The generation of heat in order to maintain body temperature. The uncoupled oxidation of fatty acids contained within brown adipose tissue and SHIVERING are examples of thermogenesis in MAMMALS.

The processes of heating and cooling that an organism uses to control its temperature.

A thermogenic form of adipose tissue composed of BROWN ADIPOCYTES. It is found in newborns of many species including humans, and in hibernating mammals. Brown fat is richly vascularized, innervated, and densely packed with MITOCHONDRIA which can generate heat directly from the stored lipids.

An absence of warmth or heat or a temperature notably below an accustomed norm.

Involuntary contraction or twitching of the muscles. It is a physiologic method of heat production in man and other mammals.

The chemical reactions involved in the production and utilization of various forms of energy in cells.

Proteins encoded by the mitochondrial genome or proteins encoded by the nuclear genome that are imported to and resident in the MITOCHONDRIA.

The measure of the level of heat of a human or animal.

Heat production, or its measurement, of an organism at the lowest level of cell chemistry in an inactive, awake, fasting state. It may be determined directly by means of a calorimeter or indirectly by calculating the heat production from an analysis of the end products of oxidation within the organism or from the amount of oxygen utilized.

Fat cells with dark coloration due to the densely packed MITOCHONDRIA. They contain numerous small lipid droplets or vacuoles. Their stored lipids can be converted directly to energy as heat by the mitochondria.

Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.

Adaptation to a new environment or to a change in the old.

Calculation of the energy expenditure in the form of heat production of the whole body or individual organs based on respiratory gas exchange.

The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)

A plant family of the order Arales, subclass Arecidae, class Liliopsida (monocot). Many members contain OXALIC ACID and calcium oxalate (OXALATES).

A subclass of beta-adrenergic receptors (RECEPTORS, ADRENERGIC, BETA). The beta-3 adrenergic receptors are the predominant beta-adrenergic receptor type expressed in white and brown ADIPOCYTES and are involved in modulating ENERGY METABOLISM and THERMOGENESIS.

Lower than normal body temperature, especially in warm-blooded animals.

Fatty tissue composed of WHITE ADIPOCYTES and generally found directly under the skin (SUBCUTANEOUS FAT) and around the internal organs (ABDOMINAL FAT). It has less vascularization and less coloration than the BROWN FAT. White fat provides heat insulation, mechanical cushion, and source of energy.

Precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic.

The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.

A status with BODY WEIGHT that is grossly above the acceptable or desirable weight, usually due to accumulation of excess FATS in the body. The standards may vary with age, sex, genetic or cultural background. In the BODY MASS INDEX, a BMI greater than 30.0 kg/m2 is considered obese, and a BMI greater than 40.0 kg/m2 is considered morbidly obese (MORBID OBESITY).

Chemical agents that uncouple oxidation from phosphorylation in the metabolic cycle so that ATP synthesis does not occur. Included here are those IONOPHORES that disrupt electron transfer by short-circuiting the proton gradient across mitochondrial membranes.

The consumption of edible substances.

Specialized connective tissue composed of fat cells (ADIPOCYTES). It is the site of stored FATS, usually in the form of TRIGLYCERIDES. In mammals, there are two types of adipose tissue, the WHITE FAT and the BROWN FAT. Their relative distributions vary in different species with most adipose tissue being white.

A mobile, very volatile, highly flammable liquid used as an inhalation anesthetic and as a solvent for waxes, fats, oils, perfumes, alkaloids, and gums. It is mildly irritating to skin and mucous membranes.

Dioxoles are organic compounds containing a five-membered ring consisting of two oxygen atoms and two carbon atoms, often found as substructures in various natural and synthetic molecules, including certain pharmaceuticals and toxic dioxin pollutants.

Homogeneous liquid preparations that contain one or more chemical substances dissolved, i.e., molecularly dispersed, in a suitable solvent or mixture of mutually miscible solvents. For reasons of their ingredients, method of preparation, or use, they do not fall into another group of products.

Transport proteins that carry specific substances in the blood or across cell membranes.

The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.

Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)

Total number of calories taken in daily whether ingested or by parenteral routes.

Ingestion of a greater than optimal quantity of food.

A 16-kDa peptide hormone secreted from WHITE ADIPOCYTES. Leptin serves as a feedback signal from fat cells to the CENTRAL NERVOUS SYSTEM in regulation of food intake, energy balance, and fat storage.

