In:
American Journal of Physiology-Endocrinology and Metabolism, American Physiological Society, Vol. 292, No. 4 ( 2007-04), p. E1213-E1222
Abstract:
A clinically employed antihyperlipidemic drug, bezafibrate, has been characterized as a PPAR(α, -γ, and -δ) pan-agonist in vitro. Recent extended trials have highlighted its antidiabetic properties in humans. However, the underlying molecular mechanism is not fully elucidated. The present study was designed to explore potential regulatory mechanisms of intracellular glucocorticoid reactivating enzyme, 11β-HSD1 and anti-diabetic hormone, adiponectin by bezafibrate in murine adipose tissue, and cultured adipocytes. Treatment of db/db mice with bezafibrate significantly ameliorated hyperglycemia and insulin resistance, accompanied by a marked reduction of triglyceride and nonesterified fatty acids. Despite equipotent in lipid-lowering effects, another fibrate, fenofibrate, did not show such beneficial effects on glycemic control. Treatment of bezafibrate caused a marked decrease in the mRNA level of 11β-HSD1 preferentially in adipose tissue of db/db mice (−47%, P 〈 0.05), concomitant with a significant increase in plasma adiponectin level (+37%, P 〈 0.01). Notably, treatment of bezafibrate caused a marked decrease in the mRNA level (−34%, P 〈 0.01) and enzyme activity (−32%, P 〈 0.01) of 11β-HSD1, whereas the treatment substantially augmented the expression (+71%, P 〈 0.01) and secretion (+27%, P 〈 0.01) of adiponectin in 3T3-L1 adipocytes. Knockdown of 11β-HSD1 by siRNA confirmed that 11β-HSD1 acts as a distinct oxoreductase in adipocytes and validated the enzyme activity assays in the present study. Effects of bezafibrate on regulation of 11β-HSD1 and adiponectin in murine adipocytes were comparable with those in thiazolidinediones. This is the first demonstration that bezafibrate directly regulates 11β-HSD1 and adiponectin in murine adipocytes, both of which may contribute to metabolically-beneficial effects by bezafibrate.
Type of Medium:
Online Resource
ISSN:
0193-1849
,
1522-1555
DOI:
10.1152/ajpendo.00340.2006
Language:
English
Publisher:
American Physiological Society
Publication Date:
2007
detail.hit.zdb_id:
1477331-4
SSG:
12
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