Atrial natriuretic peptide messenger RNA and peptide in rats with aortic valve insufficiency

To investigate ANP gene expression in diseased hearts of animals without genetic defects, immunoreactive ANP (IR-ANP) and ANP mRNA were measured in a rat with aortic valve insufficiency (AI), which was produced by puncturing one of the aortic valve leaflets with a plastic rod. Plasma IR-ANP concentration was higher in AI rats than in sham rats (p less than 0.05). Decreased atrial concentration of IR-ANP (p less than 0.05) and unchanged atrial ANP mRNA concentration were shown in AI rats. The ventricular concentrations of IR-ANP and ANP mRNA in AI rats were 5.4 and 2.4 times higher than those in sham rats (p less than 0.05, respectively). These results demonstrate that gene expression of ventricular ANP is markedly increased in AI rats while that of atrial ANP is not changed.