Insulin-like and non-insulin-like selenium actions in 3T3-L1 adipocytes.
In insulin-sensitive 3T3-L1 adipocytes, selenium stimulates glucose transport and antilipolysis and these actions of selenium, like insulin actions, are sensitive to wortmanin, an inhibitor of phosphatidylinositol-3-kinase (PI3K). Selenium stimulates PI3K activity that is sustained up to 24 h. Selenium after 5-10 min increases tyrosine phosphorylation of selective cellular proteins, but after 24 h overall tyrosine phosphorylation is increased. Tyrosine phosphorylation of insulin receptor substrate 1 is detected when enriched by immunoprecipitation with anti-PI3K antibody. Selenium, however, does not stimulate insulin receptor tyrosine kinase activity. Selenium also increases phosphorylation of other insulin signaling proteins, including Akt and extracellular signal regulated kinases. Selenium-stimulated glucose transport is accompanied by increases in glucose transporter-1 content in the plasma membrane. These data are consistent with similar selenium action in glucose transport in 3T3-L1 fibroblasts expressing mainly GLUT1. In chronic insulin-induced insulin resistant cells, selenium unlike insulin fully stimulates glucose transport. In summary, selenium stimulates glucose transport and antilipolysis in a PI3K-dependent manner, but independent of insulin receptor activation. Selenium exerts both insulin-like and non-insulin-like actions in cells.
Heart
Emma
E
Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, California 90089-9142, USA.
Sung
Chin K
CK
D016475:3T3 Cells; D017667:Adipocytes; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003847:Deoxyglucose / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D051272:Glucose Transporter Type 1; D007328:Insulin / Q000494:pharmacology / Q000502:physiology; D007329:Insulin Antagonists / Q000494:pharmacology; D008066:Lipolysis / Q000187:drug effects / Q000502:physiology; D051379:Mice; D009004:Monosaccharide Transport Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation / Q000187:drug effects; D012643:Selenium / Q000494:pharmacology / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D000077191:Wortmannin
D000730:Androstadienes; D003847:Deoxyglucose; D004791:Enzyme Inhibitors; D005947:Glucose; D051272:Glucose Transporter Type 1; D007328:Insulin; D007329:Insulin Antagonists; D009004:Monosaccharide Transport Proteins; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D012643:Selenium; D000077191:Wortmannin; C495678:Slc2a1 protein, mouse