Linked Life Data

6300099

Source:http://linkedlifedata.com/resource/pubmed/id/6300099

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1983-5-27
pubmed:abstractText
Incubation of intact rat adipocytes with physiological concentrations of insulin stimulates binding of insulin-like growth factor II (IGF-II) to its receptor by 3- to 10-fold. The effect is temperature- and dose-dependent, with 0.1 nM insulin giving half-maximal stimulation. Scatchard analysis of IGF-II binding to intact adipocytes indicates that this effect is due to an apparent increase in receptor affinity, from Kd = 63 nM in the absence of insulin to Kd = 5.8 nM in the presence of 10 nM insulin, with no apparent change in the number of cell surface binding sites (220,000/cell). Scatchard analysis of 125I-IGF-II binding to isolated membrane fractions demonstrated that all IGF-II receptors in plasma membranes and low density microsomes from control cells are converted during homogenization to the high affinity form (Kd = 2 to 6 nM) seen in insulin-treated intact adipocytes. No significant difference in affinity was observed between plasma membranes from control or insulin-treated adipocytes or between low density microsomes from control or insulin-treated cells. However, in apparent contrast to the results obtained in intact adipocytes, the number of binding sites is increased in the plasma membrane fraction from insulin-treated cells by an average of 60%, while the number of receptors is decreased by 40% in low density microsomes from insulin-treated cells compared to control cells. These results were confirmed by direct visualization of the Mr = 270,000 IGF-II receptor band on dodecyl sulfate gels following affinity labeling with 125I-IGF-II and the cross-linker disuccinimidyl suberate. Scatchard analysis of the total cellular membranes showed no difference in the total number of binding sites between control and insulin-treated cells. These results demonstrate that insulin has two effects on the IGF-II receptor in adipocytes. 1) It rapidly increases the apparent affinity of the receptor in the intact cell without changing the apparent number of receptors on the cell surface; and 2) it induces a redistribution of the high affinity IGF-II receptor between plasma membranes and low density microsomes upon homogenization of cells and preparation of membranes. The latter effect closely parallels the insulin-induced membrane redistribution of the glucose transporter that occurs in the rat adipocyte by an unknown mechanism.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4824-30
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Insulin action rapidly modulates the apparent affinity of the insulin-like growth factor II receptor.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't