NAD treatment blocks the agonist-induced cardiac hypertrophy in vivo. A, heart weight (HW)/body weight (BW) ratio of different groups of mice (vehicle, NAD, Ang-II, or Ang-II plus NAD-treated mice, as well as mice subjected to swim exercise). B, top panel, hematoxylin- and eosin-stained sections of whole hearts of different groups; middle panel, sections of hearts stained with Masson's trichrome to detect fibrosis (blue); bottom panel, heart sections stained with wheat germ agglutinin to demarcate cell boundaries. C and D, quantification of cardiac fibrosis and the myocyte cross-sectional area in different groups of mice. E and F, Anf, brain natiuretic peptide (BNP), β-myosin heavy chain (MHC), and Collagen-α mRNA levels in the heart samples of Ang-II alone or Ang-II plus NAD-treated mice. G and H, quantification of NAD and ATP contents in the heart lysate of different groups of mice as in panel A. Values are mean ± S.E. of five to eight experiments.