Key result
Atrial protein-synthesis rates and RNA contents reach ~2-fold higher levels than ventricular muscle in rats.
Why the study?
Differences in protein synthesis rates and RNA contents between rat heart ventricular and atrial muscle during growth were not fully characterized.
This preclinical study demonstrates that while atrial protein synthesis rates and RNA contents are double those of ventricles in rats, the overall efficiency of protein synthesis is similar across both compartments.
Rat atrial-ventricular protein synthesis differences provide baseline data; leaves open human disease relevance and clinical translation.
The rates of protein synthesis in perfused rat heart ventricular or atrial muscle were measured by incorporation of [U-14C]phenylalanine in the presence of the remaining plasma amino acids. Atrial protein-synthesis rates were about twice the ventricular rates. Atrial RNA contents were also about twice the ventricular contents. Thus the efficiencies of protein synthesis (protein-synthesis rate/RNA) in the two compartments were similar. There were marked differences in ventricular and atrial RNA contents during the course of rat growth. Atrial RNA content was always greater than ventricular content and declined more slowly during growth, producing a 2-fold change in atrial/ventricular RNA-content ratio between the 88 g and 370 g rat groups.
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Smith et al. (1983) studied this question. Atrial muscle vs. Ventricular muscle was evaluated on Rates of protein synthesis and RNA contents. Atrial protein-synthesis rates and RNA contents were approximately twice those of ventricular muscle in rats, resulting in similar protein synthesis efficiencies between the two compartments.
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