A High-Fat Diet Has a Tissue-Specific Effect on Adiponectin and Related Enzyme Expression

Authors

  • Maayan Barnea,

    1. The Hebrew University of Jerusalem, Faculty of Agricultural, Food and Environmental Quality Sciences, Institute of Biochemistry, Food Science and Nutrition, Rehovot, Israel
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  • Avi Shamay,

    1. Volcani Center, Agricultural Research Organization, Institute of Animal Science, Bet Dagan, Israel.
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  • Aliza H. Stark,

    1. The Hebrew University of Jerusalem, Faculty of Agricultural, Food and Environmental Quality Sciences, Institute of Biochemistry, Food Science and Nutrition, Rehovot, Israel
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  • Zecharia Madar

    Corresponding author
    1. The Hebrew University of Jerusalem, Faculty of Agricultural, Food and Environmental Quality Sciences, Institute of Biochemistry, Food Science and Nutrition, Rehovot, Israel
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The Hebrew University of Jerusalem, Faculty of Agricultural, Food and Environmental Quality Sciences, Institute of Biochemistry, Food Science and Nutrition, P.O. Box 12, Rehovot, 76100 Israel. E-mail: Madar@agri.huji.ac.il

Abstract

Objective: This study was designed to test whether adiponectin plays a role in diet-induced obesity and insulin resistance and acts as a mediator to induce or inhibit specific metabolic pathways involved in lipid metabolism

Research Methods and Procedures: Forty C57BL/6J male mice were fed either a high-fat (HF) or control diet for 4 months, and adiponectin, its receptors, and enzyme expression in liver and muscle tissue were measured.

Results: Mice fed the HF diet exhibited significantly greater weight gain, abnormal oral glucose tolerance test curves, and elevated homeostasis model assessment of insulin resistance (5.3 ± 0.89 vs. 2.8 ± 0.39). A significant reduction of adiponectin RNA expression (51%) and protein levels (15%) was observed in the adipose tissue of HF animals; however, serum adiponectin levels did not differ between groups (7.12 ± 0.34 μg/mL vs. 6.44 ± 0.38 μg/mL). Expression of hepatic mRNA of AdipoR1 and AdipoR2 was reduced by 15% and 25%, respectively, in animals fed the HF diet. In contrast, receptor mRNA expression of AdipoR1 and AdipoR2 increased by 25% and 30%, respectively, in muscle tissue. No effect was found on hepatic adenosine monophosphate-activated protein kinase expression; however, a significant reduction of phosphoadenosine monophosphate kinase levels in muscles was observed. Hepatic acetyl-coenzyme A carboxylase was similar between groups, but in muscles, the inactive form phosphoacetyl-coenzyme A carboxylase was significantly reduced (p < 0.05).

Discussion: The HF diet led to decreased insulin sensitivity accompanied by impaired activity of adiponectin-related enzymes in skeletal muscles but not in the liver. These results suggest that the HF diet has a tissue-specific effect on adiponectin and associated enzyme expression.

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