Fredric Kraemer

Publication Details

  • Nordihydroguaiaretic acid improves metabolic dysregulation and aberrant hepatic lipid metabolism in mice by both PPAR alpha-dependent and -independent pathways AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY Zhang, H., Shen, W., Cortez, Y., Kraemer, F. B., Azhar, S. 2013; 304 (1): G72-G86

    Abstract:

    Creosote bush-derived nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, possesses antioxidant properties and functions as a potent antihyperlipidemic agent in rodent models. Here, we examined the effect of chronic NDGA treatment of ob/ob mice on plasma dyslipidemia, hepatic steatosis, and changes in hepatic gene expression. Feeding ob/ob mice a chow diet supplemented with either low (0.83 g/kg diet) or high-dose (2.5 g/kg diet) NDGA for 16 wk significantly improved plasma triglyceride (TG), inflammatory chemokine levels, hyperinsulinemia, insulin sensitivity, and glucose intolerance. NDGA treatment caused a marked reduction in liver weight and TG content, while enhancing rates of fatty acid oxidation. Microarray analysis of hepatic gene expression demonstrated that NDGA treatment altered genes for lipid metabolism, with genes involved in fatty acid catabolism most significantly increased. NDGA upregulated the mRNA and nuclear protein levels of peroxisome proliferator-activated receptor ? (PPAR?), and the activated (phosphorylated) form of AMP-activated kinase. NDGA increased PPAR? promoter activity in AML12 hepatocytes and also prevented the fatty acid suppression of PPAR? expression. In contrast, PPAR? siRNA abrogated the stimulatory effect of NDGA on fatty acid catabolism. Likewise, no stimulatory effect of NDGA on hepatic fatty acid oxidation was observed in the livers of PPAR?-deficient mice, but the ability of NDGA to reverse fatty liver conditions was unaffected. In conclusion, the beneficial actions of NDGA on dyslipidemia and hepatic steatosis in ob/ob mice are exerted primarily through enhanced fatty acid oxidation via PPAR?-dependent pathways. However, PPAR?-independent pathways also contribute to NDGA's action to ameliorate hepatic steatosis.

    View details for DOI 10.1152/ajpgi.00328.2012

    View details for Web of Science ID 000313040500008

    View details for PubMedID 23104557

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