Linked Life Data

9030192

Source:http://linkedlifedata.com/resource/pubmed/id/9030192

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1997-3-13
pubmed:abstractText
We have previously reported that pancreatic islet beta-cells and clonal HIT insulinoma cells express an ATP-stimulatable Ca(2+)-independent phospholipase A2 (ASCI-PLA2) enzyme and that activation of this enzyme appears to participate in glucose-stimulated insulin secretion. To further examine this hypothesis, glucose-responsitivity and expression of ASCI-PLA2 activity in various insulinoma cell lines were examined. Secretagogue-stimulated insulin secretion was observed with beta TC6-f7 and early passage (EP)-beta TC6 cells. In contrast, RIN-m5f, beta TC3, and late passage (LP)-beta TC6 cells exhibited little secretagogue-induced secretion. A haloenollactone suicide substrate (HELSS) which inhibits ASCI-PLA2 activity ablated secretagogue-induced insulin secretion from beta TC6-f7 and EP-beta TC6 cells. All insulinoma cell lines studied expressed both cytosolic and membrane-associated Ca(2+)-independent PLA2 activities which were inhibited by HELSS. The cytosolic enzymatic activity in the glucose-responsive beta TC6-f7 and EP-beta TC6 cells was activated by ATP and protected against thermal denaturation by ATP, but this was not the case in the glucose-unresponsive RIN-m5f, beta TC3, or LP-beta TC6 cells. Comparison of the distribution of Ca(2+)-independent PLA2 activity revealed that membrane-associated activity was higher than cytosolic activity in beta TC6-f7 and EP-beta TC6 cells but not in RIN-m5f, beta TC3, or LP-beta TC6 cells. Insensitivity of cytosolic activity to ATP may prevent association of the PLA2 activity with membrane substrates and contribute to attenuated glucose-responsitivity in the RIN-m5f, beta TC3, or LP-beta TC6 cells. HIT insulinoma cells were also found to undergo a decline in both glucose-responsitivity and membrane-associated Ca(2+)-independent PLA2 activity upon serial passage in culture, and this was associated with a reduction in membrane content of arachidonate-containing phospholipids. These and previous results suggest that the ATP-stimulatable PLA2 enzyme may participate in glucose-induced insulin secretion.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
1344
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
153-64
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Glucose-responsitivity and expression of an ATP-stimulatable, Ca(2+)-independent phospholipase A2 enzyme in clonal insulinoma cell lines.
pubmed:affiliation
Washington University School of Medicine, St. Louis, MO 63110, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't