference with the analysis of sperm proteins have been demonstrated. NSC were also found in ejaculates from normal and vasectomized humans and from vasectomized rabbits, and in epididymal preparations from guinea pigs. They comprise about 80% of the total number of particles in rabbit ejaculates and 35% in human ejaculates. The dry weight is approximately equally distributed in rabbit ejaculates between NSC and sperm. The majority of the LDH isozyme activity of the "washed particles" in an ejaculate were associated with the NSC and this study shows that "washed particle" preparations are not equivalent to sperm and that NSC must first be separated from the sperm themselves for studies of sperm proteins to be meaningful. A method for the separation of the NSC from the sperm by equilibrium sedimentation in gradients of sucrose-D20 is described.