Different from the blockade of AT1 receptor by losartan, activation of AT2 or Mas receptors by C21 and Ang 1-7 treatment, respectively, did not reduce the marked increase of blood pressure caused by Ang II administration (Table 1 and Table 2), but were nevertheless as effective as losartan in the prevention of myocardial fibrosis and hypertrophy. The gene discussed is AGTR1; the disease is Myocardial fibrosis.