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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
5
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pubmed:dateCreated |
1979-9-25
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pubmed:abstractText |
When isolated rat islets were exposed to glucose, the concentrations of NADH and NADPH, and the NADH/NAD+ and NADPH/NADP+ ratios were increased. The dose-response curve resembled that characterising the glucose-induced secondary rise in 45Ca efflux, displaying a sigmoidal pattern with a half-maximal value at glucose 7.5 mmol/l. The glucose-induced increase in NAD(P)H was detectable within 1 min of exposure to the sugar. Except for the fall in ATP concentration and ATP/ADP ratio found at very low glucose concentrations (zero to 1.7 mmol/l) no effect of glucose (2.8-27.8 mmol/l) upon the steady-state concentration of adenine nucleotides was observed. However, a stepwise increase in glucose concentration provoked a dramatic and transient fall in the ATP concentration, followed by a sustained increase in both O2 consumption and oxidation of exogenous + endogenous nutrients. This may be essential to meet the energy requirements in the stimulated B-cell. Although no significant effect of glucose upon intracellular pH was detected by the 5,5-dimethyloxazolidine-2,4-dione method, the net release of H+ was markedly increased by glucose, with a hyperbolic dose-response curve (half-maximal response at glucose 2.9 mmol/l) similar to that characterising the glucose-induced initial fall in 45Ca efflux. It is proposed that the generation of both NAD(P)H and H+ participates in the coupling of glucose metabolism to distal events in the secretory sequence, especially the ionophoretic process of Ca2+ inward and outward transport, and that changes in these parameters occur in concert with an increased turn-over rate of high-energy phosphate intermediates.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Adenine Nucleotides,
http://linkedlifedata.com/resource/pubmed/chemical/Antimycin A,
http://linkedlifedata.com/resource/pubmed/chemical/Glucose,
http://linkedlifedata.com/resource/pubmed/chemical/Insulin,
http://linkedlifedata.com/resource/pubmed/chemical/Mannoheptulose,
http://linkedlifedata.com/resource/pubmed/chemical/NAD,
http://linkedlifedata.com/resource/pubmed/chemical/NADP
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pubmed:status |
MEDLINE
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pubmed:month |
May
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pubmed:issn |
0012-186X
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
16
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
331-41
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pubmed:dateRevised |
2011-11-17
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pubmed:meshHeading |
pubmed-meshheading:37138-Adenine Nucleotides,
pubmed-meshheading:37138-Animals,
pubmed-meshheading:37138-Antimycin A,
pubmed-meshheading:37138-Female,
pubmed-meshheading:37138-Glucose,
pubmed-meshheading:37138-Insulin,
pubmed-meshheading:37138-Islets of Langerhans,
pubmed-meshheading:37138-Mannoheptulose,
pubmed-meshheading:37138-NAD,
pubmed-meshheading:37138-NADP,
pubmed-meshheading:37138-Oxygen Consumption,
pubmed-meshheading:37138-Rats
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pubmed:year |
1979
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pubmed:articleTitle |
The stimulus-secretion coupling of glucose-induced insulin release. XXXV. The links between metabolic and cationic events.
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pubmed:publicationType |
Journal Article
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