Adipokine
Encyclopedia
The adipokines or adipocytokines (Greek adipo-, fat; cyto-, cell; and -kinos, movement) are cytokine
s (cell
-to-cell signaling protein
s) secreted by adipose tissue
.
Members include:
As of 2008, the current terminology refers to a cytokine
as an immunomodulating agent. However, conflicting data exists about what is termed a cytokine and what is termed a hormone and more research is needed in this area of defining cytokines and hormones. Under the current terminology, adiponectin
, leptin
(Ob ligand), and resistin
are not appropriately considered adipokines (cytokines) as they do not act on the immune system. (Harrison's Principles of Internal Medicine). Often, these peptides (adiponectin
, leptin
, and resistin
) are referred to as adipokines, however they can be more accurately put into the larger, growing list of adipose derived hormones
.
Cytokine
Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...
s (cell
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
-to-cell signaling protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s) secreted by adipose tissue
Adipose tissue
In histology, adipose tissue or body fat or fat depot or just fat is loose connective tissue composed of adipocytes. It is technically composed of roughly only 80% fat; fat in its solitary state exists in the liver and muscles. Adipose tissue is derived from lipoblasts...
.
Members include:
- chemerinChemerinChemerin, also known as retinoic acid receptor responder protein 2 , tazarotene-induced gene 2 protein , or RAR-responsive protein TIG2 is a protein that in humans is encoded by the RARRES2 gene.- Function :...
- interleukin-6 (IL-6)
- plasminogen activator inhibitor-1Plasminogen activator inhibitor-1Plasminogen activator inhibitor-1 also known as endothelial plasminogen activator inhibitor or serpin E1 is a protein that in humans is encoded by the SERPINE1 gene....
(PAI-1) - retinol binding protein 4Retinol binding proteinRetinol-binding proteins are a family of proteins with diverse functions. They are carrier proteins that bind retinol.Assessment of retinol-binding protein is used to determine visceral protein mass in nutritional studies related to health.-Genes:...
(RBP4) - tumor necrosis factor-alpha (TNFα)
- visfatin
- LeptinLeptinLeptin is a 16 kDa protein hormone that plays a key role in regulating energy intake and energy expenditure, including appetite and metabolism. It is one of the most important adipose derived hormones...
- AdiponectinAdiponectinAdiponectin is a protein which in humans is encoded by the ADIPOQ gene.- Structure :...
- ApelinApelinApelin is a peptide that in humans is encoded by the APLN gene. Apelin is the endogenous ligand for the G-protein-coupled APJ receptor that is expressed at the surface of some cell types...
As of 2008, the current terminology refers to a cytokine
Cytokine
Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...
as an immunomodulating agent. However, conflicting data exists about what is termed a cytokine and what is termed a hormone and more research is needed in this area of defining cytokines and hormones. Under the current terminology, adiponectin
Adiponectin
Adiponectin is a protein which in humans is encoded by the ADIPOQ gene.- Structure :...
, leptin
Leptin
Leptin is a 16 kDa protein hormone that plays a key role in regulating energy intake and energy expenditure, including appetite and metabolism. It is one of the most important adipose derived hormones...
(Ob ligand), and resistin
Resistin
Resistin also known as adipose tissue-specific secretory factor or C/EBP-epsilon-regulated myeloid-specific secreted cysteine-rich protein is a cysteine-rich protein that in humans is encoded by the RETN gene....
are not appropriately considered adipokines (cytokines) as they do not act on the immune system. (Harrison's Principles of Internal Medicine). Often, these peptides (adiponectin
Adiponectin
Adiponectin is a protein which in humans is encoded by the ADIPOQ gene.- Structure :...
, leptin
Leptin
Leptin is a 16 kDa protein hormone that plays a key role in regulating energy intake and energy expenditure, including appetite and metabolism. It is one of the most important adipose derived hormones...
, and resistin
Resistin
Resistin also known as adipose tissue-specific secretory factor or C/EBP-epsilon-regulated myeloid-specific secreted cysteine-rich protein is a cysteine-rich protein that in humans is encoded by the RETN gene....
) are referred to as adipokines, however they can be more accurately put into the larger, growing list of adipose derived hormones
Adipose derived hormones
Adipose tissue is an important endocrine organ that secretes numerous protein hormones, including leptin, adiponectin, and resistin. These hormones generally influence energy metabolism, which is of great interest to the understanding and treatment of type 2 diabetes and obesity.Their relative...
.