Effects of Endurance Exercise and High-Fat Diet on Insulin Resistance and Ceramide Contents of Skeletal Muscle in Sprague-Dawley Rats.
10.4093/kdj.2010.34.4.244
- Author:
Hyun Lyung JUNG
1
;
Ho Youl KANG
Author Information
1. Exercise Metabolism Laboratory, Department of Physical Education, Kyungpook National University, Daegu, Korea. hokang@knu.ac.kr
- Publication Type:Original Article
- Keywords:
Ceramides;
Glucose transport rate;
Glucose transporter type 4;
High-fat diet;
Insulin resistance
- MeSH:
Animals;
Ceramides;
Diet, High-Fat;
Glucose;
Glucose Transport Proteins, Facilitative;
Glucose Transporter Type 4;
Insulin;
Insulin Resistance;
Muscle, Skeletal;
Muscles;
Plasma;
Rats;
Rats, Sprague-Dawley;
Triglycerides
- From:Korean Diabetes Journal
2010;34(4):244-252
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND: We evaluated the effects of endurance exercise and a high-fat diet on insulin resistance and ceramide contents of skeletal muscle in Sprague-Dawley rats. METHODS: We randomly divided 32 rats into four groups: control (CON, n = 8), high fat diet (HF, n = 8), exercise (Ex, 24 m/min for 2 hours, 5 days/wk, n = 8), HF/Ex (n = 8). After 4-week treatments, plasma lipid profiles, glucose and insulin concentrations were measured. The triglycerides (TG), ceramide, and glucose transporter 4 (GLUT-4) contents were measured in the skeletal muscle. The rate of glucose transport was determined under submaximal insulin concentration during the muscle incubation. RESULTS: Free fatty acid levels were significantly higher in CON and HF than Ex (P = 0.032). Plasma glucose levels in HF were significantly higher than the two Ex groups (P = 0.002), and insulin levels were significantly higher in HF than in other three groups (P = 0.021). Muscular TG concentrations were significantly higher in HF than CON and Ex and also in HF/Ex than Ex, respectively (P = 0.005). Hepatic TG concentrations were significantly higher in HF than other three groups but Ex was significantly lower than HF/Ex (P = 0.000). Muscular ceramide content in HF was significantly greater than that in either Ex or HF/Ex (P = 0.031). GLUT-4 levels in CON and HF were significantly lower than those in Ex and HF/Ex (P = 0.009, P = 0.003). The glucose transport rate in submaximal insulin concentration was lower in CON than in either Ex or HF/Ex (P = 0.043), but not different from HF. CONCLUSION: This study suggests that high fat diet for 4 weeks selectively impairs insulin resistance, but not glucose transport rate, GLUT-4 and ceramide content in skeletal muscle per se. However, endurance exercise markedly affects the content of ceramide and insulin resistance in muscle.
