Teguh Budipitojo

Immunohistochemical distribution of S-100 protein and subunits (S100-α and S100-β) in the swamp-type water buffalo (Bubalus bubalis) testis

The distribution and localization of S‐100 protein (S‐100) and its subunits (S100‐α and S100‐β) in the testis of swamp‐type water buffalo were investigated using immunohistochemistry. S‐100 was detected in the Sertoli cells in the convoluted seminiferous tubules, modified Sertoli cells lining the terminal segment of the seminiferous tubules and in the intratesticular excurrent ducts (straight tubules and rete testis). S100‐β showed the same distribution and localization with that of S‐100. However, the cytoplasmic extension of the Sertoli cells in S100‐β staining showed less staining intensity compared with that of S‐100. S100‐α showed a positive staining only in the modified Sertoli cells of the terminal segment of the seminiferous tubule. Endothelial cells of blood vessels were also positive with the proteins while the Leydig and spermatogenic cells showed a negative reaction. The localization of S‐100 in the testis of the water buffalo was in parallel with that of other artiodactyls which supports the hypothesis that this protein is a multifunctional protein. S100‐β in the Sertoli cells suggests that this protein is involved in establishing blood–testis barrier. Its presence in the modified Sertoli cells and in the epithelium of the excurrent ducts suggest secretory and absorptive function, respectively. Meanwhile, S100‐α, which was detected only in the modified Sertoli cells, is involved in the secretory activity of these cells that are related to exocrine function.

Ultrastructural localization of gastrin-releasing peptide (GRP) in the uterine gland of cow

Gastrin-releasing peptide (GRP) is thought to act mainly as a neurotransmitter and localized almost exclusively to neurons and neuroendocrine cells. Recently, the localization of GRP in mammalian uterus and placenta has been demonstrated. Moreover, the exocrine manner of GRP release was deduced in ewes from the distribution of GRP on the uterine gland cells and its secretion as well as in the circulation. However, these reports have been examined at light-microscopic level. The present study was designed to make clear the localization of GRP in the uterine gland cells of nonpregnant and pregnant cows using an avidin-biotin-peroxidase complex (ABC) method at light-microscopic level and a pre-embedding immunogold with silver enhancement method at electron-microscopic level. The light-microscopic observation showed positive staining for GRP immunoreactivity in the supranuclear region and in the secreted materials of the uterine gland cells. At the electron-microscopic level, the supranuclear secretory granules and the secreted materials on the surface of the cell were labeled with immunogold particles representing GRP immunoreactivity in the uterine gland cells of nonpregnant and pregnant cows. Western blotting analysis showed a larger molecular form of GRP in the endometrial tissues taken from nonpregnant and pregnant cows. The present results revealed the localization of GRP in the uterine gland cells at light- and electron-microscopic levels and suggested the release of GRP from the cell into the lumen of the gland by exocrine manner.

Immunohistochemical Localization of Inhibin Subunits in the Testis of the Bull

The differential localization of the inhibin β subunits βA and βB in the testis of adult bull was studied using specific monoclonal and polyclonal primary antibodies. Inhibin βA‐ and βB‐subunits were localized only in the Sertoli cells. The inhibin βA‐subunit was observed in the cytoplasm while the βB‐subunit was localized in the nucleus. No specific findings depending on spermatogenic stages were observed among the seminiferous tubules. Moreover, the inhibin α‐subunit was not detected in the testis of the bulls. In addition, no inhibin subunits were detected in the Leydig cells and spermatogenic cells. These findings indicate the presence of βA‐ and βB‐subunits in the bull, which may suggest a possibility that activin is produced and/or stored in the Sertoli cells and regulates spermatogenesis in an autocrine/paracrine manner. Moreover, the inhibin βB‐subunit may be produced in the nucleus but the functional meaning of this is not yet clear.