Morphological analysis of endocytosis in efferent ductules of estrogen receptor-alpha knockout male mouse

Lack of estrogen receptor (ER) results in fluid accumulation and dilation o f the efferent ductules, suggesting that the role of estrogen and ER in the male reproductive tract is related to fluid reabsorption in the ductules. In the present study, endocytosis of the nonciliated cells of the efferent ductules was compared morphologically between wild type (WT) and estrogen r eceptor-alpha, knockout (alpha ERKO) male mice. The epithelial cells lining the WT efferent ductules were tall columnar in shape, whereas those of the alpha ERKO were low columnar. Immunocytochemically, the nonciliated cells of both genotypes showed positive reactions of sulfated glycoprotein-2, but the reaction products were reduced in amount in the alpha ERKC. Electron m icroscopy revealed that the nonciliated cells of the WT had numerous organe lles for endocytosis such as coated pits and vesicles, tubules, endosomes, multivesicular bodies and lysosomes in the apical cytoplasm. These organell es were less developed in the nonciliated cells of the alpha ERKO. Morphome tric analysis indicated that there was a significant reduction in area of e ndocytotic apparatus in the nonciliated cells of the aERKO compared with th at of the WT. A tracer study using gold particles demonstrated that the non ciliated cells of both WT and aERKO efferent ductules were capable of takin g up luminal contents. These results suggest that reabsorption of the lumin al contents via endocytosis takes place in the efferent ductules but is gre atly reduced in amount in the absence of ER alpha. Anat Rec 263:10-18, 2001 . (C) 2001 Wiley-Liss, Inc.