Immunohistochemical localisation of PDE5 in Leydig and myoid cells of prepuberal and adult rat testis

Abstract

Expression of phosphodiesterase 5 (PDE5) in the rat testis at several pre and postnatal developmental stages was investigated by immunohistochemistry. The enzyme was localised in vascular smooth muscle cells, as well as in Leydig and peritubular cells. The latter were identified as myoid, based on their immunoreactivity to desmin and alpha-smooth muscle actin. The presence of PDE5 in myoid cells was confirmed by Western blot analysis and immunohistochemistry performed on highly purified cell fractions, obtained from 16-day-old rats. The expression of PDE5 in these somatic cells of rat testis is discussed in view of the roles played by cGMP signal transduction pathways in the mammalian male reproductive function.

The Role of PDE5 Inhibitors in the Treatment of Testicular Dysfunction

“…cGMP-hydrolyzing-PDE5 has been localized in peritubular myoid cells of the rat (Scipioni et al, 2005). In another study by Coskran et al, (2006) PDE10A-immunoreactivity was detected in seminiferous tubules and epididymal spermatozoa of dog and cynomolgus macaque and in the testis of mouse, with no detectable immunoreactivity in testes or epididymes of rat or human (Coskran et al, 2006).…”

“…Scipioni et al, (2005) have reported that there is expression of PDE5 in Leydig cells and peritubular cells both in prepuberal and in adult rat testis. This gives additional strength to the idea that in mammalian testis cGMP-mediated processes influence not only the vessel dilatation but also the testosterone synthesis by Leydig cells and the transfer of spermatozoa, through the relaxation of peritubular lamina propria cells (Scipioni et al, 2005). In peritubular myoid cells, in particular, besides regulating contractility, cGMP modulation by PDE5 might affect the secretion of a number of substances, including extracellular matrix components (fibronectin, type I and IV collagens, proteoglycans) and growth factors (PModS, TGF beta, IGF-I, activin-A).…”

“…Since sGC has been found to be present in peritubular myofibroblasts, production of CO by HO-1 in the adluminal parts of Sertoli cells may trigger cGMP accumulation in peritubular lamina propria cells suggesting separation of the site of production and action of CO thereby mediating relaxation of myofibroblasts (Middendorff et al, 1997). Scipioni et al, (2005) have reported that there is expression of PDE5 in Leydig cells and peritubular cells both in prepuberal and in adult rat testis. This gives additional strength to the idea that in mammalian testis cGMP-mediated processes influence not only the vessel dilatation but also the testosterone synthesis by Leydig cells and the transfer of spermatozoa, through the relaxation of peritubular lamina propria cells (Scipioni et al, 2005).…”

“…Published data on PDE expression in testis until now is primarily restricted to cAMP-hydrolyzing PDEs, such as PDE1C, PDE4A, PDE4C, PDE7B and PDE8A and their localization to male germ cells and spermatozoa (Bender & Beavo, 2006). With respect to cGMP pathways, transcripts of the cGMPhydrolyzing PDE10 have been found in the human testis and cGMPhydrolyzing PDE5 has been recently localized to peritubular myoid cells of the rat (Scipioni et al, 2005).…”

Oral phosphodiesterase-5 inhibitors and sperm functions

“…12 Data on PDE expression in testis are restricted predominantly to cAMP-hydrolyzing PDEs, such as PDE1C, PDE4A, PDE4C, PDE7B and PDE8A, and also provide useful information about PDE localization in male germ cells and spermatozoa. 13 Transcripts of PDE10 were found in the human testis, 14 cGMP-hydrolyzing PDE5 was localized in peritubular myoid cells of rats 15 and regulation of epididymal duct contractility by PDE3 has been suggested. 16 PDE11, the latest isoform of the PDE family that raised interest recently, 17 contains one gene, PDE11A, with four splice variants (PDE11A1-4).…”