Expression analysis of gnrh1 and gnrhr1 in spermatogenic cells of rat

Hypothalamic Gonadotropin Releasing Hormone (GnRH), via GnRH receptor (GnRHR), is the main actor in the control of reproduction, in that it induces the biosynthesis and the release of pituitary gonadotropins, which in turn promote steroidogenesis and gametogenesis in both sexes. Extrabrain functions of GnRH have been extensively described in the past decades and, in males, local GnRH activity promotes the progression of spermatogenesis and sperm functions at several levels. The canonical localization of Gnrh1 and Gnrhr1 mRNA is Sertoli and Leydig cells, respectively, but ligand and receptor are also expressed in germ cells. Here, we analysed the expression rate of Gnrh1 and Gnrhr1 in rat testis (180 days old) by quantitative real-time PCR (qPCR) and by in situ hybridization we localized Gnrh1 and Gnrhr1 mRNA in different spermatogenic cells of adult animals. Our data confirm the testicular expression of Gnrh1 and of Gnrhr1 in somatic cells and provide evidence that their expression in the germinal compartment is restricted to haploid cells. In addition, not only Sertoli cells connected to spermatids in the last steps of maturation but also Leydig and peritubular myoid cells express Gnrh1.

Endocannabinoids and endovanilloids: a possible balance in the regulation of the testicular GnRH signalling

Reproductive functions are regulated both at central (brain) and gonadal levels. In this respect, the endocannabinoid system (eCS) has a very influential role. Interestingly, the characterization of eCS has taken many advantages from the usage of animal models different from mammals. Therefore, this review is oriented to summarize the main pieces of evidence regarding eCS coming from the anuran amphibian Rana esculenta, with particular interest to the morphofunctional relationship between eCS and gonadotropin releasing hormone (GnRH). Furthermore, a novel role for endovanilloids in the regulation of a testicular GnRH system will be also discussed.

Effect of progesterone and oestradiol on sperm-zona binding and acrosome reaction in bovine spermatozoa after thawing

This study was conducted assess spermatozoa binding capacity to the oocyte in the presence of 0.1 or 0.5 microg/ml progesterone (P4) or a combination of 0.5 microg/ml P4 with 0.1 microg/ml oestradiol (OE). The number of oocyte-bound spermatozoa in the presence of progesterone was significantly higher (p < 0.05 to p < 0.001) when compared with the control samples, that were incubated in the absence of P4. Spermatozoa binding to the zona pellucida (ZP) of the oocyte were concentration-dependent - significantly higher numbers of spermatozoa were bound in the presence of 0.5 microg/ml P4, when compared with that of 0.1 microg/ml P4. Oestradiol at 0.1 microg/ml concentration used impaired the effect of progesterone-mediated sperm-oocyte binding. The incidences of acrosome-reacted (AR) spermatozoa bound to the ZP - following 0, 60, 120 and 180 min. incubation in the presence and absence of 1 microg/ml progesterone was also assessed. Only at 180 min of incubation a higher (p < 0.001) incidence of the AR-spermatozoa was found in sperm-ZP complexes incubated in the presence or absence of progesterone, being 56.5 +/- 11.1 and 43.2 +/- 8.8 % respectively. In conclusion, progesterone enhances the sperm-ZP binding capacity. Progesterone affects the incidences of AR on zona-bound spermatozoa only after prolonged co-culture.