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Basal cells are present in the columnar pseudostratified epithelium covering the epididymis of all mammalian species, which regulates the microenvironment where the functionally incompetent germ cells produced by the testis are matured and stored. Striking novelties have come from investigations on epididymal basal cells in the past 30-40 years. In addition to an earlier hypothesised scavenger role for basal cells, linked to their proven extratubular origin and the expression of macrophage antigens, basal cells have been shown to be involved in cell-cell cross-talk, as well as functioning as luminal sensors to regulate the activity of principal and clear cells. Involvement of basal cells in the regulation of electrolyte and water transport by principal cells was hypothesised. This control is suggested to be mediated by the local formation of prostaglandins. Members of the aquaporin (AQP) and/or aquaglyceroporin family (AQP3, AQP7 and AQP8) are also specifically expressed in the rat epididymal basal cells. Transport of glycerol and glycerylphosphorylcholine from the epithelium of the epididymis to the lumen in relation to sperm maturation may be mediated by AQP. Most probably basal cells collaborate to the building up of the blood-epididymis barrier through cell adhesion molecules, implying an involvement in immune control exerted towards sperm cells, which are foreigners in the environment in which they were produced. This review summarises the striking novelties obtained from morphophysiological investigations after David W. Hamilton stated 'epididymal basal cells are an enigma' in the 1970s. In addition to an earlier hypothesised scavenger role linked to the expression of macrophage antigens, basal cells have been shown to be involved in cell-cell cross-talk and to function as luminal sensors regulating epithelial activity. [ABSTRACT FROM AUTHOR]

The surface epithelium of the vas deferens of Agouti paca, a wild and large South American rodent, was basically formed by principal and basal cells being only the principal cells related to endocytosis processes and also secretion taking base on their cytoplasmic ultrastructural features. Principal cell of vas deferens epithelium were characterized mainly by presence of vesicles with several shapes, sizes and internalized content at their apical cytoplasm occurring smaller pits and pale small vesicles seen next to the apical brush border of microvillus. Moreover, coated vesicles, smooth surface vesicles and great vesicles; multivesicular bodies, endosomes and lysosomes were seen. Presence of an apocrine secretory apparatus was also viewed, showing apical cytoplasmic expansions protruding into the vas deferens luminal compartment. The basal flattened cells, without luminal surface contact, occurred next to the basement membrane of the ductus, and did no exhibit special ultrastructural features. [ABSTRACT FROM AUTHOR]