
During their transit through the epididymis, spermatozoa undergo many biochemical modifications necessary to acquire flagellar motility and fertilizing ability. These modifications, collectively called sperm maturation, are well orchestrated along the epididymis. Sperm maturation requires the interaction of spermatozoa with proteins that are synthesized and secreted in a region-specific manner by principle cells of the epididymal epithelium and depend on highly regionalized gene expression patterns. But the regulatory processes that establish the discrete epididymal microenvironments remain yet largely unknown. Based on clinical observations, the role of the epididymis in human sperm maturation has been questioned but results obtained using animal models can be extrapolated to human with caution