Organismal Carbohydrate and Lipid Homeostasis

All living organisms maintain a high ATP:ADP ratio to drive energy-requiring processes.They therefore need mechanisms to maintain energy balance at the cellular level.In addition, multicellular eukaryotes have assigned the task of storing energy to specialized cells such as adipocytes, and therefore also need a means of intercellular communication to signal the needs of individual tissues and to maintain overall energy balance at the whole body level.Such signaling allows animals to survive periods of fasting or starvation when food is not available and is mainly achieved by hormonal and nervous communication.Insulin, adipokines, epinephrine, and other agonists thus stimulate pathways that regulate the activities of key enzymes involved in control of metabolism to integrate organismal carbohydrate and lipid metabolism.Overnutrition can dysregulate these pathways and have damaging consequences, causing insulin resistance and type 2 diabetes.Outline 1 Introduction 2 Maintaining energy homeostasishormones and adipokines 3 Muscle-acute activation of glycogen breakdown 4 Muscle-acute regulation of glucose uptake and glycogen synthesis 5 Muscle-acute regulation of fatty acid oxidation 6 Muscle-long-term adaptation to exercise 7 Liver-acute regulation of carbohydrate metabolism 8 Liver-long-term regulation of gluconeogenesis via effects on gene expression 9 Liver-regulation of fatty acid, triglyceride, and cholesterol metabolism 10 Adipocytes-regulation of fatty acid metabolism 11 Brown adipocytes-regulation of fatty acid oxidation and heat production 12 Insulin resistance and type 2 diabetesa response to overnutrition? 13 Concluding