Tissue-specific regulation of IRS-2/PI 3-kinase association in aged rats.
We have examined the insulin-stimulated IRS-2 association with PI 3-kinase and the phosphorylation of AKT/PKB, which is functionally located downstream of the PI 3-kinase, in aged (obese) rats. The IRS-2 protein levels were similar in 2 and 20 month-old rats in both tissues, liver and muscle. There were reductions in insulin-induced IRS-2 tyrosine phosphorylation in liver and muscle, accompanied by a decrease in IRS-2/PI 3-kinase association and in AKT/PKB phosphorylation only in muscle tissue of aged rats. This regulation may be important in the altered glucose metabolism observed in aged (obese) rats.
Carvalho
C R
CR
Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, SP, Brazil.
Maeda
L
L
Brenelli
S L
SL
Saad
M J
MJ
D000375:Aging / Q000378:metabolism*; D000818:Animals; D007328:Insulin / Q000378:metabolism; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D051381:Rats; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism
D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; C526299:Irs2 protein, rat; D010750:Phosphoproteins; D014443:Tyrosine; D019869:Phosphatidylinositol 3-Kinases