Comparison of isoproterenol and dobutamine in the induction of cardiac hypertrophy and fibrosis.

Isoproterenol (Iso) was a clinical therapeutic that is now used as a research means for the induction of cardiac hypertrophy. Currently, dobutamine (Dob) has replaced Iso as the preferred inotropic beta-adrenergic agent to wean patients from cardiopulmonary bypass and to sustain adequate cardiac function during the postoperative period. We sought to compare the cardiac structural and functional effects of long-term administration (7days) of Iso with Dob at a dose of 40microg/mouse/day in 12-week-old C57BL/6 female mice. Cardiac function was determined with transthoracic echo cardiography (ECHO) 24 hours after the last dose. Cardiac wet weights increased 33% and 24% in the Iso and Dob groups compared with controls (p < 0.05). Dob and Iso significantly increased cardiac fibrosis and decreased cardiac function with chronic administration. Administration also resulted in increased left atrial size, suggesting that both Dob and Iso decreased LV compliance, but did not induce heart failure. In conclusion, chronic administration of Dob may have a detrimental effect on cardiac structure and function.