Many researches to elucidate the mechanism of gravity sense and its response in the living cells have been advanced. But it has not yet identified that key molecule or signal transduction pathway related to gravity sense and its response. Our goal is to clarify the mechanism of gravity sense, especially the point of gravity sense. First, we have investigated about differences of gene expression level (mRNA) of the endothelial cells cultivated under vector-averaged gravity condition (Clinorotation). The Differential Display pattern showed that expression level of several genes had changed between clinorotated condition and control. The homologues of these fragments were searched on the BLAST database. From BLAST database searching results, GEF and cell adhesion protein effected by clinorotaion. Moreover, morphological and immunological techniques data showed that the cytoskeletal formation of actin, tubulin, etc. or localization in cell of Rho protein were changed. These results suggested that signal transduction pathway through Rho played an important role in the gravity sense mechanism of endothelial cells. Furthermore, we are going to investigate relation between gene expression and morphological data.