scholarly journals The effect of chronic ethanol ingestion on synthesis and degradation of soluble, contractile and stromal protein fractions of skeletal muscles from immature and mature rats

1989 ◽  
Vol 259 (1) ◽  
pp. 261-266 ◽  
Author(s):  
V R Preedy ◽  
T J Peters
Keyword(s):  
Protein Synthesis ◽  
Ethanol Exposure ◽  
Chronic Ethanol ◽  
Protein Fractions ◽  
Ethanol Ingestion ◽  
Ethanol Treatment ◽  
Male Wistar Rats ◽  
Ethanol Feeding ◽  
The Difference ◽  
Stromal Proteins

1. An investigation was carried out into the response of soluble, myofibrillar and stromal protein fractions of skeletal muscle to chronic ethanol feeding. Groups of male Wistar rats, of approx. 85 or 280 g body wt., were pair-fed on a nutritionally complete liquid diet containing glucose or a diet in which 36% of the total energy was provided by ethanol. After 6 weeks, rates of protein synthesis were measured with a flooding dose of L-[4-3H]phenylalanine. 2. The protein contents of soluble, myofibrillar and stromal fractions in gastrocnemius muscle from small and large rats were decreased by ethanol feeding. Greater changes were observed in small than in large rats. 3. Fractional synthesis rates of soluble, myofibrillar and stromal proteins of gastrocnemius were all decreased by ethanol treatment. All fractions responded similarly, though percentage decreases in large rats were greater than in small rats. Absolute synthesis rates in gastrocnemius muscles were also decreased after ethanol treatment. All protein fractions responded similarly, and the magnitudes of the responses in large and small rats were also similar. 4. Fractional rates of breakdown, measured by the difference between fractional growth and synthesis rates, were apparently decreased, in both sets of rats, in all protein fractions. 5. It was concluded that chronic ethanol exposure causes perturbations in soluble, myofibrillar and stromal protein accretion by a mechanism involving unidirectional changes in protein synthesis and possibly breakdown.

scholarly journals Inhibition of proteolysis in the liver by chronic ethanol feeding

1991 ◽  
Vol 273 (1) ◽  
pp. 149-152 ◽  
Author(s):  
A R Pösö ◽  
P Hirsimäki
Keyword(s):  
Drinking Water ◽  
Morphometric Analysis ◽  
Volume Density ◽  
Chronic Ethanol ◽  
Ethanol Treatment ◽  
Daily Consumption ◽  
Ethanol Feeding ◽  
The Difference ◽  
H Protein

Effects of chronic ethanol feeding on the volume density of lysosomes, the rate of protein degradation and the amount of protein were studied in livers perfused in situ at 07:00, 11:00, 17:00 and 23:00 h. Ethanol was given to the rats in drinking water for either 3 or 8-10 weeks. During week 3 of treatment and onwards, the average daily consumption of ethanol was 12.3 +/- 0.3 g/kg body wt. Morphometric analysis revealed that the volume density of autophagosomes and autolysosomes was lower in the ethanol-fed rats than in the controls. When compared with age-matched controls, the rate of proteolysis, measured as release of valine, was 33% and 26% less in the ethanol-fed rats after treatment for 3 and 8-10 weeks respectively. The difference between the two groups was most pronounced at 07:00 and 11:00 h. Protein content of the liver increased significantly after the longer ethanol treatment. According to these results, chronic ethanol feeding inhibits proteolysis in the liver by preventing the sequestration of protein into lysosomes.

scholarly journals The effect of chronic ethanol ingestion on protein metabolism in type-I- and type-II-fibre-rich skeletal muscles of the rat

1988 ◽  
Vol 254 (3) ◽  
pp. 631-639 ◽  
Author(s):  
V R Preedy ◽  
T J Peters
Keyword(s):  
Protein Synthesis ◽  
Protein Metabolism ◽  
Skeletal Muscle Fibre ◽  
Chronic Ethanol ◽  
Ethanol Ingestion ◽  
Type I ◽  
Type Ii ◽  
Ethanol Feeding ◽  
Dna 2 ◽  
Rna And Dna

