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Testis Barrier (testis + barrier)
Selected AbstractsChanges in the expression of claudins and transepithelial electrical resistance of mouse Sertoli cells by Leydig cell cocultureINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 5 2003M. C. Gye Summary In the testis, tight junctions (TJs) between adjacent Sertoli cells are important for the formation of blood,testis barrier (BTB). To verify the role of paracrine interactions between the Sertoli and Leydig cells in the structure and function of BTB in testis, the expression of claudin-1 and -11, and transepithelial electrical resistance (TER) of the mouse Sertoli cells were examined under the Leydig cell coculture. TER of Sertoli cell monolayer was significantly larger under the Leydig cell coculture in comparison with the control culture. Meanwhile, the expression of claudin-1 slightly decreased and claudin-11 significantly increased in the Sertoli cells in the Leydig cell coculture compared with control. Testosterone significantly increased claudin-11 expression in cultured Sertoli cells. Taken together, it suggested that Leydig cell coculture changed the structure and functions of inter-Sertoli TJs in vitro. Interactions between Leydig and Sertoli cells might be involved in the development of functional blood testis barrier in mouse testis. [source] Evidence for the presence of 5,-deiodinase in mammalian seminal plasma and for the increase in enzyme activity in the prepubertal testisINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 4 2000Brzezi, lebodzi Thyroid hormones are critical for structural and functional development of the testis and Sertoli cells are considered true target cells for triiodothyronine (T3). However, the role of thyroid hormones in the adult testis seems to be minimal and the mechanism by which they affect testicular function is not known. Due to the existing blood,testis barrier the concentration of thyroid hormones in seminal plasma is kept lower than in blood plasma. We have found that T3 may reach the testis not only from the circulation but also from local enzymic conversion of thyroxine to T3. The presence of the enzymic activity responsible for thyroxine 5,deiodination and for generating T3 locally was also found in boar's seminal plasma. The seminal plasma 5,-deiodinase (5,-D) appeared to be predominantly the propylthiouracil (PTU)-insensitive type II isoenzyme found, so far, in tissues where it plays a role in paracrine signalling. It contains selenocysteine in its molecule (inhibition by aurothioglucose), and has an apparent Km for reverse-T3 as substrate of 0.36 n M and a Vmax 23.8 fmol I,/mg protein/min. Because the seminal plasma 5,-D is partially, but uncompetitively, inhibited by PTU, the presence in seminal plasma of two 5,-D isoenzymes (type I and II) cannot be excluded. The 5,-D activity in testes increased significantly between week 3 and 4, and this increase was concomitant with increase in testicular size. The relationship between testicular weight gain and age showed a similar characteristic change and corresponded to the change in 5,-D activity. Unlike in rodents, the testis of the prepubertal pig has thyroid hormone receptors in Sertoli cells, and suggests that in growing piglets, testicular 5,-D is a key factor regulating local supply of biologically active T3, and is an essential factor in testicular paracrine function. The present results are the first demonstration and characterization of the 5,-deiodinase in seminal plasma. [source] The role of dynamin 3 in the testis,JOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2007K.S. Vaid We report here that dynamin 3 in the testis is associated with structures termed tubulobulbar complexes that internalize intact intercellular junctions during sperm release and turnover of the blood,testis barrier. The protein lies adjacent to an actin-Arp2/3 network that cuffs the double plasma membrane tubular invagination at the core of each complex. To explore the possible relationship between dynamin 3 and nectin-based adhesion junctions, we transiently transfected DsRed-tagged dynamin 3 into MDCK cells stably transfected with eGFP-tagged nectin 2, one of the adhesion molecules known to be expressed in Sertoli cells at adhesion junctions. Cells transfected with the dynamin 3 construct had less uniformly distributed nectin 2 at intercellular contacts when compared to control cells expressing only nectin 2 or transfected with the DsRed plasmid alone. Significantly, tubular extensions positive for nectin 2 were visible projecting into the cells from regions of intercellular contact. Our findings are consistent with the conclusion that dynamin 3 is involved with tubulobulbar morphogenesis. Dynamin 3 also occurs in concentrated deposits around the capitulum and striated columns in the connecting piece of sperm tails suggesting that the protein in these cells may function to stabilize the base of the tail or serve as a reservoir for use during or after fertilization. J. Cell. Physiol. 