AGT and fibrosis: By assessing differential effects of Ang II on cardiac cell proliferation and intramyocardial perivascular fibrosis in vivo, infusion of Ang II into rats caused an increase in collagen deposition surrounding intracoronary blood vessels and an extension of collagen into the myocardial interstitium, with an increase in cell proliferation of adventitial and interstitial fibroblasts [81].