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Sexual dimorphic response for muscle protein synthesis and degradation after chronic alcohol consumption
Author(s) -
Lang Charles H.,
Frost Robert A.,
Vary Thomas C.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a331-a
Subject(s) - medicine , endocrinology , protein degradation , alcohol , ribosomal protein s6 , eif4e , proteolysis , biology , phosphorylation , biochemistry , p70 s6 kinase 1 , messenger rna , enzyme , translation (biology) , gene , protein kinase b
Human studies suggest alcoholic myopathy may be more severe in females than males. However, comparable studies in animals are lacking which makes elucidating the biochemical locus for this defect problematic. The present study determined whether muscle protein synthesis and degradation exhibit a sexual dymorphic response to either chronic alcohol consumption or acute alcohol intoxication. Male and female rats which consumed an alcohol‐containing diet or were pair‐fed for 26 wks (chronic), or received an intraperitoneal injection of alcohol (acute) to mimic binge drinking. In male rats, alcohol consumption decreased muscle protein synthesis 25%. This reduction was associated with a 2‐fold increase in the inactive eIF4E‐4EBP1 complex and a 60% reduction in the active eIF4E‐eIF4G complex. This redistribution of eIF4E was associated with decreased phosphorylation of both 4E‐BP1 and eIF4G (50–55%). The phosphorylation of ribosomal protein S6 was also reduced 60% in alcohol consuming male rats. Chronic alcohol consumption did not alter muscle protein synthesis or indicies of translation initiation in female rats. In contrast, chronic alcohol ingestion did not alter atrogin‐1 or MuRF‐1 mRNA content (biomarkers of proteolysis) in muscle of male rats, but increased expression of these regulators of proteolysis in females 50–100%. Acute alcohol intoxication produced a comparable decrease in muscle protein synthesis and translation initiation in both male and female rats. Our data show sexual dimophorism for muscle protein synthesis, translation initiation and proteolysis in response to chronic, but not acute, alcohol intoxication. (AA11290)