Accelerated intramyocellular triglyceride synthesis in skeletal muscle of high-fat-induced obese rats

Research output: Contribution to journalArticle

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Abstract

OBJECTIVE: To test the hypothesis that the synthesis of intramyocellular triglycerides (imcTG) in skeletal muscle is increased in obese rats in which the content of imcTG is known to be abnormally high. ANIMALS: Sprague-Dawley male lean and high-fat-induced obese rats were studied at the age of 4, 8 and 12 months after an overnight fast, awake. MEASUREMENTS: [U- 14C]glycerol was continuously infused intravenously for 2 h followed by muscle biopsies, and intracellular glycerol incorporation into imcTG was determined. imcTG content, intramyocellular free glycerol concentration and specific activity, systemic glycerol flux and plasma glycerol, free fatty acid (FFA) and glucose concentrations were also determined. RESULTS: The rates of incorporation of intramyocellular glycerol into imcTG (nmol/g wet muscle/h) were markedly accelerated in obese rats compared to their lean littermates at all ages: 66±12 vs 12±2 (P=0.02) for gastrocnemius and 74±29 vs 31±7 (P=0.09) for soleus when 4 months old; 223±29 vs 58±27 (P=0.001) for gastrocnemius, 224±28 vs 70±21 (P=0.001) for soleus and 294±78 vs 49±22 (P=0.02) for tibialis anterior when 8 months old; and 25±4 vs 11±2 (P=0.01) for gastrocnemius and 22±8 vs 8.4±3 (P=0.04) for soleus when 12 months old. As expected, this was accompanied by a higher imcTG content in virtually all muscles at all ages tested. CONCLUSION: The synthesis of imcTG in skeletal muscle is grossly increased in obese rats, which likely contributes to abnormal imcTG accumulation.

Original languageEnglish (US)
Pages (from-to)1014-1019
Number of pages6
JournalInternational Journal of Obesity
Volume27
Issue number9
DOIs
StatePublished - Sep 1 2003

Fingerprint

skeletal muscle
Skeletal Muscle
Triglycerides
Fats
triacylglycerols
Glycerol
glycerol
synthesis
rats
lipids
Muscles
muscles
Nonesterified Fatty Acids
free fatty acids
biopsy
Biopsy
Glucose
glucose
testing

Keywords

  • Glycerol kinetics
  • Insulin resistance
  • Muscle lipid
  • TG-glycerol cycle

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Public Health, Environmental and Occupational Health
  • Endocrinology
  • Food Science
  • Endocrinology, Diabetes and Metabolism

Cite this

Accelerated intramyocellular triglyceride synthesis in skeletal muscle of high-fat-induced obese rats. / Guo, Z. K.; Jensen, Michael Dennis.

In: International Journal of Obesity, Vol. 27, No. 9, 01.09.2003, p. 1014-1019.

Research output: Contribution to journalArticle

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abstract = "OBJECTIVE: To test the hypothesis that the synthesis of intramyocellular triglycerides (imcTG) in skeletal muscle is increased in obese rats in which the content of imcTG is known to be abnormally high. ANIMALS: Sprague-Dawley male lean and high-fat-induced obese rats were studied at the age of 4, 8 and 12 months after an overnight fast, awake. MEASUREMENTS: [U- 14C]glycerol was continuously infused intravenously for 2 h followed by muscle biopsies, and intracellular glycerol incorporation into imcTG was determined. imcTG content, intramyocellular free glycerol concentration and specific activity, systemic glycerol flux and plasma glycerol, free fatty acid (FFA) and glucose concentrations were also determined. RESULTS: The rates of incorporation of intramyocellular glycerol into imcTG (nmol/g wet muscle/h) were markedly accelerated in obese rats compared to their lean littermates at all ages: 66±12 vs 12±2 (P=0.02) for gastrocnemius and 74±29 vs 31±7 (P=0.09) for soleus when 4 months old; 223±29 vs 58±27 (P=0.001) for gastrocnemius, 224±28 vs 70±21 (P=0.001) for soleus and 294±78 vs 49±22 (P=0.02) for tibialis anterior when 8 months old; and 25±4 vs 11±2 (P=0.01) for gastrocnemius and 22±8 vs 8.4±3 (P=0.04) for soleus when 12 months old. As expected, this was accompanied by a higher imcTG content in virtually all muscles at all ages tested. CONCLUSION: The synthesis of imcTG in skeletal muscle is grossly increased in obese rats, which likely contributes to abnormal imcTG accumulation.",
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N2 - OBJECTIVE: To test the hypothesis that the synthesis of intramyocellular triglycerides (imcTG) in skeletal muscle is increased in obese rats in which the content of imcTG is known to be abnormally high. ANIMALS: Sprague-Dawley male lean and high-fat-induced obese rats were studied at the age of 4, 8 and 12 months after an overnight fast, awake. MEASUREMENTS: [U- 14C]glycerol was continuously infused intravenously for 2 h followed by muscle biopsies, and intracellular glycerol incorporation into imcTG was determined. imcTG content, intramyocellular free glycerol concentration and specific activity, systemic glycerol flux and plasma glycerol, free fatty acid (FFA) and glucose concentrations were also determined. RESULTS: The rates of incorporation of intramyocellular glycerol into imcTG (nmol/g wet muscle/h) were markedly accelerated in obese rats compared to their lean littermates at all ages: 66±12 vs 12±2 (P=0.02) for gastrocnemius and 74±29 vs 31±7 (P=0.09) for soleus when 4 months old; 223±29 vs 58±27 (P=0.001) for gastrocnemius, 224±28 vs 70±21 (P=0.001) for soleus and 294±78 vs 49±22 (P=0.02) for tibialis anterior when 8 months old; and 25±4 vs 11±2 (P=0.01) for gastrocnemius and 22±8 vs 8.4±3 (P=0.04) for soleus when 12 months old. As expected, this was accompanied by a higher imcTG content in virtually all muscles at all ages tested. CONCLUSION: The synthesis of imcTG in skeletal muscle is grossly increased in obese rats, which likely contributes to abnormal imcTG accumulation.

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