Characterization of epididymal proteins Electrophoretic analysis of epididymal fluid proteins

© 1998 Journals of Reproduction and Fertility 1359-6004/98 $12.50 Before mammalian spermatozoa can interact with the egg in vivo, they are subjected to post-testicular modifications in the male as well as in the female genital tract. The evidence that this post-testicular maturation process requires exposure to a specific microenvironment within the epididymis has been reviewed elsewhere (Orgebin-Crist, 1987; Robaire and Hermo, 1988; Blaquier et al., 1989). However, the functions of the components of this microenvironment are still poorly understood (for review see Hinton et al., 1995; Turner, 1995). Moreover, there is uncertainty as to the essential place of the epididymis in the chain of conception. This is especially true for the human epididymis (for review see Bedford, 1994). Nevertheless, the possible use of inhibiting epididymal functions in the development of contraceptives for men has raised considerable interest. An important aspect of epididymal sperm maturation and storage seems to be the interaction of luminal fluid proteins with the sperm surface (for review see Brooks, 1987; OrgebinCrist, 1987; Blaquier et al., 1989; Hinton et al., 1995). These proteins are thought to be synthesized post-testicularly by the epithelial cells lining the epididymal duct, and secreted apically into the lumen, where they come into contact with, and may be adsorbed to, the surface of spermatozoa. During the last decade, various methods have been used to characterize these proteins. This review will compare the methods applied and summarize the results obtained by the various approaches, emphasizing the molecular characterization of the most abundant human epididymal proteins. Characterization of epididymal proteins