A set of opposing, nonequilibrium reactions catalyzed by different enzymes which act simultaneously, with at least one of the reactions driven by ATP hydrolysis. The results of the cycle are that ATP energy is depleted, heat is produced and no net substrate-to-product conversion is achieved. Examples of substrate cycling are cycling of gluconeogenesis and glycolysis pathways and cycling of the triglycerides and fatty acid pathways. Rates of substrate cycling may be increased many-fold in association with hypermetabolic states resulting from severe burns, cold exposure, hyperthyroidism, or acute exercise.

The thoracolumbar division of the autonomic nervous system. Sympathetic preganglionic fibers originate in neurons of the intermediolateral column of the spinal cord and project to the paravertebral and prevertebral ganglia, which in turn project to target organs. The sympathetic nervous system mediates the body's response to stressful situations, i.e., the fight or flight reactions. It often acts reciprocally to the parasympathetic system.

A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.

Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.

A family of flowering plants in the order Piperales best known for the black pepper widely used in SPICES, and for KAVA and Betel used for neuroactive properties.

Natural hormones secreted by the THYROID GLAND, such as THYROXINE, and their synthetic analogs.

Cells in the body that store FATS, usually in the form of TRIGLYCERIDES. WHITE ADIPOCYTES are the predominant type and found mostly in the abdominal cavity and subcutaneous tissue. BROWN ADIPOCYTES are thermogenic cells that can be found in newborns of some species and hibernating mammals.

The metabolic process of breaking down LIPIDS to release FREE FATTY ACIDS, the major oxidative fuel for the body. Lipolysis may involve dietary lipids in the DIGESTIVE TRACT, circulating lipids in the BLOOD, and stored lipids in the ADIPOSE TISSUE or the LIVER. A number of enzymes are involved in such lipid hydrolysis, such as LIPASE and LIPOPROTEIN LIPASE from various tissues.

Region of hypothalamus between the ANTERIOR COMMISSURE and OPTIC CHIASM.

The relative amounts of various components in the body, such as percentage of body fat.

A 37-amino acid peptide derived from the C-terminal of GLICENTIN. It is mainly produced by the INTESTINAL L CELLS. Oxyntomodulin can reduce digestive secretions, delay gastric emptying, and reduced food intake.

FATTY ACIDS found in the plasma that are complexed with SERUM ALBUMIN for transport. These fatty acids are not in glycerol ester form.

A T3 thyroid hormone normally synthesized and secreted by the thyroid gland in much smaller quantities than thyroxine (T4). Most T3 is derived from peripheral monodeiodination of T4 at the 5' position of the outer ring of the iodothyronine nucleus. The hormone finally delivered and used by the tissues is mainly T3.

Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE.

Regular course of eating and drinking adopted by a person or animal.

The TEMPERATURE at the outer surface of the body.

The heat flow across a surface per unit area per unit time, divided by the negative of the rate of change of temperature with distance in a direction perpendicular to the surface. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

A constellation of responses that occur when an organism is exposed to excessive cold. In humans, a fall in skin temperature triggers gasping, hypertension, and hyperventilation.

One of two major pharmacologically defined classes of adrenergic receptors. The beta adrenergic receptors play an important role in regulating CARDIAC MUSCLE contraction, SMOOTH MUSCLE relaxation, and GLYCOGENOLYSIS.

Imaging the temperatures in a material, or in the body or an organ. Imaging is based on self-emanating infrared radiation (HEAT WAVES), or on changes in properties of the material or tissue that vary with temperature, such as ELASTICITY; MAGNETIC FIELD; or LUMINESCENCE.

A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.

A plant genus of the family NYMPHAEACEAE. The common name of lotus is also used for LOTUS and NELUMBO.

Simple amine found in the brain. It may be modulator of sympathetic functions. Its derivatives are adrenergic agonists and antagonists. It is also used in chemical industry.

Drugs that bind to and block the activation of ADRENERGIC BETA-3 RECEPTORS.

A nicotinic antagonist used primarily as a ganglionic blocker in animal research. It has been used as an antihypertensive agent but has been supplanted by more specific drugs in most clinical applications.

A general class of ortho-dihydroxyphenylalkylamines derived from tyrosine.

Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.

The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.

A hemeprotein that catalyzes the oxidation of the iodide radical to iodine with the subsequent iodination of many organic compounds, particularly proteins. EC 1.11.1.8.

Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.

Drugs that selectively bind to and activate beta-adrenergic receptors.

Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.

A nucleus of the middle hypothalamus, the largest cell group of the tuberal region with small-to-medium size cells.

The withholding of food in a structured experimental situation.

A guanine nucleotide containing two phosphate groups esterified to the sugar moiety.

