Lysophosphatidic acid (LPA) interacts with G protein-coupled transmembrane LPA receptors (LPA receptors; LPA(1)-LPA(6)). Recently, we demonstrated that each LPA receptor acts as a positive or negative regulator of cell migration ability. It is known that estrogens indicate a variety of biological functions, including cell motility. In the present study, to assess whether LPA signaling is involved in cell motile activity stimulated by estrogens, we measured cell motile activity and LPA receptor expressions of rat liver epithelial WB-F344 cells treated with 17 beta-estradiol (E-2), ethinyl estradiol (EE) and diethylstilbestrol (DES) at concentrations of 0.1 and 1.0 mu M for 48 h. The cell motility of E-2 and EE treated cells was significantly higher than that of untreated cells. By contrast, DES markedly inhibited cell motile activity. Using quantitative real time RT-PCR analysis, Lpar1 and Lpar3 expressions in E-2 treated cells were significantly higher than those in untreated cells. In EE treated cells, Lpar3 expression was markedly elevated, whereas Lpar1 expression was decreased. On the other hand, Lpar1 expression was significantly increased in DES treated cells. Interestingly, the effects of E-2, EE and DES on cell motility were suppressed by Lpar1 or Lpar3 knockdown. These results suggest that the different induction of LPA receptors by estrogens may regulate cell motile activity of WB-F344 cells. (C) 2012 Elsevier Inc. All rights reserved.