Epididymal constituents and related substances in the storage of spermatozoa: a review

In vertebrate animals, the duration of storage of viable spermatozoa in the epididymis varies from a few hours in birds to many months in reptiles and bats. The available information on the unusual composition of the epididymal luminal fluid is summarized, and the effect of the various constituents on sperm motility is described. Spermatozoa would probably be best stored in an immotile state and some constituents of epididymal luminal fluid may be able to inhibit the motility of mammalian spermatozoa during storage in vitro. If this effect can then be removed at the time of insemination, by changing the spermatozoa to a different medium, such a procedure may allow storage of spermatozoa at room or even body temperature for extended periods.