title: Hepatocyte growth factor-modulated rat Leydig cell functions.
abstract: Hepatocyte growth factor (HGF) regulates many cellular functions acting through c-Met, its specific tyrosine kinase receptor. We previously reported that in prepuberal rats HGF is secreted by the peritubular myoid cells during the entire postnatal testicular development and by the Sertoli cells only at puberty. We have also demonstrated that germ cells at different stages of development express c-Met and that HGF modulates germ cell proliferation and apoptosis. In the present article, we extend our study to the interstitial compartment of the testis and demonstrate that the c-Met protein is present on Leydig cells. The receptor is functionally active as demonstrated by the detected effects of HGF. We report in this article that HGF significantly increases the amount of testosterone secreted by the Leydig cells and decreases the number of Leydig cells undergoing apoptosis. The antiapoptotic effect of HGF is mediated by caspase-3 activity because the amount of the active fragment of the enzyme is decreased in Leydig cells cultured in the presence of HGF. However, treatment with the growth factor does not modify the expression levels of caspase-3 mRNA. These data indicate that HGF regulates the functional activities of Leydig cells. Interestingly, the steroidogenetic activity of the cells is increased by HGF in cultured explants of testicular tissues as well as the antiapoptotic effect of HGF. Therefore, our data indicate that HGF has a crucial role in the regulation of male fertility.
authors.affiliation: Dip. Istologia ed Embriologia Medica, Via A. Scarpa 14, Rome, Italy.
authors.forename: Jessica
authors.initials: J
authors.lastname: Del Bravo
authors.forename: Angela
authors.initials: A
authors.lastname: Catizone
authors.forename: Giulia
authors.initials: G
authors.lastname: Ricci
authors.forename: Michela
authors.initials: M
authors.lastname: Galdieri
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D018929:Cell Culture Techniques; D003470:Culture Media; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D020287:In Situ Nick-End Labeling; D007985:Leydig Cells / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009924:Organ Culture Techniques; D019859:Proto-Oncogene Proteins c-met / Q000187:drug effects / Q000235:genetics; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013737:Testis / Q000187:drug effects / Q000502:physiology; D013739:Testosterone / Q000378:metabolism
chemical_list: D003470:Culture Media; D013739:Testosterone; D012313:RNA; D017228:Hepatocyte Growth Factor; D019859:Proto-Oncogene Proteins c-met