Developmental changes in signalling transduction factors in maturing sperm during epididymal transit.

Testicular spermatozoa are incapable of fertilising eggs in vivo and the epididymal epithelium is responsible for creating a luminal environment conducive to the acquisition of fertilising capacity by the spermatozoa within it. It does this by modifying sperm membranes so that they can interact with stimuli from the female tract, and by supplying or removing low molecular weight compounds that modify sperm cytoplasmic composition. Both these extracellular and intracellular events associated with signal transduction and second messenger systems in maturing spermatozoa are reviewed here.