Interactions between the metabolism of L-leucine and D-glucose in the pancreatic beta-cells.
Beta-Cell-rich pancreatic islets microdissected from obese-hyperglycemic mice were used to study interactions between the metabolism of L-leucine and D-glucose. L-leucine reduced the islet content of aspartic acid whereas D-glucose, when added to L-leucine-incubated islets, increased the contents of aspartic acid and gamma-aminobutyric acid (GABA). D-glucose also increased the incorporation of L-leucine carbon into aspartic acid, GABA and glutamic acid suggesting stimulation of a malate shuttle mechanism. When expressed per mole of the individual amino acids, the incorporation of L-leucine carbon into GABA was 2.5-4 times higher than into glutamic acid indicating intracellular compartmentation of the latter amino acid. Both L-leucine and D-leucine stimulated 14CO2 production from 14C-labelled D-glucose. L-leucine did not affect 3H2O production from tritiated D-glucose. The present data do not indicate a role of other amino acids or D-glucose in L-leucine-stimulated insulin release.
D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D005971:Glutamates / Q000378:metabolism; D006019:Glycolysis / Q000187:drug effects; D006943:Hyperglycemia / Q000378:metabolism; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D007930:Leucine / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D008820:Mice, Obese; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D005971:Glutamates; D001224:Aspartic Acid; D005680:gamma-Aminobutyric Acid; D007930:Leucine; D005947:Glucose