1. The effects of chronic ethanol feeding on muscles containing a predominance of either Type I (aerobic, slow-twitch) or Type II (anaerobic, fast-twitch) fibres were studied. Male Wistar rats, weighing approx. 90 g or 280 g, were pair-fed on a nutritionally complete liquid diet containing 36% of total energy as ethanol, or isovolumetric amounts of the same diet in which ethanol was replaced by isoenergetic glucose. After 6 weeks feeding, fractional rates of protein synthesis were measured with a flooding dose of L-[4-(3)H]-phenylalanine and muscles were analysed for protein, RNA and DNA. 2. Ethanol feeding decreased muscle weight, protein, RNA and DNA contents in both small and large rats. Type-II-fibre-rich muscles showed greater changes than did Type-I-fibre-rich muscles. Changes in protein paralleled decreases in DNA. 3. The capacity for protein synthesis (RNA/protein), fractional rates of protein synthesis and absolute rates of protein synthesis were decreased by ethanol feeding in both small and large rats. The amounts of protein synthesized relative to RNA and DNA were also decreased. Changes were less marked in Type-I than in Type-II-fibre-rich muscles. Loss of protein, RNA and DNA was greater in small rats, but protein synthesis was more markedly affected in large rats. 4. It was concluded that chronic ethanol feeding adversely affects protein metabolism in skeletal muscle. Fibre composition and animal size are also important factors in determining the pattern of response.

Rat mitochondrial ATP synthase ATP5G3: cloning and upregulation in pancreas after chronic ethanol feeding

2001 ◽  
Vol 6 (2) ◽  
pp. 91-98 ◽  
Author(s):  
HA-SHENG LI ◽  
JI-YING ZHANG ◽  
BRYAN S. THOMPSON ◽  
XIAO-YING DENG ◽  
MICHAEL E. FORD ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Cellular Response ◽  
Molecular Mechanisms ◽  
Metabolic Stress ◽  
Nuclear Gene ◽  
Chronic Ethanol ◽  
Ethanol Ingestion ◽  
Pancreatic Acinar Cells ◽  
Mitochondrial Atp Synthase ◽  
Ethanol Feeding

Individuals with chronic excessive alcohol ingestion are put at the risk of acute and chronic pancreatitis. Underlying molecular mechanisms are unknown. Differential gene expression in the pancreas was profiled using mRNA differential display by comparison between control and ethanol-consuming rats. Male Wistar rats were fed with diets containing 6.7% (vol/vol) ethanol for 4 wk. A cDNA tag that was overexpressed in the pancreas of rats fed ethanol was isolated. A 723-bp cDNA was cloned from a rat pancreatic cDNA library, which encodes a novel rat mitochondrial ATP synthase subunit 9, isoform 3 (ATP5G3), which is homologous to a human ATP5G3 gene. Real-time PCR demonstrated that all three nuclear gene isoforms (ATP5G1, ATP5G2, and ATP5G3) were consistently upregulated in the pancreas of alcohol-consuming rats, parallel with mitochondrial injury. The cellular response to mitochondrial damage and metabolic stress may reflect an adaptive process for mitochondrial repair in pancreatic acinar cells during chronic ethanol ingestion.

Effect of chronic ethanol ingestion on pancreatic protein synthesis

1988 ◽  
Vol 966 (3) ◽  
pp. 390-402 ◽  
Author(s):  
Biddanda C. Ponnappa ◽  
Jan B. Hoek ◽  
Jan B. Hoek ◽  
Leslie Jubinski ◽  
Emanuel Rubin
Keyword(s):  
Protein Synthesis ◽  
Chronic Ethanol ◽  
Ethanol Ingestion

scholarly journals Decreased insulin-dependent glucose transport by chronic ethanol feeding is associated with dysregulation of the Cbl/TC10 pathway in rat adipocytes

