ADRENOMEDULLIN - CHANGES IN CIRCULATING AND CARDIAC TISSUE CONCENTRATION IN DAHL SALT-SENSITIVE RATS ON A HIGH-SALT DIET

Adrenomedullin (AM), a novel hypotensive peptide, is suggested to be i nvolved in defense mechanisms against hypertension, however, the detai l mechanisms have not been clarified. To elucidate whether AM synthesi s would be altered in a salt dependent hypertension, we have investiga ted the AM concentration and AM messenger RNA (mRNA) level in tissues of Dahl salt-sensitive rats on either low- or high-salt intake. The AM concentration in cardiac ventricle of the high-salt group was signifi cantly higher than that of the low-salt group. The plasma AM concentra tion was also significantly higher in the high-salt group than in the low-salt group. Furthermore, the plasma AM concentration correlated we ll with the weight of left ventricle. RNA blot analysis revealed that the AM mRNA level in cardiac ventricle of the high-salt group was high er than that of the low-salt group. These results suggest that AM part icipates in the pathophysiology of salt dependent hypertension and pla ys a role in cardiac hypertrophy.