Hematopoietic stem cells (HSC) are multipotent cells that reside in the bone marrow and replenish all adult hematopoietic lineages throughoutthe lifetime. In this study, we analyzed the expression of receptors of P2Y10, purinergic receptor families in murine hematopoietic stem cells, hematopoietic progenitor cells. In addition, the biological activity of P2Y10 was investigated with B lymphocyte cell line, Ba/F3 in effect to cell growth and cell cycle. From the analysis of expression in hematopoieticstem cell. and progenitor with RT-PCR, P2Y10 was strongly expressed in murine hematopoieticstem cells (c-kit+ Sca-l+ Lin-) and progenitor cell population, such as c-kit- Sca-l+ Lin-, c-kit+ Sca-l- Lin- and c-kit- Sca-l- Lin-. To investigate the biological effects by P2Y10, retroviral vector from subcloned murine P2Y10 cDNA was used fur gene introduction into Ba/F3 cells, and stable transfectant cells were obtained by flow cytometry sorting. In cell proliferation assay, the proliferation ability of P2Y10 receptor gene­transfected cells was strongly inhibited, and the cell cycle was arrested at G1 phase. These result suggest that the P2Y10 may be involved the biological activity in hematopoietic stem cells and immature B lymphocytes.