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Elevated Plasma Fatty Acids Suppress Intramyocellular Triglyceride Turnover and Synthesis Simultaneously in High fat‐fed Obese Rats
Author(s) -
Guo ZengKui,
Zhou Lianzhen,
Jensen Michael D
Publication year - 2006
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.20.5.a1038-c
Subject(s) - medicine , endocrinology , glycerol , chemistry , triglyceride , skeletal muscle , soleus muscle , metabolism , fatty acid , biochemistry , biology , cholesterol
This study was designed to test whether elevated plasma fatty acids contribute to excess accumulation of intramyocellular triglycerides (imcTG) in skeletal muscle of obesity by acutely raising postabsorptive plasma fatty acids (FA) by 15% (L) and 30% (H) to determine imcTG synthesis and fractional turnover rate (FTR) using pulse ( 14 C‐glycerol)‐chase ( 3 H‐glycerol) technique in high fat‐fed obese rats. Plasma free glycerol and insulin were not affected by FA infusion (P>0.05). The rates of glycerol incorporation into imcTG (nmol/g/min) at 0, L and H of FA infusion were, respectively: soleus 4.5±0.6, 3.7±0.6 (P=0.4) and 2.2±0.2 (P<0.01), gastrocnemius 5.0±1, 2.2±0.5 (P=0.02) and 2.3±0.5 (P=0.03) and tibialis anterior 9.6±1.6, 3.8±1 (P=0.01) and 3.0±0.9 (P=0.01). imcTG FTR was also suppressed in gastrocnemius [3.7±0.5 to 2.4±0.5 (L, P<0.01) and 2.2±0.3%/min (H, P<0.01)] and tibialis anterior [4.1±0.7 to 2.1±0.4 (L, P<0.01) and 2.1±0.4%/min (H, P<0.01)], but not affected in soleus (1.1±0.4 to 1.1±0.4 and 0.9±0.1%/min for L and H, respectively, P>0.05). imcTG pool size (μmol/g) was not affected (P>0.9): soleus 10.7±1, 10.4±0.8 and 10.3±1, gastrocnemius 2.5±0.2, 2.4±0.1 and 2.5±0.2 and tibialis anterior 2.9±0.2, 2.8±0.3 and 2.8±0.3 for 0, L and H, respectively, nor was hormone sensitive lipase activity (P>0.05). It is concluded that exogenous fatty acids modulate imcTG synthesis and turnover similarly and thus do not appear to contribute to imcTG accumulation at least in this obesity model.