|
|
||||||||
Departments of Cellular and Molecular Physiology and Surgery, Pennsylvania State College of Medicine, Hershey, Pennsylvania 17033
The present study
examined potential mechanisms for the inhibition of protein synthesis
in skeletal muscle after chronic alcohol consumption. Rats were
maintained on an alcohol-containing diet for 14 wk; control animals
were pair fed. Alcohol-induced myopathy was confirmed by a reduction in
lean body mass as well as a decrease in the weight of the gastrocnemius
and psoas muscles normalized for tibial length. No alcohol-induced
decrease in total RNA content (an estimate of ribosomal RNA) was
detected in any muscle examined, suggesting that alcohol reduced
translational efficiency but not the capacity for protein synthesis. To
identify mechanisms responsible for regulating translational
efficiency, we analyzed several eukaryotic initiation factors (eIF).
There was no difference in the muscle content of either total eIF2
or the amount of eIF2
in the phosphorylated form between alcohol-fed
and control rats. Similarly, the relative amount of eIF2B
in muscle
was also not different. In contrast, alcohol decreased eIF2B activity
in psoas (fast-twitch) but not in soleus or heart (slow-twitch)
muscles. Alcohol feeding also dramatically influenced the distribution
of eIF4E in the gastrocnemius (fast-twitch) muscle. Compared with
control values, muscle from alcohol-fed rats demonstrated
1) an increased binding of the
translational repressor 4E-binding protein 1 (4E-BP1) with eIF4E,
2) a decrease in the phosphorylated
-form of 4E-BP1, and 3) a
decrease in eIF4G associated with eIF4E. In summary, these data suggest
that chronic alcohol consumption impairs translation initiation in
muscle by altering multiple regulatory sites, including eIF2B activity
and eIF4E availability.
ethanol; peptide-chain initiation; translation initiation; eukaryotic initiation factors 2, 4E, and 4G; 4E-binding protein 1; adenosine 5'-triphosphate; rats
This article has been cited by other articles:
![]() |
A. M. Karinch, J. H. Martin, and T. C. Vary Acute and chronic ethanol consumption differentially impact pathways limiting hepatic protein synthesis Am J Physiol Endocrinol Metab, July 1, 2008; 295(1): E3 - E9. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. C. Vary, R. A. Frost, and C. H. Lang Acute alcohol intoxication increases atrogin-1 and MuRF1 mRNA without increasing proteolysis in skeletal muscle Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2008; 294(6): R1777 - R1789. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. H. Lang, R. A. Frost, and T. C. Vary Skeletal muscle protein synthesis and degradation exhibit sexual dimorphism after chronic alcohol consumption but not acute intoxication Am J Physiol Endocrinol Metab, June 1, 2007; 292(6): E1497 - E1506. [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, E. Svanberg, and T. C. Vary IGF-I/IGFBP-3 ameliorates alterations in protein synthesis, eIF4E availability, and myostatin in alcohol-fed rats Am J Physiol Endocrinol Metab, June 1, 2004; 286(6): E916 - E926. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. A. Sneddon, M. Koll, M. C. Wallace, J. Jones, J. P. Miell, P. J. Garlick, and V. R. Preedy Acute alcohol administration inhibits the refeeding response after starvation in rat skeletal muscle Am J Physiol Endocrinol Metab, May 1, 2003; 284(5): E874 - E882. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. Kumar, R. A. Frost, and C. H. Lang Alcohol impairs insulin and IGF-I stimulation of S6K1 but not 4E-BP1 in skeletal muscle Am J Physiol Endocrinol Metab, November 1, 2002; 283(5): E917 - E928. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Tessari, D. Bruttomesso, A. Pianta, M. Vettore, M. Zanetti, E. Kiwanuka, and E. Iori Effects of wine intake on postprandial plasma amino acid and protein kinetics in type 1 diabetes Am. J. Clinical Nutrition, May 1, 2002; 75(5): 856 - 866. [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] |
||||
![]() |
C. H. Lang, R. A. Frost, V. Kumar, and T. C. Vary Impaired myocardial protein synthesis induced by acute alcohol intoxication is associated with changes in eIF4F Am J Physiol Endocrinol Metab, November 1, 2000; 279(5): E1029 - E1038. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. H. Lang, R. A. Frost, A. C. Nairn, D. A. MacLean, and T. C. Vary TNF-alpha impairs heart and skeletal muscle protein synthesis by altering translation initiation Am J Physiol Endocrinol Metab, February 1, 2002; 282(2): E336 - E347. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |