Castration causes an increase in lysosomal size and upregulation of cathepsin D expression in principal cells along with increased secretion of procathepsin D and prosaposin oligomers in adult rat epididymis

In the epididymis, lysosomal proteins of the epithelial cells are normally targeted from the Golgi apparatus to lysosomes for degradation, although their secretion into the epididymal lumen has been documented and associated with sperm maturation. In this study, cathepsin D (CatD) and prosaposin (PSAP) were examined in adult epididymis of control, and 2-day castrated rats without (Ct) and with testosterone replacement (Ct+T) to evaluate their expression and regulation within epididymal epithelial cells. By light microscope-immunocytochemistry, a quantitative increase in size of lysosomes in principal cells of Ct animals was noted from the distal initial segment to the proximal cauda. Androgen replacement did not restore the size of lysosomes to control levels. Western blot analysis revealed a significant increase in CatD expression in the epididymis of Ct animals, which suggested an upregulation of its expression in principal cells; androgens restored levels of CatD to that of controls. In contrast, PSAP expression in Ct animals was not altered from controls. Additionally, an increase in procathepsin D levels was noted from samples of the epididymal fluid of Ct compared to control animals, accompanied by an increased complex formation with PSAP. Moreover, an increased oligomerization of prosaposin was observed in the epididymal lumen of Ct rats, with changes reverted to controls in Ct+T animals. Taken together these data suggest castration causes an increased uptake of substrates that are acted upon by CatD in lysosomes of principal cells and in the lumen by procathepsin D. These substrates may be derived from apoptotic cells noted in the lumen of proximal regions and possibly by degenerating sperm in distal regions of the epididymis of Ct animals. Exploring the mechanisms by which lysosomal enzymes are synthesized and secreted by the epididymis may help resolve some of the issues originating from epididymal dysfunctions with relevance to sperm maturation.Fil: Carvelli, Flavia Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Aguilera, Andrea Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Zyla, Leila Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Pereyra, Laura Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Morales, Carlos R.. McGill University; CanadáFil: Hermo, Louis. McGill University; CanadáFil: Sosa Escudero, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentin

Endocrine Regulation of Male Fertility by the Skeleton

Although the endocrine capacity of bone is widely recognized, interactions between bone and the reproductive system have until now focused on the gonads as a regulator of bone remodeling. We now show that in males, bone acts as a regulator of fertility. Using co-culture assays, we demonstrate that osteoblasts are able to induce testosterone production by the testes, while they fail to influence estrogen production by the ovaries. Analyses of cell-specific loss- and gain-of-function models reveal that the osteoblast-derived hormone osteocalcin performs this endocrine function. By binding to a G-protein coupled receptor expressed in the Leydig cells of the testes, osteocalcin regulates in a CREB-dependent manner the expression of enzymes required for testosterone synthesis, promoting germ cell survival. This study expands the physiological repertoire of osteocalcin, and provides the first evidence that the skeleton is an endocrine regulator of reproduction

Quantitative study of the spermatogonial stem cell population of the rat

The spermatogonial stem cell population of adult rats was analyzed quantitatively in whole mounts of seminiferous tubules and in radioautographed sections of testes collected at various time intervals after injections of 3H-thymidine. Various classes of type A spermatogonia were identified on the basis of their nuclear morphology and topographical distribution along the tubular basement membrane. The data suggested that the isolated type A spermatogonia were generally non-proliferative and were possibly equivalent to the "reserve stem cells" postulated by Clermont and Bustos-Obregon (1968). Paired type A spermatogonia also appeared to belong to this class of cells. Type A1 spermatogonia, which formed linear groups of more than four cells, originated during the peak of mitosis of type A4 spermatogonia. The data indicated that the type A1 spermatogonia were produced by some type A4 cells and/or a variant of this type of cells showing an irregular lobed nucleus (A irregular). The remaining type A4 cells produced differentiated spermatogonia (Intermediate and type B) which generated spermatocytes. Type Al cells ae well ae type A2, A3 and A4, which derive from each other, thus constituted a class of "renewing stem cells"

The structure of the limiting membrane of seminiferous tubules in the rat and monkey.

The limiting membrane of rat and monkey seminiferous tubules was investigated by light and electron microscopy. The myoid layer of the rat limiting membrane in addition to myoid cells, contained cells with a pale staining cytoplasm referred to as light cells. These cells were also observed in the interstitial space and on occasion between the adventitial layer and outer lamella of the limiting membrane. Hence it appeared that some of these cells miqht enter the limiting membrane from the interstitial space. The morphological features of the light cells were such that they could not be classified as monocytes, macrophages or lymphocytes. They did, however, bear resemblance to the granular leucocytes of the epididymis and hence appeared to belong to the same class of cells. The exact identity of these elements remains to be clarified. In whole mounts of rat tubules, light cells were readily identified by their polymorphous, "C"-shaped nucleus. Quantitative studies on these cells revealed that they were a numerous and regular component of the limiting membrane, but that they varies in number during the cycle of the seminiferous epithelium. It also showed that they were capable of dividing and degenerating and that they were sensitive ta X-rays. In the limiting membrane of monkeys, light cells were also present in addition to myoid cells. The distribution of collagen, elastin and microfibrils was also investigated and described.La membrane limitante des tubes séminifères du rat et du singe a été étudiée en microscopie optique et électronique. Chex le rat, au niveau de la couche des cellules myoides, on trouvé des cellules avec un cytoplasme pâle et qui présente certaines caractéristiques des leucocytes. Ces cellules sont présentes dans le tissu conjonctif intertubulaire ou dans l'adventice de la, membrane limitante ce qui suggère un passage de certaines de ces cellules de l'espace intertubulaire dans la membrane limitante. Ces cellules claires ne sont pas les précurseurs dès cellules myoides et ne peuvent être identifiées comme étant des macrophages, des monocytes ou des lymphocytes typiques. Elles ressemblent cependant aux leucocytes agranulaires présents dans l'épithélium épididymaire dont la nature exacte reste à être déterminée. En microscopie optique les cellules claires sont facilement identifiables dans des tubes séminifères disséqués et montés in toto. Une étude quantitative de ces cellules claires nous montre qu'elles sont fréquentes et que leur nombre varie, au cours du cycle de l'épithélium séminifère. De plus ces cellules Se divisent et dégénèrent et par conséquent doivent se renouveler. Elles sont également sensibles aux rayons-X. Chez le singe des cellules claires sont également présentes parmi les cellules myoides de la membrane limitante. Dans cette membrane, la distribution du collagen, de l'élastine et de microfibrilles conjonctives a également été analysée