2005 ◽  
Vol 289 (6) ◽  
pp. E1077-E1084 ◽  
Author(s):  
Becky M. Sebastian ◽  
Laura E. Nagy
Keyword(s):  
Glucose Transport ◽  
Actin Polymerization ◽  
Pi3k Pathway ◽  
Ethanol Exposure ◽  
Chronic Ethanol ◽  
Glucose Disposal ◽  
Filamentous Actin ◽  
Independent Manner ◽  
Increased Risk ◽  
Ethanol Feeding

Heavy alcohol consumption is an independent risk factor for type 2 diabetes. Although the exact mechanism by which alcohol contributes to the increased risk is unknown, impaired glucose disposal is a likely target. Insulin-stimulated glucose disposal in adipocytes is regulated by two separate and independent pathways, the PI3K pathway and the Cbl/TC10 pathway. Previous studies suggest that chronic ethanol feeding impairs insulin-stimulated glucose transport in adipocytes in a PI3K-independent manner. In search of potential targets of ethanol that would affect insulin-stimulated glucose transport, we investigated the effects of 4-wk ethanol feeding to male Wistar rats on the Cbl/TC10 pathway in isolated adipocytes. Chronic ethanol feeding inhibited insulin-stimulated cCbl phosphorylation compared with pair feeding. Insulin receptor and Akt/PKB phosphorylation were not affected by ethanol feeding. Chronic ethanol exposure also impaired cCbl and TC10 recruitment to a lipid raft fraction isolated from adipocytes by detergent extraction. Furthermore, chronic ethanol feeding increased the amount of activated TC10 and filamentous actin in adipocytes at baseline and abrogated the ability of insulin to further activate TC10 or polymerize actin. These results demonstrate that the impairment in insulin-stimulated glucose transport observed in adipocytes after chronic ethanol feeding to rats is associated with a disruption of insulin-mediated Cbl/TC10 signaling and actin polymerization.

Chronic ethanol feeding impairs endothelin-1-stimulated glucose uptake via decreased Gα11 expression in rat adipocytes

2003 ◽  
Vol 285 (2) ◽  
pp. E303-E310 ◽  
Author(s):  
Nadia Rachdaoui ◽  
Becky M. Sebastian ◽  
Laura E. Nagy
Keyword(s):  
Glucose Uptake ◽  
Plasma Membranes ◽  
Ethanol Exposure ◽  
Chronic Ethanol ◽  
Endothelin 1 ◽  
Rat Adipocytes ◽  
Downstream Target ◽  
Tyrosine Kinase 2 ◽  
Increase Glucose Uptake ◽  
Ethanol Feeding

Chronic ethanol feeding decreases insulin-stimulated glucose uptake in rat adipocytes. Here, we show that chronic ethanol also decreases endothelin-stimulated glucose uptake. Endothelin-1 increased uptake of 2-deoxyglucose 2.4-fold in adipocytes isolated from pair-fed rats. However, in adipocytes isolated from rats that had consumed a diet containing 35% ethanol for 4 wk, endothelin-1 did not increase glucose uptake. Although endothelin-1 increased GLUT4 quantity at the plasma membrane in adipocytes from pair-fed rats, there was no increase in GLUT4 after chronic ethanol feeding. Loss of endothelin-1-stimulated glucose uptake after ethanol feeding was associated with a specific decrease in the quantity of Gα11 in plasma membranes, with no change in Gαq quantity. Activation of proline-rich tyrosine kinase 2 (PYK2), a downstream target of Gαq/11 that is required for endothelin-1-stimulated GLUT4 translocation in 3T3-L1 adipocytes, was also suppressed after chronic ethanol feeding. In contrast, activation of p38 MAPK by endothelin-1 was not affected by chronic ethanol exposure. These data demonstrate that chronic ethanol feeding suppresses endothelin-1-stimulated glucose uptake and suggest that decreased expression of Gα11 coupled to impaired endothelin-1-dependent activation of PYK2 contributes to this response.

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