Enzymes of phospholipid metabolism in rat pancreatic islets: Subcellular distribution and the effect of glucose and calcium

✍ Scribed by Rajendra S. Rana; Anjaneyulu Kowluru; Michael J. MacDonald

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 463 KB
• Volume: 32
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240320206

✦ Synopsis

The effect of glucose and calcium on the activities of the phosphatidylinositol cycle enzymes, CDP-diglyceride inositol transferase, diacylglycerokinase, and lysophosphatidylcholine 2-acyltransferase in rat pancreatic islets was studied. Calcium inhibited the activity of CDP-diglyceride inositol transferase but had no effect on lysophosphatidylcholine 2-acyltransferase and diacylglycerokinase activities. Upon preincubation of islets in a concentration of glucose known to stimulate insulin release, the activity of lysophosphatidylcholine 2-acyltransferase, but not that of diacylglycerokinase or the CDP-diglyceride inositol transferase, was stimulated. Subcellular fractionation of pancreatic islets showed that secretory granule membranes were enriched in CDP-diglyceride inositol transferase, whereas lysophosphatidylcholine 2-acyltransferase activity was highest in the microsomal membranes. The activation of 2-acyltransferase by incubating islets in insulinotropic glucose, and the calcium sensitivity of CDP-diglyceride inositol transferase, suggest that these enzymes may have roles in regulation of insulin secretion.