Possible redox regulation of sperm motility activation

Mature spermatozoa are held in a quiescent state within the cauda epididymi s but show an instantaneous burst of vigorous motility on being released fr om this environment at ejaculation. Although the activation of motility is a defining moment in the life history of a spermatozoon, very little is kno wn about the molecular mechanisms controlling this process. In this minirev iew, I shall consider our current understanding of the activation process a nd put forward a model to explain this phenomenon, incorporating recent dat a on the redox regulation of cyclic adenosine monophosphate (cAMP) availabi lity in the male gamete.