scholarly journals Effects of free fatty acids on glucose transport and IRS-1–associated phosphatidylinositol 3-kinase activity

1999 ◽  
Vol 103 (2) ◽  
pp. 253-259 ◽  
Author(s):  
Alan Dresner ◽  
Didier Laurent ◽  
Melissa Marcucci ◽  
Margaret E. Griffin ◽  
Sylvie Dufour ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
Glucose Transport ◽  
Kinase Activity ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

scholarly journals Lysophosphatidic acid stimulates glucose transport in Xenopus oocytes via a phosphatidylinositol 3′-kinase with distinct properties

1996 ◽  
Vol 316 (1) ◽  
pp. 161-166 ◽  
Author(s):  
Fiona J. THOMSON ◽  
Colin MOYES ◽  
Pamela H. SCOTT ◽  
Robin PLEVIN ◽  
Gwyn W. GOULD
Keyword(s):  
Phosphatidic Acid ◽  
Glucose Transport ◽  
Lysophosphatidic Acid ◽  
Xenopus Oocytes ◽  
Kinase Activity ◽  
Sugar Transport ◽  
Phosphatidylinositol 3 Kinase ◽  
Marked Contrast ◽  
Igf I ◽  
Phosphatidylinositol 3

Lysophosphatidic acid (LPA) stimulated the transport of deoxyglucose into oocytes isolated from Xenopus laevis. This stimulation was accounted for entirely by an increase in the Vmax for transport. Various LPAs with different acyl groups in the sn-1 position and phosphatidic acid stimulated deoxyglucose (deGlc) transport in these cells with a rank order potency of 1-oleoyl-LPA > 1-palmitoyl-LPA > phosphatidic acid = 1-stearoyl-LPA > 1-myristoyl-LPA. The phosphatidylinositol 3´-kinase inhibitor LY294002 completely blocked LPA-stimulated deoxyglucose uptake (IC50 ~2 μM). In marked contrast, wortmannin, which can completely block both insulin-like growth factor-I (IGF-I)-stimulated deGlc uptake in oocytes and phosphatidylinositol 3´-kinase activation at concentrations as low as 20 nM [Gould, Jess, Andrews, Herbst, Plevin and Gibbs (1994) J. Biol. Chem. 269, 26622–26625], was a relatively poor inhibitor of LPA-stimulated deGlc transport, even at concentrations as high as 100 nM. We further show that LPA stimulates phosphatidylinositol 3´-kinase activity(s) that can phosphorylate both phosphatidylinositol and phosphatidylinositol 4,5-bisphosphate, and that this stimulation is inhibited by LY294002 but is relatively insensitive to wortmannin, again in marked contrast to IGF-I-stimulated phosphatidylinositol 3´-kinase activity. Antibodies against the p85 regulatory subunit of phosphatidylinositol 3´-kinase or antiphosphotyrosine antibodies immunoprecipitated IGF-I-stimulated but not LPA-stimulated phosphatidylinositol 3´-kinase activity. We conclude that LPA stimulates glucose uptake in Xenopus oocytes by a mechanism that may involve activation of a form of phosphatidylinositol 3´-kinase that is distinguished from other isoforms by its resistance to wortmannin and by its substrate specificity. Since the LPA-activated form of phosphatidylinositol 3´-kinase is pharmacologically and immunologically distinct from that which is involved in IGF-I-stimulated glucose transport in these cells, we suggest that distinct isoforms of this enzyme are able to function with the same biological effect, at least in the regulation of sugar transport.

Long-chain n-3 polyunsaturated fatty acids dissociate phosphorylation of Akt from phosphatidylinositol 3′-kinase activity in rats

2007 ◽  
Vol 292 (4) ◽  
pp. E1223-E1230 ◽  
Author(s):  
Christelle Le Foll ◽  
Charlotte Corporeau ◽  
Valérie Le Guen ◽  
Jean-Paul Gouygou ◽  
Jean-Pascal Bergé ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Glucose Metabolism ◽  
Polyunsaturated Fatty Acids ◽  
Kinase Activity ◽  
Control Diet ◽  
Metabolizable Energy ◽  
Oral Glucose ◽  
Phosphatidylinositol 3 Kinase ◽  
Long Chain ◽  
Phosphatidylinositol 3

We examined whether a low amount of dietary long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) modulated phosphatidylinositol 3′-kinase (PI 3-kinase) activity and downstream Akt phosphorylation differently in normal or insulin-resistant rats. Rats were fed for 28 days with either a control diet containing 14.6% of metabolizable energy (ME) as peanut-rape oil (PR) or an n-3 diet where 4.9% of ME as PR was replaced by fish oil. Over the last 5 days, rats received 9‰ NaCl or dexamethasone (1 mg/kg). Insulin stimulation of both PI 3-kinase activity and Akt serine473 phosphorylation and modulation of GLUT4 content were studied in liver, muscle, and adipose tissue (AT). Glucose tolerance and insulin sensitivity were determined by an oral glucose challenge. In muscle and AT, LC n-3 PUFA abolished insulin-stimulated PI 3-kinase activity. These effects were not paralleled by defects in Akt serine473 phosphorylation, which was even increased in AT. Dexamethasone abolished insulin-stimulated PI 3-kinase activity in all tissues, whereas Akt serine473 phosphorylation was markedly reduced in muscle but unaltered in liver and AT. Such tissue-specific dissociating effects of LC n-3 PUFA on PI 3-kinase/Akt activation took place without alteration of glucose metabolism. Maintenance of a normal glucose metabolism by the n-3 diet despite abolition of PI 3-kinase activation was likely explained by a compensatory downstream Akt serine473 phosphorylation. The inability of LC n-3 PUFA to prevent insulin resistance by dexamethasone could result from the lack of such a dissociation.

High-fat diet and leptin treatment alter skeletal muscle insulin-stimulated phosphatidylinositol 3-kinase activity and glucose transport

Metabolism ◽  
2003 ◽  
Vol 52 (9) ◽  
pp. 1196-1205 ◽  
Author(s):  
Mohenish K Singh ◽  
Adam D Krisan ◽  
Andrew M Crain ◽  
Dale E Collins ◽  
Ben B Yaspelkis
Keyword(s):  
Skeletal Muscle ◽  
Glucose Transport ◽  
High Fat Diet ◽  
Kinase Activity ◽  
Phosphatidylinositol 3 Kinase ◽  
High Fat ◽  
Phosphatidylinositol 3

Possibility of distinct insulin-signaling pathways beyond phosphatidylinositol 3-kinase-mediating glucose transport and lipogenesis

Diabetes ◽  
1998 ◽  
Vol 47 (2) ◽  
pp. 179-185 ◽  
Author(s):  
R. W. Stevenson ◽  
D. K. Kreutter ◽  
K. M. Andrews ◽  
P. E. Genereux ◽  
E. M. Gibbs
Keyword(s):  
Signaling Pathways ◽  
Glucose Transport ◽  
Insulin Signaling ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3
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