Effect of Unsaturated Fatty Acids and Ca2+ on Phosphatidylinositol Synthesis and Breakdown
1982 年 91 巻 3 号 p. 793-799
詳細
1982 年 91 巻 3 号 p. 793-799
CDP-diglyceride: inositol transferase was inhibited by unsaturated fatty acids. The inhibitory activity decreased in the following order: arachidonic acid>linolenic acid>linoleie acid>oleic acid_??_palmitoleic acid. Saturated fatty acids such as myristic acid, palmitic acid, and stearic acid had no effect. Calcium ion also inhibited the activity of CDP-diglyceride: inositol transferase.
In rat hepatocytes, arachidonic acid inhibited 32P incorporation into phosphatidylinositol and phosphatidic acid without any significant effect on 32P incorporation into phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine. Ca2+ ionophore A 23187 also inhibited 32P incorporation into phosphatidylinositol. However, 32P incorporation into phosphatidic acid was stimulated with Ca2+ ionophore A 23187.
Phosphatidylinositol-specific phospholipase C was activated by unsaturated fatty acids. Polyunsaturated fatty acids such as arachidonic acid and linolenic acid had a stronger effect than di- and monounsaturated fatty acids. Saturated fatty acids had no effect on the phospholipase C activity. The phospholipase C required Ca 2- for activity. Arachidonic acid and Ca2+ had synergistic effects.
These results suggest the reciprocal regulation of phosphatidylinositol synthesis and breakdown by unsaturated fatty acids and Ca2+.
