HSC apoptosis. A :Apoptotic rate of 1st and 4th passage HSC induced by different concentrations of Fas-ligand. Apoptotic rate of HSC was measured after HSC were incubated in DMEM with 0.125% FCS containing Fas-ligand at different concentrations for 24 hours. Results are given as mean ± SD (n = 4). **: p < 0.01 vs control. B :Effect of ET-1 and ET receptor antagonists on Fas-induced apoptosis of 1st and 4th passage HSC. HSC in DMEM containing 0.125% FCS were incubated with ET -1 alone at 10-8 M or 10-6 M with or without Fas-ligand (50 ng/ml), or with ET-1 (10-6 M), FasL and the ETAR antagonist BQ123 or the ETBR antagonist BQ788 (both at 10-6 M). Results are given as mean ± SD (n = 8).