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- Title
The stimulus-secretion coupling of amino acid-induced insulin release. Secretory and oxidative response of pancreatic islets to L-asparagine.
- Authors
Malaisse-Lagae, Francine; Welsh, Michael; Lebrun, Philippe; Herchuelz, Andre; Sener, Abdullah; Hellerström, Claes; Malaisse, Willy J.; Malaisse-Lagae, F; Welsh, M; Lebrun, P; Herchuelz, A; Sener, A; Hellerström, C; Malaisse, W J
- Abstract
L-Asparagine (2-10 mM) failed to affect insulin secretion from rat pancreatic islets incubated in the absence of exogenous nutrient or presence of D-glucose, but caused a dose-related and progressive enhancement of insulin release evoked by L-leucine, 2-aminobicyclo[2,2,1]heptane-2-carboxylate, or 2-ketoisocaproate. The secretory response to the combination of L-asparagine and L-leucine was augmented by theophylline and inhibited in the absence of extracellular Ca2+ or presence of either menadione or methylamine. L-Asparagine augmented leucine-stimulated 45Ca net uptake. The ATP content, rate of O2 uptake, and malate/pyruvate ratio were not significantly different in islets exposed to L-leucine alone or to both L-asparagine and L-leucine, respectively. In the sole presence of L-asparagine, however, the malate/oxalacetate ratio was decreased and the malate/pyruvate ratio increased, relative to basal values. It is proposed that the enhancing action of L-asparagine upon insulin release evoked by L-leucine might be due to an accelerated generation rate of cytosolic NADPH, rather than to any sizable increase in either islet respiration or steady-state cytosolic NADPH/NADP+ ratio.
- Publication
Diabetes, 1984, Vol 33, Issue 5, p464
- ISSN
0012-1797
- Publication type
journal article
- DOI
10.2337/diab.33.5.464