We evaluated the effects of TxA2 analog (STA2), TxA2 inhibitor (OKY-046) and PGI2 analog (OP-2507) on the dog hepatocytes isolated after 84% hepatectomy. Cells isolated after 6 h following hepatectomy were cultured with normal medium (control) and in the presence of STA2. OKY-046 and OP-2507, respectively. In the presence of 0.1 nM STA2, cytosolic free CA2+ as well as LDH and bleb formation was significantly higher, and intracellular cAMP was significantly lower than those in the control, respectively. In the presence of 1 nM OP-2507, these changes were significantly inhibited. OKY-046 had no direct effect on hepatocytes. Present data shows the cytotoxic effect of TXA2 analog and the cytoprotective effect of PGI2 analog on hepatocytes.