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Tonin in rat heart with experimental hypertrophy
Julio Cesar Borges1, José Antônio Silva, Maria Aparecida Gomes
1Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Brazil. jlpesq@icb.ufmg.br
American Journal of Physiology. Heart and Circulatory Physiology
|January 25, 2003
Summary
This study reveals that tonin, an enzyme, is upregulated in rat atria during isoproterenol-induced heart hypertrophy, suggesting its potential role in this condition.
Area of Science:
- Cardiovascular Physiology
- Enzymology
- Molecular Biology
Background:
- Cardiac hypertrophy is a significant risk factor for heart failure.
- The renin-angiotensin system (RAS) plays a crucial role in cardiovascular regulation.
- The role of tonin in cardiac hypertrophy remains incompletely understood.
Purpose of the Study:
- To investigate the expression and activity of tonin in the rat heart during isoproterenol-induced hypertrophy.
- To assess the expression of other key RAS components, including renin, angiotensin-converting enzyme (ACE), and angiotensinogen (AG).
Main Methods:
- Wistar rats were subjected to isoproterenol treatment for 7 days to induce cardiac hypertrophy.
- Tonin-specific activity was measured using biochemical assays.
- Expression levels of renin, ACE, and AG were determined using molecular techniques (mRNA detection).
Main Results:
- Baseline tonin activity was significantly higher in the atrium compared to the ventricles.
- Isoproterenol treatment led to a twofold increase in tonin activity in the atrium but not in the ventricles.
- Renin expression was undetectable; ACE expression remained unchanged; AG expression increased in the hypertrophied atrium.
Conclusions:
- Tonin expression and activity are increased in the atrium during isoproterenol-induced cardiac hypertrophy in rats.
- These findings suggest that tonin may play a specific role in the development of cardiac hypertrophy, particularly in the atrial tissue.