- Increase in Fatty Acid Oxidation by AICAR: the Role of p38 MAPK.
-
Woo Je Lee, Jin Yob Kim, Sung Jin Bae, Eun Hee Koh, Sung Min Han, Hye Sun Park, Hyun Sik Kim, Min Seon Kim, Joong Yeol Park, Ki Up Lee
-
Korean Diabetes J. 2005;29(1):15-21. Published online January 1, 2005
-
-
-
 Abstract
 PDF
- BACKGROUND
AMPK is an enzyme that increases glucose transport and fatty acid oxidation in skeletal muscle. The activation of AMPK stimulates fatty acid oxidation by decreasing the acetyl CoA carboxylase (ACC) activity and the concentration of malonyl-CoA. However, a recent study has reported a dissociation of AMPK activity and ACC phosphorylation in skeletal muscle during periods of prolonged exercise. This suggested that there is an additional mechanism for AMPK-induced fatty acid oxidation in skeletal muscle. METHODS: Plamitate oxidation was measured via the generation of [3H]-water generation from 9,10[3H]-palmitate after treating various concentrations of AICAR on the C2C12 mouse skeletal muscle cell line. Western analysis was used to test for the possible activation of p38 MAPK by AICAR. Involvement of p38 MAPK in the AICAR-induced increase in fatty acid oxidation was tested for by using SB203580, a p38 MAPK inhibitor. RESULTS: C2C12 cell treated with AICAR exhibited a dose-dependent increase in fatty acid oxidation compared to the cells that were not treated with AICAR. Western blot analysis revealed that phosphorylation of p38 MAPK was increased 2.5 folds after AICAR treatment. The increase of fatty acid oxidation with AICAR treatment was significantly inhibited by a treatment of SB203580; this indicated the involvement of p38 MAPK on the AICAR-induced increase in fatty acid oxidation. CONCLUSION: AICAR stimulated the fatty acid oxidation by activating p38 MAPK. This is a novel pathway by which AMPK activation in skeletal muscle increases the fatty acid oxidation
- AMPK Activator AICAR Inhibits Hepatic Gluconeogenesis and Fatty Acid Oxidation.
-
Jin Yob Kim, Eun Hee Koh, Woo Je Lee, Seong Min Han, Ji Young Youn, Hye Sun Park, Hyun Sik Kim, Min Seon Kim, Joong Yeol Park, Ki Up Lee
-
Korean Diabetes J. 2005;29(1):6-14. Published online January 1, 2005
-
-
-
Abstract
PDF
- BACKGROUND
Recent studies have demonstrated that adiponectin and metformin activate AMPK in the liver, and adiponectin and metformin stimulate fatty acid oxidation while inhibiting glucose production in liver. These results are in contrast to previous studies that have demonstrated that increased fatty acid oxidation in the liver is associated with increased gluconeogenesis. The present study was undertaken to reinvestigate the effects of AMPK activation by AICAR on hepatic fatty acid oxidation and gluconeogenesis. METHODS: HePG2 cells were treated with various concentrations of AICAR, and then the fatty acid oxidation and gluconeogenesis of the cells were determined. To investigate the in vivo effect of AICAR, Sprague-Dawely rats were infused with AICAR (bolus, 40 mg/g; constant, 7.5 mg/g/min-1) for 90min. RESULTS: Incubation of the HePG2 cells with higher concentrations (=1 mM) of AICAR increased fatty acid oxidation and gluconeogenesis. On the other hand, incubation of HePG2 cells with lower concentrations (0.05 and 0.1 mM) of AICAR decreased fatty acid oxidation and gluconeogenesis. Consistent with this in vitro data, the intravenous administration of AICAR to rats lowered their plasma glucose concentration and inhibited hepatic gluconeogenesis. Fatty acid oxidation in the liver tissue was significantly decreased by the administration of AICAR. CONCLUSION: The present study has demonstrated that AICAR decreased gluconeo-genesis in the liver. In contrast to previous studies, AICAR profoundly decreased hepatic fatty acid oxidation in rats and also in cultured hepatocytes
- The Role of AMPK in Vascular Endothelium.
-
Woo Je Lee, Jin Yob Kim, Eun Hee Koh, Sung Min Han, Min Seon Kim, Ki Up Lee, Joong Yeol Park
-
Korean Diabetes J. 2005;29(1):1-5. Published online January 1, 2005
-
-
-
Abstract
PDF
- No abstract available.
|
KDA
