This research aims to improve our understanding of sperm maturation, the process in the epididymis whereby immature sperm cells achieve the competency to later undergo capacitation and fertilization. The research will focus principally on the final events that are critical in acquisition by sperm of mature status. An extention of presently useful methodology for assessment of functional sperm maturation will include use of our in vitro capacitation and in vitro fertilization procedure. The investigation will encompass various steroidal influences on promoting sperm maturation in organ culture and experiments to link influences of steroids with epedidymal proteins that can directly effect maturation of immature sperm cells. The work will include morphological studies at the light and electron microscope levels. Attention will be paid to experimentally induced changes in sperm motility and longevity in addition to fertilizing ability. Identification of essential components of the pathway to maturation will be followed-up by immunological and chemical approaches toward control.