Adipokines: Polypeptides produced by the ADIPOCYTES. They include LEPTIN; ADIPONECTIN; RESISTIN; and many cytokines of the immune system, such as TUMOR NECROSIS FACTOR-ALPHA; INTERLEUKIN-6; and COMPLEMENT FACTOR D (also known as ADIPSIN). They have potent autocrine, paracrine, and endocrine functions.Resistin: A 12-kDa cysteine-rich polypeptide hormone secreted by FAT CELLS in the ADIPOSE TISSUE. It is the founding member of the resistin-like molecule (RELM) hormone family. Resistin suppresses the ability of INSULIN to stimulate cellular GLUCOSE uptake.Adiponectin: A 30-kDa COMPLEMENT C1Q-related protein, the most abundant gene product secreted by FAT CELLS of the white ADIPOSE TISSUE. Adiponectin modulates several physiological processes, such as metabolism of GLUCOSE and FATTY ACIDS, and immune responses. Decreased plasma adiponectin levels are associated with INSULIN RESISTANCE; TYPE 2 DIABETES MELLITUS; OBESITY; and ATHEROSCLEROSIS.Nicotinamide Phosphoribosyltransferase: An enzyme that catalyzes the formation of nicotinamide mononucleotide (NMN) from nicotinamide and 5-phosphoribosyl-1-pyrophosphate, the rate-limiting step in the biosynthesis of the NAD coenzyme. It is also known as a growth factor for early B-LYMPHOCYTES, or an ADIPOKINE with insulin-mimetic effects (visfatin).Leptin: 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.Adipose Tissue: 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.Obesity: 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).Adipocytes: 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.Retinol-Binding Proteins, Plasma: Retinol binding proteins that circulate in the PLASMA. They are members of the lipocalin family of proteins and play a role in the transport of RETINOL from the LIVER to the peripheral tissues. The proteins are usually found in association with TRANSTHYRETIN.Insulin Resistance: Diminished effectiveness of INSULIN in lowering blood sugar levels: requiring the use of 200 units or more of insulin per day to prevent HYPERGLYCEMIA or KETOSIS.Adiposity: The amount of fat or lipid deposit at a site or an organ in the body, an indicator of body fat status.Metabolic Syndrome X: A cluster of metabolic risk factors for CARDIOVASCULAR DISEASES and TYPE 2 DIABETES MELLITUS. The major components of metabolic syndrome X include excess ABDOMINAL FAT; atherogenic DYSLIPIDEMIA; HYPERTENSION; HYPERGLYCEMIA; INSULIN RESISTANCE; a proinflammatory state; and a prothrombotic (THROMBOSIS) state. (from AHA/NHLBI/ADA Conference Proceedings, Circulation 2004; 109:551-556)Subcutaneous Fat: Fatty tissue under the SKIN through out the body.Adipose Tissue, White: 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.Receptors, Adipokine: Cell surface receptors for ADIPOKINES, cytokines secreted by the ADIPOCYTES.Receptors, Adiponectin: Cell surface receptors for ADIPONECTIN, an antidiabetic hormone secreted by ADIPOCYTES. Adiponectin receptors are membrane proteins with multiple cytoplasmic and extracellular regions. They are about 43 kDa and encoded by at least two genes with different affinities for globular and full-length adiponectin.Inflammation: A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.3T3-L1 Cells: A continuous cell line that is a substrain of SWISS 3T3 CELLS developed though clonal isolation. The mouse fibroblast cells undergo an adipose-like conversion as they move to a confluent and contact-inhibited state.Interleukin-6: A cytokine that stimulates the growth and differentiation of B-LYMPHOCYTES and is also a growth factor for HYBRIDOMAS and plasmacytomas. It is produced by many different cells including T-LYMPHOCYTES; MONOCYTES; and FIBROBLASTS.Body Mass Index: An indicator of body density as determined by the relationship of BODY WEIGHT to BODY HEIGHT. BMI=weight (kg)/height squared (m2). BMI correlates with body fat (ADIPOSE TISSUE). Their relationship varies with age and gender. For adults, BMI falls into these categories: below 18.5 (underweight); 18.5-24.9 (normal); 25.0-29.9 (overweight); 30.0 and above (obese). (National Center for Health Statistics, Centers for Disease Control and Prevention)Intra-Abdominal Fat: Fatty tissue inside the ABDOMINAL CAVITY, including visceral fat and retroperitoneal fat. It is the most metabolically active fat in the body and easily accessible for LIPOLYSIS. Increased visceral fat is associated with metabolic complications of OBESITY.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Inflammation Mediators: The endogenous compounds that mediate inflammation (AUTACOIDS) and related exogenous compounds including the synthetic prostaglandins (PROSTAGLANDINS, SYNTHETIC).Overnutrition: An imbalanced NUTRITIONAL STATUS resulting from excessive intake of nutrients. Generally, overnutrition generates an energy imbalance between food consumption and energy expenditure leading to disorders such as OBESITY.C-Reactive Protein: A plasma protein that circulates in increased amounts during inflammation and after tissue damage.Tumor Necrosis Factor-alpha: Serum glycoprotein produced by activated MACROPHAGES and other mammalian MONONUCLEAR LEUKOCYTES. It has necrotizing activity against tumor cell lines and increases ability to reject tumor transplants. Also known as TNF-alpha, it is only 30% homologous to TNF-beta (LYMPHOTOXIN), but they share TNF RECEPTORS.Receptors, Leptin: Cell surface receptors for obesity factor (LEPTIN), a hormone secreted by the WHITE ADIPOCYTES. Upon leptin-receptor interaction, the signal is mediated through the JAK2/STAT3 pathway to regulate food intake, energy balance and fat storage.Cytokines: Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.Hormones, Ectopic: Hormones released from neoplasms or from other cells that are not the usual sources of hormones.Insulin: 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).Omentum: A double-layered fold of peritoneum that attaches the STOMACH to other organs in the ABDOMINAL CAVITY.Intercellular Signaling Peptides and Proteins: Regulatory proteins and peptides that are signaling molecules involved in the process of PARACRINE COMMUNICATION. They are generally considered factors that are expressed by one cell and are responded to by receptors on another nearby cell. They are distinguished from HORMONES in that their actions are local rather than distal.Ghrelin: A 28-amino acid, acylated, orexigenic peptide that is a ligand for GROWTH HORMONE SECRETAGOGUE RECEPTORS. Ghrelin is widely expressed but primarily in the stomach in the adults. Ghrelin acts centrally to stimulate growth hormone secretion and food intake, and peripherally to regulate energy homeostasis. Its large precursor protein, known as appetite-regulating hormone or motilin-related peptide, contains ghrelin and obestatin.Peptide Hormones: Hormones synthesized from amino acids. They are distinguished from INTERCELLULAR SIGNALING PEPTIDES AND PROTEINS in that their actions are systemic.Angiopoietins: A family of structurally-related angiogenic proteins of approximately 70 kDa in size. They have high specificity for members of the TIE RECEPTOR FAMILY.Lipocalins: A diverse family of extracellular proteins that bind to small hydrophobic molecules. They were originally characterized as transport proteins, however they may have additional roles such as taking part in the formation of macromolecular complexes with other proteins and binding to CELL SURFACE RECEPTORS.Blood Glucose: Glucose in blood.Plasminogen Activator Inhibitor 1: A member of the serpin family of proteins. It inhibits both the tissue-type and urokinase-type plasminogen activators.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Body Weight: The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.