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Mitochondrial protein synthesis during thyroxine-induced cardiac hypertrophy
1Department of Biological Chemistry and Structure, University of Health Sciences/Chicago Medical School, North Chicago, Illinois 60064.
The American Journal of Physiology
|March 1, 1990
Summary
Thyroid hormone (T3) injections stimulate cardiac hypertrophy and protein synthesis in rats. Mitochondrial protein synthesis rates increase significantly during T3-thyroxine-induced cardiac enlargement.
Area of Science:
- Physiology
- Biochemistry
- Endocrinology
Background:
- Cardiac hypertrophy can be induced by thyroid hormones like thyroxine.
- Understanding protein synthesis regulation is crucial for cardiac health.
Purpose of the Study:
- To investigate the effects of T3-thyroxine-induced cardiac hypertrophy on mitochondrial and total protein synthesis rates.
- To compare these synthesis rates with cardiac enlargement.
Main Methods:
- Rats were injected with T3-thyroxine to induce cardiac hypertrophy.
- Protein synthesis rates (cytoplasmic and mitochondrial) were measured in isolated perfused hearts.
- Rates were assessed over a 9-day period.
Main Results:
- T3-thyroxine induced a 25% increase in ventricular growth.
- Cytoplasmic synthesis of mitochondrial and total proteins peaked at 155% and 146% of control, respectively, after 3 days.
- Mitochondrial protein synthesis rates showed dramatic stimulation.
Conclusions:
- T3-thyroxine significantly impacts cardiac protein synthesis during hypertrophy.
- Both cytoplasmic and mitochondrial systems are affected, with distinct temporal patterns.