Author/Editor | Hevener, Andrea L; Reichart, Donna; Janež, Andrej; Olefsky, Jerrold | |
Title | Thiazolidinedione treatment prevents free fatty acid-induced insulin resistance in male wistar rats | |
Type | članek | |
Source | Diabetes | |
Vol. and No. | Letnik 50, št. 10 | |
Publication year | 2001 | |
Volume | str. 2316-22 | |
Language | eng | |
Abstract | We sought to ascertain whether pretreatment with troglitazone (20 days) could prevent acute free fatty acid (FFA)-induced insulin resistance in male Wistar rats. Animals were divided into three groups: 1) control, 2) FFA infusion alone (FFA1), and 3) thiazolidinedione (TZD)-treated + FFA infusion (FFA1). Days before a hyperinsulinemic-euglycemic clamp, all animals were cannulated in the jugular vein (infusion) and carotid artery (sampling). Animals were allowed 5 days to recover from surgery and fasted 12 h before the experiment. Glucose (variable), insulin (40 mU. kg(-1). min(-1)), and Liposyn (heparinized 10% lipid emulsion) infusions were initiated simultaneously and continued from 0-120 min. Steady-state glucose, 8.3 +/- 0.14 mmol/l, and insulin concentrations, 7.3 +/- 2.45 nmol/l, were the same between groups. Interestingly, steady-state FFA levels were significantly lower in animals pretreated with TZD compared with FFA alone (1.83 +/- 0.26 vs. 2.96 +/- 0.25 mmol/l; P = 0.009), despite matched intralipid infusion rates. A second group of TZD-treated animals (TZD + FFA2) were infused with intralipid at a higher infusion rate (44%) to match the arterial concentrations of FFA1. The glucose infusion and insulin-stimulated glucose disposal rates (GDRs) were significantly decreased (40%) for untreated Liposyn infused (FFA1) compared with control rats. In addition, insulin receptor substrate-1 (IRS-1) phosphorylation and IRS-1-associated phosphatidylinositol (PI) 3-kinase activity was significantly reduced, 30-50%, in FFA1 rats. TZD pretreatment prevented the FFA-induced decrement in insulin signaling. Fatty acid translocase (FAT/CD36) also was significantly reduced (56%) in untreated FFA1 rats after the clamp but remained identical to control values for TZD-treated rats. In conclusion, acutely elevated FFA levels1) induced a significant reduction in tracer-determined GDR paralleled by impaired tyrosine phosphorylation of IRS-1(Abstract truncated at 2000 characters). | |
Descriptors | INSULIN RESISTANCE CHROMANS FATTY ACIDS, NONESTERIFIED LIVER THIAZOLES FAT EMULSIONS, INTRAVENOUS GLUCOSE INSULIN PHOSPHATIDYLINOSITOLS LIGANDS MEMBRANE GLYCOPROTEINS MUSCLE, SKELETAL PHOSPHOPROTEINS PHOSPHORYLATION RATS, WISTAR RECEPTORS, CYTOPLASMIC AND NUCLEAR TRANSCRIPTION FACTORS TYROSINE |