High-fructose diet preserves [beta ]-cell mass and prevents diabetes in nonobese diabetic mice: A potential role for increased insulin receptor substrate-2 expression

Abstract

We demonstrate that a high-fructose diet reduces the incidence of diabetes in nonobese diabetic (NOD) mice (31.2% v 57.1% on regular chow (RC); P = .009). In a second cohort of mice, we evaluated potential mechanisms for the protective effect of the high-fructose (HF) diet and whether the metabolic changes are strain-specific. Sixty NOD and 60 Balb/c mice were randomized at weaning into HF- and RC-fed groups (30 mice each) and followed for 28 weeks. Glucose tolerance testing demonstrated improved glucose tolerance in HF diet groups (P = .001 in Balb/c; P = .04 in NOD mice at 6 months). [beta ]-cell mass was preserved in NOD mice on the HF diet, but remained unchanged in Balb/c mice. In NOD mice, hepatic insulin receptor substrate (IRS)-2 protein expression increased by 2-fold (P = .01 for 2 v 6 months) in HF-fed mice and was 53% [plusmn] 15% higher (P = .01) in the HF diet versus RC groups at 6 months of age. IRS-2 expression was also increased in skeletal muscle of NOD mice and in both liver and muscle of Balb/c mice. Our data suggest that a HF diet improves glucose tolerance in both NOD and Balb/c mice. The improved glucose tolerance may be related to increased IRS-2 expression and, in NOD mice, preservation of [beta ]-cell mass.