Vanadate fully stimulates insulin receptor substrate‐1 associated phosphatidyl inositol 3‐kinase activity in adipocytes from young and old rats
- 27 March 1998
- journal article
- research article
- Published by Wiley in FEBS Letters
- Vol. 425 (2) , 298-304
- https://doi.org/10.1016/s0014-5793(98)00258-0
Abstract
Vanadate stimulates adipocyte 2-deoxyglucose transport and GLUT-4 translocation to the membrane through an insulin receptor-independent but wortmannin-inhibitable pathway. Vanadate stimulates PI 3-kinase in anti-IRS-1 immunoprecipitates and the binding between IRS-1 and the p85α subunit of PI 3-kinase. In insulin-resistant adipocytes from old rats vanadate fully stimulates IRS-1-associated PI 3-kinase, but partially activates glucose uptake. We conclude that: (a) vanadate stimulates 2-deoxyglucose uptake using a pathway that converges with that of insulin at the level of PI 3-kinase; and (b) adipocytes from old rats are defective in the insulin pathway at steps located both upstream and downstream of PI 3-kinase.Keywords
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