title: Efficiency and capacity of protein synthesis are increased in pressure overload cardiac hypertrophy.
abstract: We measured the rate of protein synthesis and total RNA content in the right ventricle (RV) at day 2 and day 4 after pulmonary artery constriction to determine the contributions of changes in capacity and efficiency of in vivo protein synthesis to pressure overload (PO) cardiac hypertrophy. A significant increase in the proportion of RV weight to total heart weight was observed at day 2 and day 4 when compared with untreated controls. The rate of protein synthesis was significantly higher at day 2 post-PO (0.31 +/- 0.06 day-1 or 30 +/- 5 mg.g RV-1.day-1, means +/- SD, P less than 0.05) as well as at day 4 (0.25 +/- 0.05 day-1 or 28 +/- 9 mg.g RV-1.day-1, P less than 0.05) than for untreated rabbits (0.15 +/- 0.03 day-1 or 17 +/- 4 mg.g RV-1.day-1). RNA content was significantly higher at day 2 (1.47 +/- 0.17 mg/g RV, P less than 0.05) than in controls (1.16 +/- 0.14 mg/g RV), whereas there was a slight but nonsignificant increase at day 4 (1.36 +/- 0.21 mg/g RV, P less than 0.1). The efficiency of protein synthesis (synthesis/RNA) per gram RV was significantly increased both at day 2 (20.5 +/- 2.2 g protein.g RNA-1.day-1, P less than 0.05) and day 4 (19.8 +/- 3.5 g protein.g RNA-1.day-1, P less than 0.05) compared with control (14.6 +/- 2.3 g protein.g RNA-1.day-1). The increase in efficiency appeared to be caused by pressure overload itself based on a comparison of 0-4 day data vs. data obtained from sham animals (P less than 0.05).
authors: Department of Physiology and Biophysics, University of Vermont, Burlington 05405.
authors: R
authors: R
authors: Nagai
authors: R B
authors: RB
authors: Low
authors: W S
authors: WS
authors: Stirewalt
authors: N R
authors: NR
authors: Alpert
authors: R Z
authors: RZ
authors: Litten
mesh_terms: D000818:Animals; D006332:Cardiomegaly / Q000378:metabolism*; D006321:Heart / Q000033:anatomy & histology; D006352:Heart Ventricles / Q000378:metabolism; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009929:Organ Size; D014176:Protein Biosynthesis; D011651:Pulmonary Artery / Q000502:physiology; D012313:RNA / Q000378:metabolism; D011817:Rabbits; D012016:Reference Values; D014316:Tritium
chemical_list: D014316:Tritium; D012313:RNA; D007930:Leucine