Impaired Insulin Action on Phosphatidylinositol 3-Kinase Activity and Glucose Transport in Skeletal Muscle of Pancreatic Cancer Patients

Pancreas ◽  
2003 ◽  
Vol 26 (2) ◽  
pp. 173-177 ◽  
Author(s):  
Bengt Isaksson ◽  
Lisa Strömmer ◽  
Helmut Friess ◽  
Markus W. Büchler ◽  
Margery K. Herrington ◽  
...  
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

Endocrinology ◽  
1999 ◽  
Vol 140 (9) ◽  
pp. 4244-4250 ◽  
Author(s):  
Denis Furling ◽  
André Marette ◽  
Jack Puymirat

Abstract Primary human skeletal muscle cell cultures derived from muscles of a myotonic dystrophy (DM) fetus provided a model in which both resistance to insulin action described in DM patient muscles and the potential ability of insulin-like growth factor I (IGF-I) to circumvent this defect could be investigated. Basal glucose uptake was the same in cultured DM cells as in normal myotubes. In DM cells, a dose of 10 nm insulin produced no stimulatory effect on glucose uptake, and at higher concentrations, stimulation of glucose uptake remained significantly lower than that in normal myotubes. In addition, basal and insulin-mediated protein synthesis were both significantly reduced compared with those in normal cells. In DM myotubes, insulin receptor messenger RNA expression and insulin receptor binding were significantly diminished, whereas the expression of GLUT1 and GLUT4 glucose transporters was not affected. These results indicate that impaired insulin action is retained in DM cultured myotubes. The action of recombinant human IGF-I (rhIGF-I) was evaluated in this cellular model. We showed that rhIGF-I is able to stimulate glucose uptake to a similar extent as in control cells and restore normal protein synthesis level in DM myotubes. Thus, rhIGF-I is able to bypass impaired insulin action in DM myotubes. This provides a solid foundation for the eventual use of rhIGF-I as an effective treatment of muscle weakness and wasting in DM.


1996 ◽  
Vol 316 (1) ◽  
pp. 161-166 ◽  
Author(s):  
Fiona J. THOMSON ◽  
Colin MOYES ◽  
Pamela H. SCOTT ◽  
Robin PLEVIN ◽  
Gwyn W. GOULD

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.


1993 ◽  
Vol 265 (5) ◽  
pp. E736-E742 ◽  
Author(s):  
K. S. Chen ◽  
J. C. Friel ◽  
N. B. Ruderman

The presence of phosphatidylinositol 3-kinase (PI 3-kinase) in mammalian skeletal muscle and its response to insulin stimulation were investigated. PI kinase, immunoprecipitated from rat soleus muscle with antibodies directed toward its 85-kDa subunit phosphorylated PI, phosphatidylinositol 4-phosphate [PI(4)P], and phosphatidylinositol 4,5,-bisphosphate [PI(4,5)P2] to yield phosphatidylinositol 3-phosphate [PI(3)P], phosphatidylinositol 3,4,-bisphosphate, and phosphatidylinositol trisphosphate in vitro. PI 3-kinase activity was also immunoprecipitated with antiphosphotyrosine [alpha-Tyr(P)] antibodies and with antibodies raised against IRS-1, a substrate of the insulin receptor protein tyrosine kinase that associates with and activates PI 3-kinase. Incubation of the soleus with insulin in vitro, or injection of insulin into rats in vivo, produced three- to fivefold increases in alpha-Tyr(P)- and alpha-IRS-1-immunoprecipitable PI 3-kinase activity. In nonstimulated soleus muscle, PI 3-kinase activity immunoprecipitated with alpha-IRS-1 or with alpha-Tyr(P) antibodies was evenly distributed between particulate (200,000-g pellet) and soluble fractions. Insulin treatment increased immunoprecipitable PI 5-kinase activity in both fractions, but the increase in alpha-Tyr-(P)-precipitable activity was greater in the particulate fraction, whereas the increase in alpha-IRS-1-precipitable activity was greater in the soluble fraction. In intact soleus muscles incubated with 32PO4, insulin increased the labeling of PI(3)P but did not affect the labeling of PI(4)P or PI(4,5)P2. Activation of PI 3-kinase by insulin was unaffected by prior denervation of the muscle, a manipulation that has been shown to cause both insulin resistance and hypersensitivity in muscles, depending on the parameter measured.(ABSTRACT TRUNCATED AT 250 WORDS)


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