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Leptin
Leptin (from Ancient Greek, Greek λεπτός ''leptos'', "thin" or "light" or "small"), also known as obese protein, is a protein hormone predominantly made by adipocytes (cells of adipose tissue). Its primary role is likely to regulate long-term Energy homeostasis, energy balance. As one of the major signals of energy status, leptin levels influence appetite, Hunger (physiology), satiety, and motivated behaviors oriented toward the maintenance of energy reserves (e.g., feeding, foraging behaviors). The amount of circulating leptin correlates with the amount of energy reserves, mainly Triglyceride, triglycerides stored in adipose tissue. High leptin levels are interpreted by the brain that energy reserves are high, whereas low leptin levels indicate that energy reserves are low, in the process adapting the organism to Starvation response, starvation through a variety of metabolic, endocrine, neurobiochemical, and behavioral changes. Leptin is coded for by the ''LEP'' gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Leptin Receptor
Leptin receptor, also known as LEP-R or OB-R, is a type I cytokine receptor, a protein that in humans is encoded by the ''LEPR'' gene. LEP-R functions as a receptor for the fat cell-specific hormone leptin. LEP-R has also been designated as CD295 (cluster of differentiation 295). Its location is the cell membrane, and it has extracellular, trans-membrane and intracellular sections (''protein regions''). History The Leptin Receptor was discovered in 1995 by Louis Tartaglia and his colleagues at Millennium Pharmaceuticals. This same team demonstrated the leptin receptor was expressed by the mouse db gene. Furthermore, in 1996, after co-discovering the Leptin gene with Jeffrey Friedman et al. in 1994, (which involved a reverse genetic/positional cloning strategy to clone ''ob'' and ''db)'', Rudolph Leibel, working with collaborators also at Millennium Pharmaceuticals and colleague Streamson Chua, confirmed cloning of the leptin receptor by demonstrating that an apparent leptin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Adipose Tissue
Adipose tissue (also known as body fat or simply fat) is a loose connective tissue composed mostly of adipocytes. It also contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, Blood vessel, vascular endothelial cells and a variety of White blood cell, immune cells such as adipose tissue macrophages. Its main role is to store energy in the form of lipids, although it also cushions and Thermal insulation, insulates the body. Previously treated as being hormonally inert, in recent years adipose tissue has been recognized as a major endocrine organ, as it produces hormones such as leptin, estrogen, resistin, and cytokines (especially TNF-alpha, TNFα). In obesity, adipose tissue is implicated in the chronic release of pro-inflammatory markers known as adipokines, which are responsible for the development of metabolic syndromea constellation of diseases including type 2 diabetes, cardiovascular disease and atherosclerosis. Adipose tissue is d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hunger (physiology)
Hunger is a sensation that motivates the consumption of food. The sensation of hunger typically manifests after only a few hours without eating and is generally considered to be unpleasant. Satiety occurs between 5 and 20 minutes after eating. There are several theories about how the feeling of hunger arises. The desire to eat food, or appetite, is another sensation experienced with regard to eating. The term ''hunger'' is also the most commonly used in social science and policy discussions to describe the condition of people who suffer from a chronic lack of sufficient food and constantly or frequently experience the sensation of hunger, and can lead to malnutrition. A healthy, well-nourished individual can survive for weeks without food intake (see fasting), with claims ranging from three to ten weeks. Satiety is the opposite of hunger; it is the sensation of feeling full. Hunger pangs The physical sensation of hunger is related to the contractions of the muscles of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Appetite
Appetite is the desire to eat food items, usually due to hunger. Appealing foods can stimulate appetite even when hunger is absent, although appetite can be greatly reduced by satiety. Appetite exists in all higher life-forms, and serves to regulate adequate energy intake to maintain metabolic needs. It is regulated by a close interplay between the digestive tract, adipose tissue and the brain. Appetite has a relationship with every individual's behavior. Appetitive behaviour also known as approach behaviour, and consummatory behaviour, are the only processes that involve energy intake, whereas all other behaviours affect the release of energy. When stressed, appetite levels may increase and result in an increase of food intake. Decreased desire to eat is termed anorexia, while polyphagia (or "hyperphagia") is increased eating. Dysregulation of appetite contributes to ARFID, anorexia nervosa, bulimia nervosa, cachexia, overeating, and binge eating disorder. Role in disease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Eating
Eating (also known as consuming) is the ingestion of food. In biology, this is typically done to provide a heterotrophic organism with energy and nutrients and to allow for growth. Animals and other heterotrophs must eat in order to survive – carnivores eat other animals, herbivores eat plants, omnivores consume a mixture of both plant and animal matter, and detritivores eat detritus. Fungi digest organic matter outside their bodies as opposed to animals that digest their food inside their bodies. For humans, eating is more complex, but is typically an activity of daily living. Physicians and dieticians consider a healthful diet essential for maintaining peak physical condition. Some individuals may limit their amount of nutritional intake. This may be a result of a lifestyle choice: as part of a diet or as religious fasting. Limited consumption may be due to hunger or famine. Overconsumption of calories may lead to obesity and the reasons behind it are myriad, however, it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Satiety
