Fluorometry and high-performance liquid chromatography were used to measure the content of free CoA and the esters of acetate, malonate, succinate, and long-chain fatty acids in isolated perifused rat pancreatic islets exposed to 25 mM glucose or a mixture of fuels (25 mM glucose plus 10 mM glutamine, 10 mM lactate, and 1 mM pyruvate) to assess the role of intermediates of lipid metabolism as candidate metabolic coupling factors in the mechanism of fuel-induced insulin secretion. Insulin secretion was stimulated in a biphasic manner with the fuel mixture, showing twice the potency compared with high glucose alone. Islets perifused for 3 min with high glucose alone or the fuel mixture compared with 2.5 mM glucose showed a significant increase in malonyl-CoA and succinyl-CoA and a decrease in acetyl-CoA. Free CoA and long-chain acyl-CoA levels were unaltered. Perifused islets stimulated with 25 mM glucose for 30 min showed a significant increase in succinyl-CoA and long-chain acyl-CoA and decrease in acetyl-CoA, whereas malonyl-CoA was not affected. However, when islets were stimulated by the fuel mixture for 30 min, malonyl-CoA was maintained at a high level, and the change in succinyl-CoA and long-chain acyl-CoA was similar to that observed in islets stimulated with 25 mM glucose alone. The acetyl-CoA concentration in the islets stimulated with the fuel mixture decreased slightly. These results confirm the viability of the hypothesis that malonyl-CoA and long-chain acyl-CoA serve as metabolic coupling factors in signal transduction when islets are stimulated by high glucose or glucose combined with other fuels.
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Original Articles| March 01 1991
Content of CoA-Esters in Perifused Rat Islets Stimulated by Glucose and Other Fuels
Address correspondence and reprint requests to Dr. F.M. Matschinsky, Diabetes Research Center, 501 Medical Education Building, University of Pennsylvania School of Medicine, Philadelphia, PA 19104–6015.
Yin Liang, Franz M Matschinsky; Content of CoA-Esters in Perifused Rat Islets Stimulated by Glucose and Other Fuels. Diabetes 1 March 1991; 40 (3): 327–333. https://doi.org/10.2337/diab.40.3.327
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