|
|
||||||||
Departments of Cellular and Molecular Physiology and Surgery, Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033
The purpose
of the present study was to examine potential mechanisms for the known
inhibitory effect of acute alcohol exposure on myocardial protein
synthesis. Rats were injected intraperitoneally with either ethanol (75 mmol/kg) or saline, and protein synthesis was measured in vivo 2.5 h thereafter by use of the flooding-dose L-[3H]phenylalanine technique. Rates of
myocardial protein synthesis and translational efficiency in
alcohol-treated rats were decreased compared with control values. Free
(nonpolysome bound) 40S and 60S ribosomal subunits were increased 50%
after alcohol treatment, indicating an impaired peptide-chain
initiation. To identify mechanisms responsible for this impairment,
several eukaryotic initiation factors (eIF) were analyzed. Acute
alcohol intoxication did not significantly alter the myocardial content
of eIF2
or eIF2B
, the extent of eIF2
phosphorylation, or the
activity of eIF2B. Acute alcohol exposure increased the binding of
4E-binding protein 1 (4E-BP1) to eIF4E (55%), diminished the amount of
eIF4E bound to eIF4G (70%), reduced the amount of 4E-BP1 in the
phosphorylated
-form (40%), and decreased the phosphorylation of
p70S6 kinase and the ribosomal protein S6. There was no significant
difference in either the plasma insulin-like growth factor (IGF) I
concentration (total or free) or expression of IGF-I or IGF-II mRNA in
heart between the two groups. These data suggest that the acute
alcohol-induced impairment in myocardial protein synthesis results, in
part, from an inhibition in peptide-chain initiation, which is
associated with marked changes in eIF4E availability and p70S6 kinase
phosphorylation but is independent of changes in the eIF2/2B system and IGFs.
cardiomyopathy; peptide-chain initiation; eukaryotic initiation factor 4E; 4E-binding protein 1; eukaryotic initiation factor 4G
This article has been cited by other articles:
![]() |
ThomasC. Vary Oral Leucine Enhances Myocardial Protein Synthesis in Rats Acutely Administered Ethanol J. Nutr., August 1, 2009; 139(8): 1439 - 1444. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. D. Bird and E. J. Kovacs Organ-specific inflammation following acute ethanol and burn injury J. Leukoc. Biol., September 1, 2008; 84(3): 607 - 613. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. C. Vary, S. R. Kimball, and A. Sumner Sex-dependent differences in the regulation of myocardial protein synthesis following long-term ethanol consumption Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2007; 292(2): R778 - R787. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. C. Vary, G. Deiter, and S. A. Goodman Acute alcohol intoxication enhances myocardial eIF4G phosphorylation despite reducing mTOR signaling Am J Physiol Heart Circ Physiol, January 1, 2005; 288(1): H121 - H128. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. H. Lang, R. A. Frost, and T. C. Vary Thermal injury impairs cardiac protein synthesis and is associated with alterations in translation initiation Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2004; 286(4): R740 - R750. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. J. Lynch, B. J. Patson, J. Anthony, A. Vaval, L. S. Jefferson, and T. C. Vary Leucine is a direct-acting nutrient signal that regulates protein synthesis in adipose tissue Am J Physiol Endocrinol Metab, September 1, 2002; 283(3): E503 - E513. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. C. Vary, C. J. Lynch, and C. H. Lang Effects of chronic alcohol consumption on regulation of myocardial protein synthesis Am J Physiol Heart Circ Physiol, September 1, 2001; 281(3): H1242 - H1251. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |