Linked Life Data

3005261

Source:http://linkedlifedata.com/resource/pubmed/id/3005261

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1986-3-28
pubmed:abstractText
Stimulation of the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) by a phospholipase C to produce inositol trisphosphate (InsP3) and 1,2-diacylglycerol appears to be the initial step in signal transduction for a number of cell-surface interacting stimuli, including thyrotropin-releasing hormone (TRH). In suspensions of membranes isolated from rat pituitary (GH3) cells that were prelabeled to isotopic steady state with [3H]inositol and incubated with ATP, [3H] PtdIns(4,5)P2, and [3H]phosphatidylinositol 4-phosphate, the polyphosphoinositides, and [3H]InsP3 and [3H]inositol bisphosphate, the inositol polyphosphates, accumulated. TRH and GTP stimulated the accumulation of [3H]inositol polyphosphates in time- and concentration-dependent manners; half-maximal effects occurred with 10-30 nM TRH and with 3 microM GTP. A nonhydrolyzable analog of GTP also stimulated [3H] inositol polyphosphate accumulation. Moreover, when TRH and GTP were added together their effects were more than additive. Fixing the free Ca2+ concentration in the incubation buffer at 20 nM, a value below that present in the cytoplasm in vivo did not inhibit stimulation by TRH and GTP of [3H]inositol polyphosphate accumulation. ATP was necessary for basal and stimulated accumulation of [3H]inositol polyphosphates, and a nonhydrolyzable analog of ATP could not substitute for ATP. These data demonstrate that TRH and GTP act synergistically to stimulate the accumulation of InsP3 in suspensions of pituitary membranes and that ATP, most likely acting as substrate for polyphosphoinositide synthesis, was necessary for this effect. These findings suggest that a guanine nucleotide-binding regulatory protein is involved in coupling the TRH receptor to a phospholipase C that hydrolyzes PtdIns(4,5)P2.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
261
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2712-7
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Thyrotropin-releasing hormone and GTP activate inositol trisphosphate formation in membranes isolated from rat pituitary cells.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.