Insulin-like and non-insulin-like selenium actions in 3T3-L1 adipocytes

✍ Scribed by Emma Heart; Chin K. Sung

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 201 KB
• Volume: 88
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.10395

✦ Synopsis

Abstract

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. © 2002 Wiley‐Liss, Inc.