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Enzymes of phospholipid metabolism in rat pancreatic islets: Subcellular distribution and the effect of glucose and calcium
Author(s) -
Rana Rajendra S.,
Kowluru Anjaneyulu,
MacDonald Michael J.
Publication year - 1986
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240320206
Subject(s) - lysophosphatidylcholine , acyltransferase , pancreatic islets , inositol , biochemistry , chemistry , diglyceride , phospholipid , islet , enzyme , biology , medicine , endocrinology , insulin , phosphatidylcholine , membrane , receptor
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 activites. 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 lyso‐phosphatidylcholine 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.