Blackard W G, Li J, Clore J N, Rizzo W B
Department of Medicine, Medical College of Virginia/Virginia Commonwealth University, Richmond 23298, USA.
Lipids. 1997 Feb;32(2):193-8. doi: 10.1007/s11745-997-0024-1.
The fatty acid composition of the membrane phospholipids phosphatidylcholine (PC) and phosphatidylethanolamine in insulin-sensitive Type I (soleus) and insulin-resistant Type II (EDL) muscle is not known. In the present studies, soleus and EDL muscles were removed from 250-300 g Sprague-Dawley rats, and the fatty acid composition of total and individual phospholipid (PL) species was quantitated. As expected, triglyceride content was increased twofold in soleus muscle. No quantitative differences in the individual PL species or cholesterol content were found between the two muscles. However, a striking difference in PL fatty acid composition was observed in the PC fraction. An increase in 16:0 with decreases in 18:0, 18:1, 22:5n-3, and 22:6n-3 (P < 0.001 for each) was observed in the PC fraction of EDL compared to that from soleus, consistent with reduced elongation of PC fatty acids. Inhibition of fatty acid oxidation with the carnitine palmitoyl transferase-1 inhibitor, etomoxir, did not alter the fatty acid pattern in either muscle. We conclude that an alteration in PL fatty acid composition consistent with reduced elongation of both saturated and unsaturated fatty acids is observed in Type II muscle. The restriction of these alterations to the PC fraction has important implications.
胰岛素敏感的I型（比目鱼肌）和胰岛素抵抗的II型（趾长伸肌）肌肉中膜磷脂磷脂酰胆碱（PC）和磷脂酰乙醇胺的脂肪酸组成尚不清楚。在本研究中，从250 - 300克的Sprague-Dawley大鼠身上取下比目鱼肌和趾长伸肌，并对总磷脂（PL）和各磷脂种类的脂肪酸组成进行定量分析。正如预期的那样，比目鱼肌中的甘油三酯含量增加了两倍。在这两块肌肉之间，未发现各磷脂种类或胆固醇含量存在定量差异。然而，在PC组分中观察到磷脂脂肪酸组成存在显著差异。与比目鱼肌相比，趾长伸肌的PC组分中16:0增加，而18:0、18:1、22:5n-3和22:6n-3减少（每种均P < 0.001），这与PC脂肪酸的延长减少一致。用肉碱棕榈酰转移酶-1抑制剂依托莫昔抑制脂肪酸氧化，并未改变任何一块肌肉中的脂肪酸模式。我们得出结论，在II型肌肉中观察到磷脂脂肪酸组成发生改变，这与饱和脂肪酸和不饱和脂肪酸的延长减少一致。这些改变仅限于PC组分具有重要意义。
