PMID: 6989359Jan 15, 1980Paper

The stimulus-secretion coupling of glucose-induced insulin release. Metabolism of glucose in K+-deprived islets

The Biochemical Journal
A SenerW J Malaisse

Abstract

1. When pancreatic islets were exposed to a K(+)-free medium, the intracellular concentration of K(+) was decreased and that of Na(+) increased. 2. In the K(+)-deprived islets, the utilization of [5-(3)H]glucose, output of lactic acid and oxidation of [U-(14)C]-glucose were decreased by about 30-40% below the control values found at normal extracellular K(+) concentration (5.0mm). However, the oxidation of [U-(14)C]pyruvate was unaffected. 3. The omission of extracellular K(+) little affected the production of (14)CO(2) from islets prelabelled with [U-(14)C]palmitate and incubated in the absence of glucose, despite the fact that K(+) deprivation significantly increased the ATP concentration and ATP/ADP concentration ratio in the glucose-deprived islets. 4. At normal K(+) concentration, glucose increased the concentrations of phosphoenolpyruvate, NAD(P)H and ATP in the islets. In the glucose-stimulated islets, the concentration of phosphoenolpyruvate, but not that of either NAD(P)H or ATP, was higher in the absence than in the presence of extracellular K(+). In islet homogenates, the activity of pyruvate kinase (EC 2.7.1.40) was stimulated by K(+) (optimal activity at 100-150mm-K(+)) and inhibited by Na(+) (except at very low K(...Continue Reading

Citations

Dec 1, 1986·Acta Physiologica Scandinavica·P BergstenB Hellman
Oct 15, 1984·Experientia·A Sener, W J Malaisse
Jan 1, 1986·Diabetes/metabolism Reviews·M D Meglasson, F M Matschinsky
Jul 1, 1980·Naunyn-Schmiedeberg's Archives of Pharmacology·S KawazuW J Malaisse

Related Concepts

Adenine Nucleotides
Cations, Monovalent
Glucose, (beta-D)-Isomer
Glycolysis
Novolin
Islets of Langerhans
NADH
NADP
Oxidation-Reduction
Phosphoenolpyruvate

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