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Abstract: The aim of the present study was to investigate the expression and role of c-Flip long isoform (c-FlipL), a known anti-apoptotic protein. No data are currently available on c-FlipL in male gonad before puberty; therefore, this study was carried out in prepuberal mouse testis. We investigated pachytene spermatocytes and spermatogonia by immunostaining of testis sections and found a strong and specific expression of c-FlipL in pachytene spermatocytes, while spermatogonia expressed very low levels of c-FlipL. This finding inversely correlated with the caspases activity, which was higher in spermatogonia as compared to pachytene spermatocytes. Other experiments carried out in an organ-culture model revealed that Fas-induced apoptosis was higher in spermatogonia as compared to pachytene spermatocytes. These data suggest that c-FlipL may play a role as an anti-apoptotic molecule in the prepuberal mouse testis and open new perspectives in the comprehension of the mechanisms controlling germ cells apoptosis. [Copyright &y& Elsevier]

Abstract: The contractile activity of peritubular tissue is responsible for the propulsion of spermatozoa along the lumen of seminiferous tubules toward the hilum of the testis. This function is performed by specialized contractile cells [peritubular smooth muscle cells (PSMC)] in response to the locally produced agonist, endothelin (ET). Here, we review current information on the complex ET-mediated control of peritubular contractility. In addition, we report new data demonstrating that the relaxant peptide adrenomedullin is produced by Sertoli cells and interferes with ET-mediated contraction of PSMC. Given the relevance of the seminiferous tubule sperm output for male fertility, the detailed definition of the mechanisms controlling peritubular contractility could contribute in different ways to novel therapeutic opportunities and provide potential targets for contraceptive strategies. [Copyright &y& Elsevier]