Left ventricular hypertrophy was present as evidenced by increased heart and LV to body weight ratios, upregulation of ANP gene expression (Table 1) and by increased cardiomyocyte cross-sectional area (Fig 4), although the cardiomyocyte cross-sectional area may be interpreted with caution as the hearts were not perfusion-fixed in end-diastole. Here, NPPA is linked to left ventricular hypertrophy.