HEMODYNAMIC-EFFECTS OF SCATTER FACTOR IN CONSCIOUS RATS

Scatter factor (SF), also known as hepatocyte growth factor, is a pote nt mitogen that has been suggested to exhibit greater efficacy than va scular endothelial growth factor (VEGF) in rabbits with hindlimb ische mia. Our study examined the effects of SF on cardiovascular hemodynami cs and compared the responses to VEGF. Hemodynamic parameters were mon itored before and after administration of SF or VEGF in conscious, ins trumented rats. Intravenous injection of SF-produced a dose-related re duction in mean arterial pressure (MAP) and increase in heart rate (HR ). These responses were significantly attenuated by pretreatment with N-omega-nitro-L-arginine methyl ester, a nitric oxide (NO) synthase in hibitor, suggesting the depressor effect of SF may be mediated by NO. SF (250 mu g/kg) reduced stroke volume and cardiac output, but did not affect the maximal first derivation of left ventricular pressure (dP/ dt), suggesting that the reduction in cardiac output is caused by decr eased stroke volume that probably results from a reduction in venous r eturn. Compared with SF, VEGF produced greater hypotensive and tachyca rdic responses and greater reductions in stroke volume and cardiac out put, indicating that SF has fewer side effects on hemodynamics. Althou gh both growth factors might reduce venous return, SF decreased hemato crit presumably through venodilation, whereas VEGF increased hematocri t as a result of vascular hyperpermeability.