Ultrastructure of the Mouse Epididymal Duct with Special Reference to the Regional Differences of the Principal Cells

Epididymides from six white rats have been examined by standard histological techniques. The epididymis, consisting of rete, efferent ducts, and epididymal duct possesses an epithelium containing six cell types-principal, basal, ciliated, apical, halo, and clear cells-each of which is described. Cytoplasmic differences in the principal cells permit two zones to be recognized in the efferent ducts. The principal cells along the length of the epididymal duct vary in a number of features such as: height, depth and distribution of staining, the incidence, size, and intracellular distribution of vacuoles, the shape of the nuclei, and the distribution of chromatin within them. Such differences permit definition of six major zones, some of which may be further subdivided. Variations in the histological characteristics of the various zones in different individuals have been described. These zones have been related to the usual anatomical divisions of head, isthmus, and tail. The lumen of the epididymis contains spermatids and their breakdown products in addition to spermatozoa. The latter vary in density (number per unit volume), and in their arrangement with respect to one another, in the various zones of the efferent epididymal ducts. The implications of these histological findings in the physiology of the epididymis are discussed.

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Differential expression of cathepsins B and D in testis and epididymis of adult rats.

Journal of Histochemistry & Cytochemistry ◽

10.1177/43.5.7730593 ◽

1995 ◽

Vol 43 (5) ◽

pp. 545-557 ◽

Cited By ~ 38

Author(s):

S A Igdoura ◽

C R Morales ◽

L Hermo

Keyword(s):

Cathepsin B ◽

Cathepsin D ◽

Regional Differences ◽

Intermediate Zone ◽

Basal Cells ◽

Adult Rats ◽

Clear Cells ◽

Principal Cells ◽

Caput Epididymidis ◽

In Cells

Cathepsins are specific proteases in lysosomes that participate in the degradation of proteins, some of which are derived from endocytosis. In this study we examined the immunocytochemical localization of cathepsin B and D antibodies in cells of rat testis and epididymis, using light and electron microscopic immunocytochemistry. In testis, cathepsin D was immunolocalized over lysosomes of Sertoli cells and Leydig cells and on the acrosome of spermatids. Cathepsin B was found over lysosomes of macrophages. Non-ciliated cells of the efferent ducts revealed intense immunogold labeling over lysosomes with both anti-cathepsin B and D antibodies. In epididymis, cathepsins B and D showed marked variations in expression over the different epithelial cells and regional differences for a given cell type. Anti-cathepsin D antibodies showed intense labeling over lysosomes of principal cells in the corpus and proximal cauda. In contrast, anti-cathepsin B antibodies revealed intensely labeled lysosomes of principal cells of the distal initial segment, intermediate zone, and caput epididymidis, with weaker labeling in other regions. Clear cells of the proximal caput epididymidis revealed intensely labeled lysosomes for anti-cathepsin D antibodies. In the distal caput, clear cells showed a variable reaction pattern from intensely labeled to unreactive. Basal cells of teh intermediate zone and proximal caput region were intensely reactive for anti-cathepsin D antibodies. There was no staining over clear or basal cells with anti-cathepsin B antibodies. Taken together, these results demonstrate cell-specific and regional differences in the distribution of cathepsins B and D in cells of the male reproductive system. Such results suggest substrate specificity with regard to protein turnover within lysosomes of cells of testis and epididymis.

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