Alternate-Day High-Fat Diet Induces an Increase in Mitochondrial Enzyme Activities and Protein Content in Rat Skeletal Muscle.

Takuji Kawamura,Mitsuru Higuchi,Kazuhiko Higashida,Xi Li

doi:10.3390/nu8040203

Takuji Kawamura, Mitsuru Higuchi + Show 2 more

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https://doi.org/10.3390/nu8040203

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Journal: Nutrients	Publication Date: Apr 6, 2016
Citations: 50	License type: CC BY 4.0

Affiliation: Waseda University, University of Shiga Prefecture

Abstract

Long-term high-fat diet increases muscle mitochondrial enzyme activity and endurance performance. However, excessive calorie intake causes intra-abdominal fat accumulation and metabolic syndrome. The purpose of this study was to investigate the effect of an alternating day high-fat diet on muscle mitochondrial enzyme activities, protein content, and intra-abdominal fat mass in rats. Male Wistar rats were given a standard chow diet (CON), high-fat diet (HFD), or alternate-day high-fat diet (ALT) for 4 weeks. Rats in the ALT group were fed a high-fat diet and standard chow every other day for 4 weeks. After the dietary intervention, mitochondrial enzyme activities and protein content in skeletal muscle were measured. Although body weight did not differ among groups, the epididymal fat mass in the HFD group was higher than those of the CON and ALT groups. Citrate synthase and beta-hydroxyacyl CoA dehydrogenase activities in the plantaris muscle of rats in HFD and ALT were significantly higher than that in CON rats, whereas there was no difference between HFD and ALT groups. No significant difference was observed in muscle glycogen concentration or glucose transporter-4 protein content among the three groups. These results suggest that an alternate-day high-fat diet induces increases in mitochondrial enzyme activities and protein content in rat skeletal muscle without intra-abdominal fat accumulation.

Highlights

Endurance exercise training induces an increase in mitochondrial content in skeletal muscle [1], resulting in increased capacity of muscles to regenerate ATP
The 4-week high-fat diet resulted in an increase in epididymal fat weight in the HFD group (CON vs. HFD, p < 0.05)
It was first reported by Holloszy [1] that endurance exercise training increases mitochondrial enzyme activities in rat skeletal muscle, and this finding was confirmed by other research groups assessing human skeletal muscle [22]

Summary

Introduction

Endurance exercise training induces an increase in mitochondrial content in skeletal muscle [1], resulting in increased capacity of muscles to regenerate ATP. The increase in muscle mitochondrial content results in a change in substrate utilization—with increased fat oxidation and decreased utilization of muscle glycogen [2,3]. Demonstrated that a 5-week high-fat diet in rats elevated mitochondrial enzyme activities in skeletal muscle. This biochemical adaptation in skeletal muscle has been reported by other groups in rodents and human subjects [5,6,7,8], other groups reported opposite results, which high-fat diet feeding

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