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Somatomedin
Somatomedins are a group of proteins produced predominantly by the liver when growth hormones act on target tissue. Somatomedins inhibit the release of growth hormones by acting directly on anterior pituitary and by stimulating the secretion of somatostatin from the hypothalamus. Somatomedins are a group of proteins that promote cell growth and division in response to stimulation by growth hormone (GH), also known as somatotropin (STH). Somatomedins have similar biological effects to somatotropin. In addition to their actions that stimulate growth, somatomedins also stimulate production of somatostatin, which suppresses growth hormone release. Thus, levels of somatomedins are controlled via negative feedback through the intermediates of somatostatin and growth hormone. Somatomedins are produced in many tissues and have autocrine and paracrine actions in addition to their endocrine action. The liver is thought to be the predominant source of circulating somatomedins. Three forms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitronectin
Vitronectin (VTN or VN) is a glycoprotein of the hemopexin family which is synthesized and excreted by the liver, and abundantly found in serum, the extracellular matrix and bone. In humans it is encoded by the ''VTN'' gene. Vitronectin binds to integrin alpha-V beta-3 and thus promotes cell adhesion and spreading. It also inhibits the membrane-damaging effect of the terminal cytolytic complement pathway and binds to several serpins (serine protease inhibitors). It is a secreted protein and exists in either a single chain form or a clipped, two chain form held together by a disulfide bond. Vitronectin has been speculated to be involved in hemostasis and tumor malignancy. Structure Vitronectin is a 75 kDa glycoprotein, consisting of 478 amino acid residues. About one-third of the protein's molecular mass is composed of carbohydrates. On occasion, the protein is cleaved after arginine 379, to produce two-chain vitronectin, where the two parts are linked by a disulfid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatomedin B
Somatomedin B is a Serum (blood), serum factor of unknown function, is a small cysteine-rich peptide, derived Proteolysis, proteolytically from the N-terminus of the cell adhesion, cell-substrate adhesion protein vitronectin. Cys-rich somatomedin B-like domains are found in a number of proteins, including plasma-cell membrane glycoprotein (which has nucleotide pyrophosphate and alkaline phosphodiesterase I activities) and placental protein 11 (which appears to possess amidolytic activity). The SMB domain of vitronectin has been demonstrated to interact with both the urokinase receptor and the plasminogen activator inhibitor-1 (PAI-1) and the conserved cysteines of the NPP1 somatomedin B-like domain have been shown to mediate Protein dimer, homodimerization. As shown in the following schematic representation below the SMB domain contains eight Cys residues, arranged into four disulfide bonds. It has been suggested that the active SMB domain may be permitted considerable disulfide bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatostatin
Somatostatin, also known as growth hormone-inhibiting hormone (GHIH) or by #Nomenclature, several other names, is a peptide hormone that regulates the endocrine system and affects neurotransmission and cell proliferation via interaction with G protein-coupled somatostatin receptors and inhibition of the release of numerous secondary hormones. Somatostatin inhibits insulin and glucagon secretion. Somatostatin has two active forms produced by the alternative cleavage of a single preproprotein: one consisting of 14 amino acids (shown in infobox to right), the other consisting of 28 amino acids. Among the vertebrates, there exist six different somatostatin genes that have been named: ''SS1'', ''SS2'', ''SS3'', ''SS4'', ''SS5'' and ''SS6''. Zebrafish have all six. The six different genes, along with the five different somatostatin receptors, allow somatostatin to possess a large range of functions. Humans have only one somatostatin gene, ''SST''. Nomenclature Synonyms of "somatost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Growth Hormone
Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in human development. GH also stimulates production of insulin-like growth factor 1 (IGF-1) and increases the concentration of glucose and free fatty acids. It is a type of mitogen which is specific only to the receptors on certain types of cells. GH is a 191-amino acid, single-chain polypeptide that is synthesized, stored and secreted by somatotropic cells within the lateral wings of the anterior pituitary gland. A recombinant form of HGH called somatropin ( INN) is used as a prescription drug to treat children's growth disorders and adult growth hormone deficiency. In the United States, it is only available legally from pharmacies by prescription from a licensed health care provider. In recent years in the United States, some health ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatotropin
Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in human development. GH also stimulates production of insulin-like growth factor 1 (IGF-1) and increases the concentration of glucose and free fatty acids. It is a type of mitogen which is specific only to the receptors on certain types of cells. GH is a 191-amino acid, single-chain polypeptide that is synthesized, stored and secreted by somatotropic cells within the lateral wings of the anterior pituitary gland. A recombinant form of HGH called somatropin (INN) is used as a prescription drug to treat children's growth disorders and adult growth hormone deficiency. In the United States, it is only available legally from pharmacies by prescription from a licensed health care provider. In recent years in the United States, some health care pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EMedicine
