Abstract
Primate sperm acquire functional maturity, including vigorous forward motility and the ability to fertilize an ovum, as they transit the unique, regional microenvironment of the epididymal lumen. Several proteins secreted into this luminal fluid are epididymal-specific and androgen-dependent, and thus contribute potentially to sperm maturation. For the adult male chimpanzee, we report the effects of GnRH antagonist-induced androgen deprivation on the histology of the epithelia and interstitium composing the ductuli efferentes, ductus epididymis, proximal ductus (vas) deferens. After 21 days of androgen deprivation, epididymal tissues exhibit characteristic atrophic changes, including cellular disorganization, degradation, and loss of structures. Androgen-deprived cytoplasm is differentially and characteristically disrupted, vacuolated, and reduced in volume, resulting in decreased epithelial height and loss of stereocilia. Most principal cell nuclei appear hyperchromatic, smaller in size, more irregular in outline, and disordered in arrangement, while others appear swollen and vacuolated. Apical cells of the efferent ducts and the basal cells and microvillar borders of the ductus epididymis seem minimally affected by androgen deprivation. Such histologically differential responses suggest correspondingly that androgen is differentially essential to the maintenance of the epididymis and thus to normal functioning of the component tissues. Therefore, epididymal epithelia directly and their secretions indirectly are differentially androgen-dependent.