Fats present in food, especially in animal products such as meat, meat products, butter, ghee. They are present in lower amounts in nuts, seeds, and avocados.

A flavoprotein oxidoreductase that has specificity for short-chain fatty acids. It forms a complex with ELECTRON-TRANSFERRING FLAVOPROTEINS and conveys reducing equivalents to UBIQUINONE.

The measurement of the quantity of heat involved in various processes, such as chemical reactions, changes of state, and formations of solutions, or in the determination of the heat capacities of substances. The fundamental unit of measurement is the joule or the calorie (4.184 joules). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)

A commonly used laboratory solvent. It was previously used as an anesthetic, but was banned from use in the U.S. due to its suspected carcinogenicity.

Collections of small neurons centrally scattered among many fibers from the level of the TROCHLEAR NUCLEUS in the midbrain to the hypoglossal area in the MEDULLA OBLONGATA.

Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)

Compounds that bind to and activate ADRENERGIC BETA-1 RECEPTORS.

The dormant state in which some warm-blooded animal species pass the winter. It is characterized by narcosis and by sharp reduction in body temperature and metabolic activity and by a depression of vital signs.

Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.

Solution that is usually 10 percent glucose but may be higher. An isotonic solution of glucose is 5 percent.

A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).

An order of small mammals comprising two families, Ochotonidae (pikas) and Leporidae (RABBITS and HARES). Head and body length ranges from about 125 mm to 750 mm. Hares and rabbits have a short tail, and the pikas lack a tail. Rabbits are born furless and with both eyes and ears closed. HARES are born fully haired with eyes and ears open. All are vegetarians. (From Nowak, Walker's Mammals of the World, 5th ed, p539-41)

Measuring instruments for determining the temperature of matter. Most thermometers used in the field of medicine are designed for measuring body temperature or for use in the clinical laboratory. (From UMDNS, 1999)

A syndrome that results from abnormally low secretion of THYROID HORMONES from the THYROID GLAND, leading to a decrease in BASAL METABOLIC RATE. In its most severe form, there is accumulation of MUCOPOLYSACCHARIDES in the SKIN and EDEMA, known as MYXEDEMA.

Full gratification of a need or desire followed by a state of relative insensitivity to that particular need or desire.

Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.

A genus of hamsters characterized by small size, very short tail, and short, broad feet with hairy soles.

Carbohydrates present in food comprising digestible sugars and starches and indigestible cellulose and other dietary fibers. The former are the major source of energy. The sugars are in beet and cane sugar, fruits, honey, sweet corn, corn syrup, milk and milk products, etc.; the starches are in cereal grains, legumes (FABACEAE), tubers, etc. (From Claudio & Lagua, Nutrition and Diet Therapy Dictionary, 3d ed, p32, p277)

The metabolic process of all living cells (animal and plant) in which oxygen is used to provide a source of energy for the cell.

The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.

Glucose in blood.

Agents that increase energy expenditure and weight loss by neural and chemical regulation. Beta-adrenergic agents and serotoninergic drugs have been experimentally used in patients with non-insulin dependent diabetes mellitus (NIDDM) to treat obesity.

A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.

Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.

A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.

An N-substituted amphetamine analog. It is a widely abused drug classified as a hallucinogen and causes marked, long-lasting changes in brain serotonergic systems. It is commonly referred to as MDMA or ecstasy.

A climate characterized by COLD TEMPERATURE for a majority of the time during the year.

Abstaining from all food.

Natural recurring desire for food. Alterations may be induced by APPETITE DEPRESSANTS or APPETITE STIMULANTS.

These metabolites of THYROXINE are formed by the deiodination of T3 or reverse T3.

The differentiation of pre-adipocytes into mature ADIPOCYTES.

The chemical reactions that occur within the cells, tissues, or an organism. These processes include both the biosynthesis (ANABOLISM) and the breakdown (CATABOLISM) of organic materials utilized by the living organism.

One of the FLAVORING AGENTS used to impart a meat-like flavor.

Regular insulin preparations that contain the SUS SCROFA insulin peptide sequence.

Also called the shoulder blade, it is a flat triangular bone, a pair of which form the back part of the shoulder girdle.

The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism.

Glycerolphosphate Dehydrogenase is an enzyme (EC 1.1.1.8) that catalyzes the reversible conversion of dihydroxyacetone phosphate to glycerol 3-phosphate, using nicotinamide adenine dinucleotide (NAD+) as an electron acceptor in the process.

Consumption of excessive DIETARY FATS.