Effects of α-tocopherol supplementation on dexamethasone-induced insulin resistance

• Author / Creator

  Williams, Deon

• This study aimed to examine potential mechanisms for glucocorticoid (GC)-induced decreases in glucose clearance, and to determine if a reduction in oxidative stress load via dietary pre-treatment with an antioxidant-rich diet has a positive net effect on glucose tolerance following a sub-chronic treatment with the GC analogue dexamethasone (DEX). Rats fed a diet supplemented with 700IU of α-tocopherol for two weeks had improved glucose clearance after five days of DEX-treatment relative to unsupplemented rats as well as decreased markers of oxidative stress. Following an intraperitoneal bolus of insulin, phosphorylation of AMP activated protein kinase (AMPK) was preserved in the supplemented groups despite no significant differences in upstream insulin signalling cascade intermediates between DEX-treated groups. This was corroborated by a similar increase (p<0.05) in phosphorylation of the downstream AMPK substrate acetyl CoA carboxylase. This study demonstrated that α-tocopherol supplementation can attenuate GC-induced decreases in glucose clearance in an AMPK-dependent manner.

• Subjects / Keywords

  • Glucocorticoid
  • Insulin resistance
  • Tocopherol
  • Glucose clearance
  • AMPK
  • Dexamethasone

• Graduation date

  Fall 2010

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3WM6D

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.