Linked Life Data

8599611

Source:http://linkedlifedata.com/resource/pubmed/id/8599611

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1996-4-30
pubmed:abstractText
Glucagon enhances the electrical activity of pancreatic beta-cells. The mechanism of the glucagon-evoked enhancement of electrical activity was investigated in terms of glucose metabolism. ICR mice aged 6-12 weeks were used for experiments. Intracellular Ca2+ increased in parallel with the enhancement of electrical activity. The stimulating effect of glucagon on Ca2+ oscillation was suppressed by calmodulin-antagonists (Chlorpromazine, W-7, and trifluoperazine). To trace the glucagon-evoked change in glucose metabolism, the reduced pyridine nucleotide (NAD(P)H) fluorescence was monitored using the microfluorometry with the excitation of 360 nm and the emission of 465 nm in islet cell clusters mainly consisting of beta-cells. In the presence of 2.5 mM Ca2+ glucagon (8.6 X 10(-8) M) increased the NAD(P)H fluorescence, while in the absence of Ca2+ the hormone had no effect on the fluorescence. Extracellular Ca2+ removal from the glucagon-containing perifusion solution decreased the fluorescence to the level which had been attained before glucagon was added. Chlorpromazine (10 microM) reversed the glucagon-induced increase of NAD(P)H fluorescence as well as removing Ca2+ W-7 (15 microM) and trifluoperazine (30 microM) also suppressed the glucagon-induced increase of NAD(P)H. These results suggest that Ca2+/calmodulin system is involved in the acceleration of glycogenolysis by glucagon in beta-cells. On the basis of these observations, the mechanism of glucagon-induced enhancement of electrical activity and the relative ineffectiveness of glucagon at low glucose concentrations were discussed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
29
pubmed:volume
1310
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
325-33
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Glucagon induces Ca2+-dependent increase of reduced pyridine nucleotides in mouse pancreatic beta-cells.
pubmed:affiliation
Department of Physiology, Shiga University of Medical Science, Ohtsu, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't