Although many lines of evidence have suggested that angiotensin II (Ang II) plays an important role in development of cardiac hypertrophy, the mechanism by which Ang II increases protein synthesis in cardiac myocytes remains unclear. It has been reported that the phosphorylation of $6 protein in 40 S ribosome is correlated to the efficiency of protein synthesis. In the present study, we have examined whether Ang II activates p70 $6 kinase (p70S6g), which has been reported to phosphorylate $6 protein.