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Isoproterenol induced changes in myocardial nucleic acids
Research Communications in Chemical Pathology and Pharmacology
|June 1, 1983
Summary
Daily isoproterenol injections caused significant heart weight increase and elevated RNA levels. Despite cardiac hypertrophy, heart pressures and coronary flow remained stable, with a slight increase in muscle contractility.
Area of Science:
- Cardiovascular Physiology
- Molecular Cardiology
Background:
- Isoproterenol is a non-selective beta-adrenergic agonist.
- Cardiac hypertrophy can be induced by various stimuli.
Purpose of the Study:
- To investigate the effects of daily isoproterenol administration on cardiac structure and function.
- To assess changes in myocardial RNA and DNA content during induced cardiac hypertrophy.
Main Methods:
- Rats were administered daily subcutaneous injections of isoproterenol.
- Heart weight, ventricular RNA and DNA concentrations, ventricular pressures, coronary flow, and muscle contractility were measured.
Main Results:
- A 42% increase in heart weight was observed after 4 days of isoproterenol therapy.
- Ventricular RNA concentration significantly increased within 24 hours.
- Myocardial DNA significantly increased after 8 days of treatment.
- Ventricular systolic and diastolic pressures, and coronary flow were not diminished.
- A slight increase in muscle contractility was noted (P < .05).
Conclusions:
- Daily isoproterenol injections induce rapid cardiac hypertrophy.
- The hypertrophied heart maintains normal pressures and coronary flow.
- Isoproterenol-induced cardiac hypertrophy is associated with increased myocardial RNA and DNA synthesis.