Hepatocyte growth factor (HGF) receptor expression and role of HGF during embryonic mouse testis development

The hepatocyte growth factor (HGF) receptor, c-met, transduces the HGF mult iple biological activities. During embryonic development the system HGF/c-m et regulates the morphogenesis of different organs and tissues. In this stu dy we examined c-met gene expression during mouse testis development and, b y means of Northern blot and in situ hybridization, we report the receptor expression pattern. C-met expression is not detectable in male genital ridg es isolated from embryos at 11.5 days postcoitum (dpc). In testes isolated from 12.5 and 13.5 dpc, c-met expression is detectable and essentially loca lized in the developing cords. Male genital ducts do not express c-met at t he reported ages, whereas female ducts appear c-met positive. Moreover, we report that HGE is able to induce testicular morphogenesis in vitro. Male g enital ridges isolated from embryos at 11.5 dpc are morphologically nonorga nized. Culturing 11.5 dpc urogenital ridges in the presence of HGF we obtai ned testis organization and testicular cord formation. Our data demonstrate that c-met is expressed during the beginning period of testis differentiat ion and that HGF is able to support testicular differentiation in vitro. Al l these data indicate that this growth factor, besides its role as mitogeni c factor, plays a fundamental role during testicular cord formation probabl y inducing cell migration and/or cell differentiation. (C) 1999 Academic Pr ess.