Linked Life Data

2203766

Source:http://linkedlifedata.com/resource/pubmed/id/2203766

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
25
pubmed:dateCreated
1990-10-9
pubmed:abstractText
The hamster islet B cell line HIT retains the ability to secret insulin in response to glucose and several receptor agonists. We used HIT cells to study the initial signaling events in glucose or receptor agonist-stimulated insulin secretion. Glucose stimulated insulin release from HIT cells in a dose-dependent manner with a half-maximal effect seen already at 1 mM. Insulin release was also stimulated by carbachol in a glucose-dependent manner. Glucose depolarized the HIT cell membrane potential as assessed with the fluorescent probe bisoxonol and raised intracellular Ca2+ as revealed by fura-2 measurements. Using a Mn2+ fura-2 quenching technique, we could show that the rise in intracellular Ca2+ was due to Ca2+ influx following opening of voltage-gated Ca2+ channels. Glucose is thought to increase the diacylglycerol (DAG) content of insulin-secreting cells. However, although HIT cells respond to glucose in terms of insulin secretion, membrane depolarization, and Ca2+ rise, the hexose was unable to increase the proportion of protein kinase C activity associated with membranes. In contrast, the membrane-associated protein kinase C activity increased in HIT cells exposed to the two receptor agonists carbachol and bombesin. Bombesin was shown to generate DAG with the expected fatty acid composition of activators of phospholipase C. Glucose, in contrast, only caused minor increases in DAG containing myristic and palmitic acid without affecting total DAG mass. The failure to detect stimulation of protein kinase C by glucose could be due to both the limited amount and to the different fatty acid composition of the metabolically generated DAG. The latter was in part supported by experiments performed on protein kinase C partially purified from HIT cells. Indeed, 1,2-dipalmitoylglycerol, presumed to be the main DAG species generated by glucose, was only one-third as active as 1,2-dioleoylglycerol and 1-stearoyl-2-arachidonylglycerol in stimulating the isolated enzyme at physiological Ca2+ concentration. It is therefore unlikely that DAG and protein kinase C play a major role in glucose-stimulated insulin secretion.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
265
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15003-9
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Stimulus-response coupling in insulin-secreting HIT cells. Effects of secretagogues on cytosolic Ca2+, diacylglycerol, and protein kinase C activity.
pubmed:affiliation
Department of Medicine, University of Geneva, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't