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Altered cardiac polyamine biosynthesis in spontaneously hypertensive rats
The American Journal of Physiology
|August 1, 1987
Summary
Polyamines, like spermidine, are crucial for heart growth. In hypertensive rats, elevated spermidine accompanies heart enlargement, but this can reverse independently of polyamine levels.
Area of Science:
- Cardiovascular Physiology
- Biochemistry
- Molecular Biology
Background:
- Polyamines are essential for cell growth and differentiation.
- Their role in myocardial growth, particularly in the context of cardiac hypertrophy, requires further elucidation.
Purpose of the Study:
- To investigate the involvement of polyamine biosynthesis in myocardial growth.
- To analyze polyamine levels and ornithine decarboxylase (ODC) activity in developing and hypertrophied rat hearts.
Main Methods:
- Measured ODC activity and polyamine levels (spermidine, spermine, putrescine) in Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rat hearts from birth to 30 weeks.
- Assessed the effects of minoxidil and methyldopa treatments on polyamine content and cardiac mass in adult rats.
Main Results:
- ODC activity decreased with age in developing hearts.
- SHR hearts showed elevated spermidine and reduced spermine, leading to higher spermidine/spermine ratios, indicative of growth.
- Minoxidil increased heart weight and polyamine content; methyldopa increased spermidine despite reducing heart mass.
Conclusions:
- Ventricular hypertrophy in SHR is associated with enhanced spermidine synthesis and accumulation.
- Myocardial spermidine content can increase during regression of cardiac hypertrophy, suggesting independent mechanisms.