Linked Life Data

2472299

Source:http://linkedlifedata.com/resource/pubmed/id/2472299

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7
pubmed:dateCreated
1989-8-8
pubmed:abstractText
With a glucose-responsive beta-cell line (HIT cells), we tested the hypothesis that the cytosolic free-Ca2+ level ([Ca2+]i) is an intracellular signal through which a rise in cyclic AMP (cAMP) levels is transmitted to potentiate glucose-stimulated insulin secretion. In these cells, glucose stimulates the acute release of insulin without increasing [Ca2+]i or altering cAMP content. Either forskolin or 3-isobutylmethylxanthine (IBMX) potentiated glucose-stimulated insulin secretion and increased cAMP levels. At either a submaximal glucose concentration or maximally stimulatory glucose concentration, both IBMX and forskolin triggered a rapid rise in [Ca2+]i (1.9- and 1.5-fold increase over basal levels, respectively). Similarly, glucagon stimulated a 1.3-fold increase in [Ca2+]i over basal levels. The effect on [Ca2+]i required glucose and was secondary to Ca2+ influx through voltage-dependent Ca2+ channels because it was blocked by either chelation of extracellular Ca2+ with EGTA or by the Ca2+-channel blockers verapamil and nimodipine. Verapamil also inhibited IBMX potentiation of glucose-stimulated insulin secretion and the IBMX-induced rise in [Ca2+]i in a dose-dependent manner with IC50s of 2 x 10(-5) and 4 x 10(-6) M, respectively. We conclude that in the beta-cell, a rise in cAMP levels increases Ca2+ influx through voltage-dependent Ca2+ channels and that this represents a mechanism by which cAMP potentiates glucose-stimulated insulin secretion in beta-cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0012-1797
pubmed:author
pubmed:issnType
Print
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
874-80
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
Effect of rise in cAMP levels on Ca2+ influx through voltage-dependent Ca2+ channels in HIT cells. Second-messenger synarchy in beta-cells.
pubmed:affiliation
Department of Medicine, Baylor College of Medicine, Houston, TX 77030.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't