Ultrastructure of the Bull Seminiferous Tubule Supporting Cells with Special Consideration of the Cell Junctions

Abstract

This study represents an e1ect;onmicroscopic examination of seminiferous tubule epithclium of the bull, with special attention to the cell types and junctional complexes betwcen cells whim contribute to the blood-testis barrier. In general seminiferous epithelium of the bull resembles that of other animals with some alterations in supportive cell types and organization of junctional complexes between epithelial cells. These differences are illustrated a n d discussed in regard to their possible functional significance.

Ultrastructure of the Bovine Testis in Cattle (Bos taurus): New View

“…As reported by Rawlings et al [ 21 ], the differentiation of mature Sertoli cells appears to be complete between 30 and 40 weeks of age. The initial data from the 1960s to the 1980s indicated that there may be two types of Sertoli cells in the testes, namely dark and light cells [ 4 , 31 , 32 , 33 ]. Among the cells lining the seminiferous tubules in the calves examined, elongated dark supporting cells extending from the base towards the lumen were also observed.…”

“…In certain areas, the thin cytoplasm of dark supporting cells develops protrusions through which they connect with each other and form a kind of physiological communication network. Bielańska-Osuchowska and Sysa [ 4 ] observed two types of Sertoli cells, dark and light, in 14–15-month-old bulls. Dark Sertoli cells, characterized by their electron-dense cytoplasm and indistinct nucleus, were rarely observed within the bovine seminiferous tubule.…”

“…The author of the latter study suggested that the difference in electron density of the supporting cells was related to their varying reactivity to the absence of gonadotropin hormones. On the other hand, Bielańska-Osuchowska and Sysa [ 4 ] indicated that these are the dark Sertoli cells that produce steroids. In our previous studies using a light microscope, it was not possible to distinguish Sertoli cells [ 16 ].…”

“…The information published to date has focused on a detailed morphological analysis of spermatozoa and the seminiferous epithelium cycle in this animal species, with many studies published back in the 1980s. The available data on the analysis of the ultrastructure of male reproductive organs in cattle mainly concern sexually mature bulls [ 4 , 5 , 6 , 7 , 8 ]. Thus far, the literature data in calves mainly include histological analyses using a light microscope [ 9 , 10 , 11 , 12 ].…”

Ultrastructural and morphometrical analyses of Leydig and Sertoli cells in the testes of rats with hereditary polydactylism

“…The presence of dark Sertoli cells in the seminiferous tubules of sexually mature males has also been reported in pigs, cattle, and humans. In boars and bulls, although the metabolic states of the dark Sertoli cells and the light Sertoli cells differ (Osman, 1978;Bielanska-Osuchowska and Sysa, 1981), the physiological significance of these dark cells is unknown. Dark Sertoli cells have been found in humans with testicular feminization, and degenerative alter¬ ations such as folded nuclear membranes, dilated agranular endoplasmic cisternae and swollen mitochondria have been observed (Justrabo et al, 1978;Millonig et al, 1978).…”