D-glucose induces a rise in pancreatic islet β-cell cytosolic [Ca2+] by processes requiring both glucose metabolism and Ca2+ entry from the extracellular space, and this Ca2+ signal is thought to be critical to the induction of insulin secretion. Insulin secretagogues also induce phospholipid hydrolysis and accumulation of phospholipid-derived mediators in islets, including the lipid messengers DAG, nonesterified arachidonic acid, and arachidonate 12-LO products. This study offers the following viewpoints on potential roles of these lipid messengers in insulin secretion as working hypotheses: 1) the Ca2+ signal provided to the β-cell by D-glucose induces insulin secretion only in the context of amplifying background signals provided by the β-cell content of messengers including DAG; 2) muscarinic receptor agonists amplify glucose-induced insulin secretion in part by altering the β-cell content of DAG; 3) the Ca2+ signal provided by metabolism of D-glucose is amplified by the level of nonesterified arachidonic acid in β-cell membranes, which acts to facilitate Ca2+ entry; 4) metabolism of glucose induces accumulation of nonesterified arachidonate in beta-cells via activation of a recently identified ASCI-PLA2 enzyme, which may be a component of the β-cell fuel sensor apparatus; and 5) arachidonate 12-LO metabolites are potential candidates as adjunctive modulators of β-cell K+-channel activity.
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Perspectives in Diabetes| March 01 1993
Amplification of Insulin Secretion by Lipid Messengers
Richard W Gross;
Address correspondence and reprint requests to Dr. John Turk, Box 8118, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110.
John Turk, Richard W Gross, Sasanka Ramanadham; Amplification of Insulin Secretion by Lipid Messengers. Diabetes 1 March 1993; 42 (3): 367–374. https://doi.org/10.2337/diab.42.3.367
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