On the ultrastructure of the male reproductive tract in the Siberian hamster (Phodopus sungorus campbelli). I. The ductuli efferentes.

The efferent ducts of the Siberian hamster were studied using transmission electron microscopy. Structural evidence indicates the presence of three cell types. First, in the nonciliated cell, the apical cytoplasm was replete with coated vesicles and pits and several classes of tubular profiles. Dense fields of microvilli characterize the apices of these cells. Populations of dense bodies were present together with large nonmembrane-bound structures containing membrane fragments and amorphous, homogeneously electron-dense material. The significance of the latter 'juxtanuclear bodies' remains unresolved. Basally, elaborate plasma membrane interdigitations and intercellular canaliculi suggest the possibility of intercellular transport. Second, a cell was identified whose surface was replete with microvilli, among which were scant numbers of true cilia. Ciliogenesis was evident. Despite dense populations of microvilli, these cells exhibited none of tubular complexes characteristic of nonciliated cells. Third, there were cells whose surfaces exhibited dense populations of cilia and scant numbers of microvilli. Coated vesicles and apical tubular complexes were absent, but these cells contained multivesicular bodies, lysosomes and lipofuscin granules. Structural evidence points to three functionally different cell types in Siberian hamster efferent ducts.