eMedicine is an online clinical medical knowledge base founded in 1996 by doctors Scott Plantz and Jonathan Adler, and computer engineers Joanne Berezin and Jeffrey Berezin. The eMedicine website consists of approximately 6,800 medical topic review articles, each of which is associated with a clinical subspecialty "textbook". The knowledge base includes over 25,000 clinically multimedia files. Each article is authored by board certified specialists in the subspecialty to which the article belongs and undergoes three levels of physician peer-review, plus review by a Doctor of Pharmacy. The article's authors are identified with their current faculty appointments. Each article is updated yearly, or more frequently as changes in practice occur, and the date is published on the article. eMedicine.com was sold to WebMD in January, 2006 and is available as the Medscape Reference. History Plantz, Adler and Berezin evolved the concept for eMedicine.com in 1996 and deployed the initia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autocrine
Autocrine signaling is a form of cell signaling in which a cell secretes a hormone or chemical messenger (called the autocrine agent) that binds to autocrine receptors on that same cell, leading to changes in the cell. This can be contrasted with paracrine signaling, intracrine signaling, or classical endocrine signaling. Examples An example of an autocrine agent is the cytokine interleukin-1 in monocytes. When interleukin-1 is produced in response to external stimuli, it can bind to cell-surface receptors on the same cell that produced it. Another example occurs in activated T cell lymphocytes, i.e., when a T cell is induced to mature by binding to a peptide: MHC complex on a professional antigen-presenting cell and by the B7: CD28 costimulatory signal. Upon activation, "low-affinity" IL-2 receptors are replaced by "high-affinity" IL-2 receptors consisting of α, β, and γ chains. The cell then releases IL-2, which binds to its own new IL-2 receptors, causing self-stimul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paracrine
In cellular biology, paracrine signaling is a form of cell signaling, a type of cellular communication (biology), cellular communication in which a Cell (biology), cell produces a signal to induce changes in nearby cells, altering the behaviour of those cells. Signaling molecules known as paracrine factors diffuse over a relatively short distance (local action), as opposed to cell signaling by endocrine system, endocrine factors, hormones which travel considerably longer distances via the circulatory system; juxtacrine signaling, juxtacrine interactions; and autocrine signaling. Cells that produce paracrine factors secrete them into the immediate extracellular environment. Factors then travel to nearby cells in which the gradient of factor received determines the outcome. However, the exact distance that paracrine factors can travel is not certain. Although paracrine signaling elicits a diverse array of responses in the induced cells, most paracrine factors utilize a relatively s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endocrine
The endocrine system is a messenger system in an organism comprising feedback loops of hormones that are released by internal glands directly into the circulatory system and that target and regulate distant organs. In vertebrates, the hypothalamus is the neural control center for all endocrine systems. In humans, the major endocrine glands are the thyroid, parathyroid, pituitary, pineal, and adrenal glands, and the (male) testis and (female) ovaries. The hypothalamus, pancreas, and thymus also function as endocrine glands, among other functions. (The hypothalamus and pituitary glands are organs of the neuroendocrine system. One of the most important functions of the hypothalamusit is located in the brain adjacent to the pituitary glandis to link the endocrine system to the nervous system via the pituitary gland.) Other organs, such as the kidneys, also have roles within the endocrine system by secreting certain hormones. The study of the endocrine system and its disorde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatomedin A
Insulin-like growth factor 2 (IGF-2) is one of three protein hormones that share structural similarity to insulin. The MeSH definition reads: "A well-characterized neutral peptide believed to be secreted by the liver and to circulate in the blood. It has growth-regulating, insulin-like and mitogenic activities. The growth factor has a major, but not absolute, dependence on somatotropin. It is believed to be a major fetal growth factor in contrast to insulin-like growth factor 1 (IGF-1), which is a major growth factor in adults." Gene structure In humans, the gene is located on chromosome 11p15.5, a region which contains numerous imprinted genes. In mice this homologous region is found at distal chromosome 7. In both organisms, ''IGF2'' is imprinted, with expression resulting favourably from the paternally inherited allele. However, in some human brain regions a loss of imprinting occurs resulting in both ''IGF2'' and being transcribed from both parental alleles. The prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
