[Geldanamycin administration reduces the number of HSP86-positive germ cells in the mouse embryo: preliminary results].

5 mg of Geldanamycin, an inhibitor of stress protein HSP86 which express on mammalian germ cells, were administered to E8 pregnant mice. E17 embryos were removed, and a quantitative analysis of HSP90-immunoreactive cells in the gonad was performed, in comparison to control embryos. First, we observed that the number of germ cells is lower in male than in female embryos, as well in control and experimental embryos. External features of experimental and control embryos did not display any difference. Embryos exposed to geldanamycin exhibit a significant decrease of immunoreactive germ cells. In two embryos, we observed a group of ectopic immunoreactive cells in the pelvic area. We conclude that geldanamycin inhibits germ cells migration, and suggest that this inhibition can lead to ectopic germ cell populations, similar to teratomas.