WILLIAM WINDER

..Thyroid state therefore appears to be one important factor controlling expression of these proteins in skeletal muscle...

..These observations lend credence to the hypothesis that AMPK activation induced by muscle contraction is responsible in part for adaptations to endurance exercise training...

..Because AMPK enhances both glucose uptake and fatty acid oxidation in skeletal muscle, it has become a target for prevention and treatment of type 2 diabetes and obesity...

..In addition, this system may have the capability of enhancing capacity for ATP production when the muscle is exposed to endurance training...

..These observations open the door to the possibility of treatment of patients with type 2 diabetes with AMPK activators...

..6 nmol/g. We conclude that AMPK activation can prevent high rates of glucose uptake and glycolytic flux from inhibiting palmitate oxidation in predominantly fast-twitch muscle under these conditions...

..These results suggest that chronic AMPK activation may mediate the effects of muscle contraction on some, but not all, biochemical adaptations of muscle to endurance exercise training...

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..Quantitative PCR revealed significantly reduced LKB1, MO25α, and STRADβ mRNA in LKB1(-/-) muscle. These findings demonstrate that the LKB1-MO25-STRAD complex is the principal AMPKK in skeletal muscle...

..Regardless, our results suggest that LKB1 is an important regulator of malonyl-CoA levels and fatty acid oxidation in skeletal muscle...

..We conclude that CREB and related proteins are direct downstream targets for AMPK and are therefore likely involved in mediating some effects of AMPK on expression of genes having a CRE in their promoters...

..saline-treated rats. These studies provide evidence that some effects of denervation may be prevented by chemical activation of the appropriate signaling pathways...

..These results suggest that the AMPK signaling cascade may directly sense and respond to the lipid energy charge of the cell...

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..These data provide evidence that skeletal muscle AMPK subunit and ACC expression is partially under the control of thyroid hormones...

..This may contribute to low-muscle malonyl-CoA values and increasing fatty acid oxidation rates during long-term exercise when plasma fatty acid concentrations are elevated...

..Capacity for voluntary running is compromised with muscle and heart LKB1 deficiency...

..Thus muscle ACC can be phosphorylated by PKA but with no apparent functional effects on the enzyme. AMPK appears to be the more important regulator of muscle ACC...

..These data provide evidence that thyroid hormones increase soleus muscle LKB1 and MO25 content with subsequent activation of AMPK, phosphorylation of CREB, and expression of mitochondrial protein genes having CRE in their promoters...

..Likewise, AMPK may regulate transport of FAs into the cell through FAT/CD36. AMPK may also regulate capacity for FA oxidation by phosphorylation of transcription factors such as CREB or coactivators such as PGC-1alpha...

..Thus, AMPK hyperactivation in response to contractile activity in aged fast-twitch muscle may be the result of compromised cellular energetics and not necessarily due to an inherent defect in responsiveness of the AMPK molecule per se...

..3-PG did not stimulate LKB1-STRAD-MO25 activity toward the peptide substrate LKB1tide. These results have identified 3-PG as an AMPK-specific regulator of AMPK phosphorylation and activation by LKB1-STRAD-MO25...

..05). In conclusion, endurance training markedly increased skeletal muscle LKB1 and MO25 protein without increasing AMPKK activity. LKB1 may be playing multiple roles in skeletal muscle adaptation to endurance training...

..The rapid decline in fructose 2,6-P2 probably plays a role in decreasing hepatic glycolysis, thereby ensuring that glucose 6-phosphate derived from glycogenolysis is diverted to blood glucose...

..After liver glycogen is depleted, epinephrine from the adrenal medulla prevents hypoglycemia and is essential for allowing continuation of exercise...

..In conclusion, these results suggest that creatine phosphate is not a direct regulator of LKB1 or AMPK activity. Creatine phosphate may indirectly modulate AMPK activity by replenishing ATP at the onset of muscle contraction...

..AMPK can phosphorylate GEF and in response to AICAR, GEF, and MEF2 translocate to the nucleus and have increased binding to the GLUT4 promoter...

..The increase in LKB1 and PGC-1alpha with endurance and interval training may function to maintain the training-induced increases in mitochondrial mass...

..These results suggest that AMPKK is activated during electrical stimulation of both trained and nontrained muscle by mechanisms other than covalent modification...

..There was a threefold increase in expression of gamma 3 after training in red quadriceps only. Our results suggest that gamma 3 might have a special role in the adaptation to endurance exercise in muscles utilizing oxidative metabolism...

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..The results will provide additional rationale for the use of regular exercise in preventing and treating type 2 diabetes and obesity. ..

..The proposed studies will provide additional rationale for convincing a predominantly sedentary population of the importance of regular exercise in combating inactivity-related diseases. ..

..These studies will contribute to our understanding of the mechanisms responsible for increasing fat utilization during exercise. ..

..This information will be important for better understanding the metabolic derangements of diabetes mellitus and for understanding regulation of fat utilization during exercise...

..The proposed studies will provide additional rationale for convincing a predominantly sedentary population of the importance of regular exercise in combating inactivity-related diseases. ..