Effect of ET receptor antagonists on procollagen α1(I) mRNA expression of 1st passage HSC. Cells were stimulated with 10-6 M ET-1 in the absence or presence of the ETAR antagonist BQ123 (10-6 M) or the ETBR antagonist BQ788 (10-6 M) for 48 hours. The mRNA levels were determined by real time quantitative PCR. Results are given as mean ± SD (n = 4). **p < 0.01 vs control, ## p < 0.01 vs ET-1 (10-6 M).