Sensory and Metabolic Control of Energy Balance

During the last two decades, the prevalence of obesity has dramatically increased in western and westernized societies. Its devastating health consequences include hypertension, cardiovascular diseases, or diabetes and make obesity the second leading cause of unnecessary deaths in the USA. As a consequence, obesity has a strong negative impact on the public health care systems. Recently emerging scienti?c insight has helped understanding obesity as a complex chronic disease with multiple causes. A multileveled gene–environment interaction appears to involve a substantial number of susceptibility genes, as well as associations with low physical activity levels and intake of high-calorie, low-cost, foods. Unfor- nately, therapeutic options to prevent or cure this disease are extremely limited, posing an extraordinary challenge for today’s biomedical research community. Obesity results from imbalanced energy metabolism leading to lipid storage. Only detailed understanding of the multiple molecular underpinnings of energy metabolism can provide the basis for future therapeutic options. Numerous aspects of obesity are currently studied, including the essential role of neural and endocrine control circuits, adaptive responses of catabolic and anabolic pathways, metabolic fuel sensors, regulation of appetite and satiation, sensory information processing, transcriptional control of metabolic processes, and the endocrine role of adipose tissue. These studies are predominantly fuelled by basic research on mammalian models or clinical studies, but these ?ndings were paralleled by important insights, which have emerged from studying invertebrate models.

The prevalence of obesity has dramatically increased in western and westernized societies, making the disease the second leading cause of unnecessary deaths in the US. Obesity results from imbalanced metabolic regulation leading to excessive lipid storage. As important novel entities in metabolic regulation, taste receptors and their cells are critical elements that adapt the gustatory system to metabolic signals and vice versa. The role of taste receptor genes in gastrointestinal tissues, as well as their dynamic regulation in gustatory and non-gustatory tissues in response to metabolic cues, has become the focus of an entirely new and rapidly developing research field with impacts on fuel sensing, metabolic control, and ingestive behavior. This book reflects the recent scientific progress in the field of fuel sensing in the mouth, GI tract, and brain and examines the olfactory bulb as a potential metabolic sensor and the brain-gut endocrine axis. It also touches on relevant novel molecular and cellular mechanisms regulating lipid storage and metabolism and covers the identification and functional characterization of obesity genes. Lastly, it illustrates the use of insect models to study relevant problems of energy homeostasis.