Dietary glycemic index does not influence prooxidant and antioxidant gene expression in adipose tissue of C57BL/6 mice

Abstract

The objective of this study was to determine whether a high glycemic index (H‐GI) diet compared to a low glycemic index (L‐GI) diet alters prooxidant and antioxidant gene expression in adipose tissue of mice. C57BL/6 mice (n=8/grp) were fed a diet containing either H‐GI starch (100% amylopectin) or L‐GI starch (60% amylose/40% amylopectin) under low fat (LF) or high fat (HF) conditions for 15 weeks. Meal tolerance tests (MTT) were performed to determine blood glucose response to the experimental diets. The expression of the prooxidant enzyme NADPH oxidase (NOX) and antioxidant enzymes glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD) was determined by real‐time PCR. In both the LF and HF groups, the area under the blood glucose curve for the MTT was significantly greater (P<0.03) in mice fed H‐GI compared to L‐GI. The HF fed mice had a significant increase (P=0.0005) in NOX expression compared to the LF fed mice. There was no significant difference in NOX expression between H‐GI and L‐GI diet groups. HF diet feeding significantly decreased (P=0.004) the expression of GPx compared to LF feeding. There was no significant difference in GPx expression between H‐GI and L‐GI diet groups. The expression of CAT and SOD was not different among any of the diet groups. Diets differing in GI do not influence prooxidant and antioxidant enzyme gene expression in adipose tissue of mice. (Funded by AAES 080‐025)