Loizou C L, Ozanne S E, Hales C N
Department of Clinical Biochemistry, University of Cambridge, Addenbrooke's Hospital, UK.
Prostaglandins Leukot Essent Fatty Acids. 1999 Aug;61(2):89-95. doi: 10.1054/plef.1999.0076.
In humans there is a correlation between the ratio of arachidonic acid (20:4n-6) to cis 8,11,14 eicosatrienoic acid (20:3n-6) in skeletal muscle phospholipids and insulin sensitivity. This has been interpreted as indicating a link between the activity of the delta5 desaturase enzyme and muscle insulin sensitivity. The present study addressed the possibility that insulin regulates delta5 desaturase activity using L6 rat myoblasts and hepG2 human hepatoma cells. Both cell lines responded to insulin by increasing the amount of D-[U-14C] glucose incorporated into glycogen. In L6 cells, insulin stimulated cis 8,11,14 eicosatrienoic acid uptake and arachidonic acid production but had no effect on the percentage conversion of cis 8,11,14 eicosatrienoic acid to arachidonic acid. In hepG2 cells, insulin had no effect on cis 8,11,14 eicosatrienoic acid uptake or arachidonic acid production. These results suggest that insulin has no direct effect on delta5 desaturase activity in the liver but can alter arachidonic acid production in muscle by altering substrate availability.
在人类中，骨骼肌磷脂中花生四烯酸（20:4n-6）与顺式8,11,14-二十碳三烯酸（20:3n-6）的比例与胰岛素敏感性之间存在相关性。这被解释为表明δ5去饱和酶的活性与肌肉胰岛素敏感性之间存在联系。本研究探讨了胰岛素利用L6大鼠成肌细胞和HepG2人肝癌细胞调节δ5去饱和酶活性的可能性。两种细胞系都通过增加掺入糖原中的D-[U-14C]葡萄糖量来响应胰岛素。在L6细胞中，胰岛素刺激顺式8,11,14-二十碳三烯酸摄取和花生四烯酸生成，但对顺式8,11,14-二十碳三烯酸向花生四烯酸的转化率没有影响。在HepG2细胞中，胰岛素对顺式8,11,14-二十碳三烯酸摄取或花生四烯酸生成没有影响。这些结果表明，胰岛素对肝脏中的δ5去饱和酶活性没有直接影响，但可以通过改变底物可用性来改变肌肉中花生四烯酸的生成。
