Bezafibrate at Clinically Relevant Doses Decreases Serum/Liver Triglycerides via Down-Regulation of Sterol Regulatory Element-Binding Protein-1c in Mice: A Novel Peroxisome Proliferator-Activated Receptor α-Independent Mechanism
| Autor: | Yuji Kamijo, Atsushi Hara, Hiroki Kanbe, Xiaowei Zhang, Naoki Tanaka, Toshifumi Aoyama, Takero Nakajima, Frank J. Gonzalez |
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| Rok vydání: | 2009 |
| Předmět: |
Male
medicine.medical_specialty Down-Regulation Peroxisome proliferator-activated receptor Biology Mice Random Allocation chemistry.chemical_compound Pharmacokinetics Internal medicine medicine Animals Humans PPAR alpha Receptor Triglycerides Mice Knockout Pharmacology chemistry.chemical_classification Bezafibrate Dose-Response Relationship Drug Triglyceride Fatty acid Articles Sterol regulatory element-binding protein Endocrinology Liver chemistry Molecular Medicine Sterol Regulatory Element Binding Protein 1 medicine.drug |
| Zdroj: | Molecular Pharmacology. 75:782-792 |
| ISSN: | 1521-0111 0026-895X |
| Popis: | The triglyceride-lowering effect of bezafibrate in humans has been attributed to peroxisome proliferator-activated receptor (PPAR) alpha activation based on results from rodent studies. However, the bezafibrate dosages used in conventional rodent experiments are typically higher than those in clinical use (or =50 versusor =10 mg/kg/day), and thus it remains unclear whether such data can be translated to humans. Furthermore, because bezafibrate is a pan-PPAR activator, the actual contribution of PPARalpha to its triglyceride-lowering properties remains undetermined. To address these issues, bezafibrate at clinically relevant doses (10 mg/kg/day; low) was administered to wild-type and Ppara-null mice, and its effects were compared with those from conventionally used doses (100 mg/kg/day; high). Pharmacokinetic analyses showed that maximum plasma concentration and area under the concentration-time curve in bezafibrate-treated mice were similar to those in humans at low doses, but not at high doses. Low-dose bezafibrate decreased serum/liver triglycerides in a PPARalpha-independent manner by attenuation of hepatic lipogenesis and triglyceride secretion. It is noteworthy that instead of PPAR activation, down-regulation of sterol regulatory element-binding protein (SREBP)-1c was observed in mice undergoing low-dose treatment. High-dose bezafibrate decreased serum/liver triglycerides by enhancement of hepatic fatty acid uptake and beta-oxidation via PPARalpha activation, as expected. In conclusion, clinically relevant doses of bezafibrate exert a triglyceride-lowering effect by suppression of the SREBP-1c-regulated pathway in mice and not by PPARalpha activation. Our results may provide novel information about the pharmacological mechanism of bezafibrate action and new insights into the treatment of disorders involving SREBP-1c. |
| Databáze: | OpenAIRE |
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