Acetylcholine stimulation of selective increases in stearic and arachidonic acids in phosphatidic acid in mouse pancreas.

During the acetylcholine-stimulated loss of phosphatidylinositol and gain in the level of phosphatidic acid in mouse pancreas, there is a selective increase in stearic and arachidonic acids in phosphatidic acid. The amounts parallel the decrease in phosphatidylinositol, which contains predominantly these two fatty acids. Addition of atropine to stimulated tissue reverses the changes. There is a selective disappearance of the stearoyl, arachidonoyl phosphatidic acid, and phosphatidylinositol increases. The changes support the hypothesis that the 1-stearoyl, 2-arachidonoyl diglyceride backbone of phosphatidylinositol becomes phosphatidic acid during acetylcholine stimulation, and is transformed back to phosphatidylinositol on reversion to the unstimulated state.