210: 644,654, 2007. © 2006 Wiley-Liss, Inc. [source] Molecular dynamics of the blood,testis barrier components during murine spermatogenesisMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 7 2010Masataka Chihara The blood,testis barrier (BTB) separates the seminiferous epithelium into the adluminal and basal compartments. During murine spermatogenesis, preleptotene/leptotene spermatocytes migrate from the basal to the adluminal compartment through the BTB during stages VIII,IX. In the present study, we focused on the tight junction (TJ) molecules and analyzed their spatiotemporal expression during the murine seminiferous epithelial cycle. Structural analysis revealed that the principal components of the BTB, for example, claudin-3, claudin-11, occludin, and zonula occludens-1 (ZO-1), were localized at the basal and luminal sides of the preleptotene/leptotene spermatocytes during the migration stages (VIII,IX). Although we detected claudin-11, occludin, and ZO-1 throughout spermatogenesis, claudin-3 was only detected during stages VI,IX. Quantitative PCR using dissected seminiferous tubules from three stages (Early: II,VI, Middle: VII,VIII, Late: IX,I) clarified that the mRNA levels of TJ molecules were not correlated with the histoplanimetrical protein levels during spermatogenesis. Additionally, tubulobulbar complexes, considered to be involved in the internalization of TJ, were observed at the BTB site. Furthermore, a significant reduction in the mRNA levels of genes for the degradation of occludin (Itch) and endocytic recycling (Rab13) were observed during the Late and Middle stages, respectively. Therefore, we hypothesized that the lag between mRNA and protein expression of TJ molecules may be due to posttranslational modulation, for example, tubulobulbar complexes and endocytic recycling processes. In conclusion, these findings indicate that the integrity of the BTB is maintained throughout spermatogenesis, and the stage-specific localization of claudin-3 protein plays an important role in regulating BTB permeability. Mol. Reprod. Dev. 77: 630,639, 2010. © 2010 Wiley-Liss, Inc. [source] Analysis of the mRNA expression of the TGF-Beta family in testicular cells and localization of the splice variant TGF-,2B in testisMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 10 2006Lutz Konrad Abstract The transforming growth factors (TGF)-,, TGF-,1, TGF-,2, and TGF-,3, and their receptors [T,RI, T,RII, T,RIII (betaglycan)] elicit many functions in the testis, for example, they perturb the blood testis barrier (BTB). Although expression of the ligands and receptors have been investigated, the alternative splice variants are incompletely examined. We therefore have analyzed all ligands, the receptors, and the splice variants T,RIB, T,RIIB, and TGF-,2B in testicular cells from rat and mouse. In mouse, the novel transcript variant TGF-,2B was identified and was found in Leydig cells, spermatogonia, pachytene spermatocytes, and in the apical regions of the Sertoli cells in adult testis. Even though expression of the splice variant T,RIB could be shown in mouse and rat, we never found the isoform T,RIIB in the rat cell lines studied. Whereas in all testicular cells expression of all TGF-, ligands could be shown, receptor mRNA expression was slightly more diverse. Furthermore, expression pattern of the splice variants was more heterogeneous, for example, T,RIB was not detectable in adult Sertoli cells, primary peritubular cells, and immortalized peritubular cells. The heterogeneous expression of the receptors and especially of the splice variants might provide possible clues for the different functions of the TGF-, ligands in testicular cells. Mol. Reprod. Dev. © 2006 Wiley-Liss, Inc. [source] Immunohistochemical distribution of S-100 protein and subunits (S100-, and S100-,) in the swamp-type water buffalo (Bubalus bubalis) testisANDROLOGIA, Issue 3 2003M. B. C. Cruzana Summary. The distribution and localization of S-100 protein (S-100) and its subunits (S100-, and S100-,) 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-, showed the same distribution and localization with that of S-100. However, the cytoplasmic extension of the Sertoli cells in S100-, staining showed less staining intensity compared with that of S-100. S100-, 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-, 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-,, which was detected only in the modified Sertoli cells, is involved in the secretory activity of these cells that are related to exocrine function. [source] Importance of P-glycoprotein for drug disposition in humansEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 2003M. F. Fromm The ATP-binding cassette transporter P-glycoprotein is now recognized as an important determinant for disposition of multiple drugs. The use of P-glycoprotein-expressing cell lines, the generation of P-glycoprotein knockout mice as well as studies in animals and humans contributed to a better understanding on the role of active transport processes for drug disposition. P-glycoprotein is located in tissues with excretory function such as intestine, liver and kidney. Moreover, due to its expression in important blood,tissue barriers (blood,brain and blood,testis barriers), in lymphocytes and in placenta it limits tissue penetration of its substrates. Induction and inhibition of P-glycoprotein have now been identified as important underlying mechanisms of drug interactions in humans. Using selected examples, this review summarizes currently available data on the impact of P-glycoprotein for bioavailability of drugs, drug interactions and drug effects. [source] | |||||||||||||