Effects of luteinizing hormone and androgen on the development of rat progenitor Leydig cells in vitro and in vivo

Progenitor Leydig cells are derived from stem cells. The proliferation and differentiation of progenitor Leydig cells significantly contributes to Leydig cell number during puberty. However, the regulation of these processes remains unclear. The objective of the present study was to determine whether luteinizing hormone （LH） or androgen contributes to the proliferation and differentiation of progenitor Leydig cells. Fourteen-day-old male Sprague-Dawley rats were treated for 7 days with NalGlu, which is a gonadotropin- releasing hormone antagonist, to reduce the secretion of LH in the pituitary and thus, androgen in the testis. Rats were co-administered with LH or 7a-methyl-nortestosterone （MENT）, which is an androgen resistant to metabolism by 5a-reductase 1 in progenitor Leydig cells, and the subsequent effects of LH or androgen were measured. 3H-Thymidine was also intravenously injected into rats to study thymidine incorporation in progenitor Leydig cells. Progenitor Leydig cells were examined. NalGlu administration reduced progenitor Leydig cell proliferation by 83%. In addition, LH or MENT treatment restored Leydig cell proliferative capacity to 73% or 50% of control, respectively. The messenger RNA levels of proliferation-related genes were measured using real-time PCR. The expression levels of Igfl, Lifr, Pdgfra, Bcl2, Ccnd3and Pcnawere upregulated by MENT, and those of Pdgfra, Ccnd3and Pcnawere upregulated by LH. Both LH and MENT stimulated the differentiation of progenitor Leydig cells in vitro. We concluded that both LH and MENT were involved in regulating the development of progenitor Leydig cells.

Regulation of blood-testis barrier dynamics by the mT0RCl/rpS6 signaling complex:an in vitro study

During spermatogenesis, developi ng germ cells that lack the cellular ultrastructures of filopodia and lamellipodia gen erally found in migrating cells, such as macrophages and fibroblasts, rely on Sertoli cells to support their transport across the seminiferous epithelium. These in elude the transport of preleptote ne spermatocytes across the blood-testis barrier (BTB), but also the transport of germ cells, in particular developing haploid spermatids, across the seminiferous epithelium, that is to and away from the tubule lumen, depending on the stages of the epithelial cycle. On the other hand, cell junctions at the Sertoli cell-cell and Sertoli-germ cell in terface also un dergo rapid remodeli ng, invo Iving disassembly and reassembly of cell j un ctions, which, in turn, are supported by actin- and microtubule-based cytoskeletal remodeling. Interestingly, the underlying mechanism(s) and the invoIving biomolecule(s) that regulate or support cytoskeletal remodeling remain largely unknown. Herein, we used an in vitro model of primary Sertoli cell cultures that mimicked the Sertoli BTB in vivo overexpressed with the ribosomal protei n S6 (rpS6, the down stream signali ng protein of mammalian target of rapamycin complex 1 [mTORCl]) cloned into the mammalian expression vector pCI-neo, namely, quadruple phosphomimetic and constitutively active mutant of rpS6 (pCI-neo/p-rpS6-MT) versus pCI-neo/rpS6-WT (wild-type) and empty vector (pCI-neo/Ctrl) for studies. These findings provide compelling evidence that the mT0RCl/rpS6 signal pathway exerted its effects to promote Sertoli cell BTB remodeling. This was mediated through changes in the organization of actin- and microtubulebased cytoskeletons, involving changes in the distribution and/or spatial expression of actin- and microtubule-regulatory proteins.

Alterations of gene profiles in Leydig-cell-regenerating adult rat testis after ethane dimethane su Ifonate-treatment

成年睾丸间质细胞（ALC）是睾丸中产生雄激素的唯一内分泌细胞，只占有睾丸细胞的1％-5％。大鼠睾丸中的睾丸间质细胞被EDs去除后能够再生。本研究中，我们主要研究了大鼠睾丸经EDS处理后睾丸间质细胞再生及基因的变化图谱。EDS处理后7、21、35、90天后分析血清中睾酮、睾丸基因图谱和一些类固醇生成相关的蛋白变化情况。EDS处理后第7天睾丸中睾酮水平几乎检测不到，然后开始恢复。处理后7天，81个基因下调2倍或者更多，其中48个基因检测不到，包括类固醇合成通路中的蛋白Star、Scarbl、Cypllal、Cypl7al、Hsd3bl、CyplblICyp2al。这些基因在21天开始表达增多，到90天已经完全恢复到正常水平。89个基因上调2倍或者更高，nPkib。这些上调的基因到90天恢复正常；其中Cyp2al直到35天才开始恢复，表明这个基因只在成年睾丸间质细胞中表达，不在前体细胞中表达。qPCR，Westernblot、半定量免疫组织染色检测了随机抽取的基因和蛋白确认其变化情况。