Figure 5  .

Effect of endothelin 1 (ET-1) and/or endothelin receptor antagonists on HT29 cell growth. Cells were grown for 48 or 72 hours in the presence of 10⁻⁹ M ET-1 and/or ET_A receptor antagonist BQ123 or BQ610, or ET_B receptor antagonist BQ788, all at 100 nM. Cell growth was measured using the methylene blue assay and read as absorbance (equivalent to cell numbers) at 650 nm. Results are shown as mean (SD). Cell numbers were significantly higher in the ET-1 group compared with control cells (*p<0.05, Student's t-test); cell numbers from groups treated with both ET-1 and ET_A antagonists were similar to control levels, and were significantly lower than in the ET-1 group (†p<0.05, Student's t test).