GLUT4 content decreases along with insulin resistance and high levels of inflammatory markers in rats with metabolic syndrome

• Main Authors: Leguisamo Natalia M, Lehnen Alexandre M, Machado Ubiratan F, Okamoto Maristela M, Markoski Melissa M, Pinto Graziela H, Schaan Beatriz D
• Format: Article
• Language: English
• Published: BMC 2012-08-01
• Series: Cardiovascular Diabetology
• Subjects: Monosodium glutamate; Spontaneously hypertensive rats; Glucose transporter 4
• Online Access: http://www.cardiab.com/content/11/1/100

<p>Abstract</p> <p>Background</p> <p>Metabolic syndrome is characterized by insulin resistance, which is closely related to GLUT4 content in insulin-sensitive tissues. Thus, we evaluated the GLUT4 expression, insulin resistance and inflammation, characteristics of the metabolic syndrome, in an experimental model.</p> <p>Methods</p> <p>Spontaneously hypertensive neonate rats (18/group) were treated with monosodium glutamate (MetS) during 9 days, and compared with Wistar-Kyoto (C) and saline-treated SHR (H). Blood pressure (BP) and lipid levels, C-reactive protein (CRP), interleukin 6 (IL-6), TNF-α and adiponectin were evaluated. GLUT4 protein was analysed in the heart, white adipose tissue and gastrocnemius. Studies were performed at 3 (3-mo), 6 (6-mo) and 9 (9-mo) months of age.</p> <p>Results</p> <p>MetS rats were more insulin resistant (p<0.001, all ages) and had higher BP (3-mo: p<0.001, 6-mo: p = 0.001, 9-mo: p = 0.015) as compared to C. At 6 months, CRP, IL-6 and TNF-α were higher (p<0.001, all comparisons) in MetS rats <it>vs</it> H, but adiponectin was lower in MetS at 9 months (MetS: 32 ± 2, H: 42 ± 2, C: 45 ± 2 pg/mL; p<0.001). GLUT4 protein was reduced in MetS as compared to C rats at 3, 6 and 9-mo, respectively (Heart: 54%, 50% and 57%; Gastrocnemius: 37%, 56% and 50%; Adipose tissue: 69%, 61% and 69%).</p> <p>Conclusions</p> <p>MSG-treated SHR presented all metabolic syndrome characteristics, as well as reduced GLUT4 content, which must play a key role in the impaired glycemic homeostasis of the metabolic syndrome.</p>