Satiety ( /səˈtaɪ.ə.ti/ ''sə-TYE-ə-tee'') is a state or condition of fullness gratified beyond the point of satisfaction, the opposite of hunger. Following satiation (meal termination), satiety is a feeling of fullness lasting until the next meal. When food is present in the GI tract after a meal, satiety signals overrule hunger signals, but satiety slowly fades as hunger increases. The satiety center in animals is located in ventromedial nucleus of the hypothalamus. Mechanism Satiety is signaled through the vagus nerve as well as circulating hormones. During intake of a meal, the stomach must stretch to accommodate this increased volume. This gastric accommodation activates stretch receptors in the proximal (upper) portion of the stomach. These receptors then signal through afferent vagus nerve fibers to the hypothalamus, increasing satiety. Signalling factors In addition, as the food moves into the duodenum, duodenal cells release multiple substances that affect di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Obesity
Obesity is a medical condition, considered by multiple organizations to be a disease, in which excess Adipose tissue, body fat has accumulated to such an extent that it can potentially have negative effects on health. People are classified as obese when their body mass index (BMI)—a person's weight divided by the square of the person's height—is over ; the range is defined as overweight. Some East Asian countries use lower values to calculate obesity. Obesity is a major cause of disability and is Obesity-associated morbidity, correlated with various diseases and conditions, particularly cardiovascular diseases, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis. Obesity has individual, socioeconomic, and environmental causes. Some known causes are Western pattern diet, diet, low physical activity, automation, urbanization, quantitative trait locus, genetic susceptibility, medications, mental disorders, Economic policy, economic pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Adipose Cells
Adipocytes, also known as lipocytes and fat cells, are the cells that primarily compose adipose tissue, specialized in storing energy as fat. Adipocytes are derived from mesenchymal stem cells which give rise to adipocytes through adipogenesis. In cell culture, adipocyte progenitors can also form osteoblasts, myocytes and other cell types. There are two types of adipose tissue, white adipose tissue (WAT) and brown adipose tissue (BAT), which are also known as white and brown fat, respectively, and comprise two types of fat cells. Structure White fat cells White fat cells contain a single large lipid droplet surrounded by a layer of cytoplasm, and are known as unilocular. The nucleus is flattened and pushed to the periphery. A typical fat cell is 0.1 mm in diameter with some being twice that size, and others half that size. However, these numerical estimates of fat cell size depend largely on the measurement method and the location of the adipose tissue. The fat stored is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hypothalamus
The hypothalamus (: hypothalami; ) is a small part of the vertebrate brain that contains a number of nucleus (neuroanatomy), nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamus is located below the thalamus and is part of the limbic system. It forms the Basal (anatomy), basal part of the diencephalon. All vertebrate brains contain a hypothalamus. In humans, it is about the size of an Almond#Nut, almond. The hypothalamus has the function of regulating certain metabolic biological process, processes and other activities of the autonomic nervous system. It biosynthesis, synthesizes and secretes certain neurohormones, called releasing hormones or hypothalamic hormones, and these in turn stimulate or inhibit the secretion of hormones from the pituitary gland. The hypothalamus controls thermoregulation, body temperature, hunger (physiology), hunger, important aspects o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Insulin Resistance
Insulin resistance (IR) is a pathological response in which cells in insulin-sensitive tissues in the body fail to respond normally to the hormone insulin or downregulate insulin receptors in response to hyperinsulinemia. Insulin is a hormone that facilitates the transport of glucose from blood into cells, thereby reducing blood glucose (blood sugar). Insulin is released by the pancreas in response to carbohydrates consumed in the diet. In states of insulin resistance, the same amount of insulin does not have the same effect on glucose transport and blood sugar levels. There are many causes of insulin resistance and the underlying process is still not completely understood. Risk factors for insulin resistance include obesity, sedentary lifestyle, family history of diabetes, various health conditions, and certain medications. Insulin resistance is considered a component of the metabolic syndrome. Insulin resistance can be improved or reversed with lifestyle approaches, such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Adipocyte
Adipocytes, also known as lipocytes and fat cells, are the cell (biology), cells that primarily compose adipose tissue, specialized in storing energy as fat. Adipocytes are derived from mesenchymal stem cells which give rise to adipocytes through adipogenesis. In cell culture, adipocyte progenitors can also form osteoblasts, myocytes and other cell types. There are two types of adipose tissue, white adipose tissue (WAT) and brown adipose tissue (BAT), which are also known as white and brown fat, respectively, and comprise two types of fat cells. Structure White fat cells White fat cells contain a single large lipid droplet surrounded by a layer of cytoplasm, and are known as unilocular. The Cell nucleus, nucleus is flattened and pushed to the periphery. A typical fat cell is 0.1 mm in diameter with some being twice that size, and others half that size. However, these numerical estimates of fat cell size depend largely on the measurement method and the location of the adi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Energy Homeostasis
In biology, energy homeostasis, or the homeostatic control of energy balance, is a biological process that involves the coordinated homeostatic regulation of food intake (energy inflow) and energy expenditure (energy outflow). The human brain, particularly the hypothalamus, plays a central role in regulating energy homeostasis and generating the sense of hunger by integrating a number of biochemical signals that transmit information about energy balance. Fifty percent of the energy from glucose metabolism is immediately converted to heat. Energy homeostasis is an important aspect of bioenergetics. Definition In the US, biological energy is expressed using the energy unit Calorie with a capital C (i.e. a kilocalorie), which equals the energy needed to increase the temperature of 1 kilogram of water by 1 °C (about 4.18 k J). Energy balance, through biosynthetic reactions, can be measured with the following equation: :''Energy intake (from food and fluids) = Ene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
