ABSTRACT
Introduction...................................................................................................... 496 Role of Skeletal Muscle Fatty Acid Metabolism in the Genesis of Insulin Resistance .................................................................................... 496 Glucose-Fatty Acid Cycle ........................................................................... 497 Increased Intramyocellular Triglyceride Accumulation............................... 497 Decreased Skeletal Muscle Lipolysis in Insulin Resistance........................ 499 Impaired Mitochondrial Function in Insulin Resistance ............................. 500
Adenosine Monophosphate-Activated Protein Kinase .................................... 501 AMPK: Structure, Regulation, and Functions............................................. 501 AMPK and Metabolic Syndrome ................................................................ 502 Roles of AMPK in Peripheral Tissues......................................................... 503 Skeletal Muscle ........................................................................................ 503 Liver ......................................................................................................... 503 Vascular Endothelial Cell ........................................................................ 505 Pancreatic Islet b-Cells ............................................................................ 505
Role of AMPK in the Hypothalamus .......................................................... 505 Nutrient Sensing in the Hypothalamus and Feeding Regulation ............ 505
Role of Hypothalamic AMPK in Regulating Food Intake and Energy Expenditure....................................................................... 506
LA and Metabolic Syndrome .......................................................................... 508 Beneficial Effect of LA in Metabolic Syndrome......................................... 508 Effect of LA on AMPK in Peripheral Tissues ............................................ 509 Skeletal Muscle ........................................................................................ 509 Pancreatic Islet b-Cells ............................................................................ 509 Vascular Endothelial Cell ........................................................................ 509 ALA, AMPK, and Antioxidant Action.................................................... 509
Effect of LA on AMPK in the Hypothalamus ............................................ 510 Conclusion ....................................................................................................... 511 References ........................................................................................................ 511
Metabolic syndrome is a cluster of cardiovascular risk factors, including abdominal obesity, glucose intolerance, dyslipidemia, and hypertension [1]. The incidence of metabolic syndrome is increasing, and it is estimated to affect 15%–30% of individuals in industrialized countries [2]. The metabolic syndrome is associated with a two-to four-fold increase in cardiovascular morbidity and mortality, and a five-to nine-fold increase in the risk of developing type 2 diabetes mellitus [3,4]. Although life style modifications (e.g., exercise and calorie restriction to reduce weight) are considered first-line therapy for metabolic syndrome, they are often ineffective by themselves.
