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Glucagon is an important hormone involved in carbohydrate metabolism. The hormone is synthesized and secreted from alpha cells (a-cells) of the islets of Langerhans, which are located in the endocrine portion of the pancreas. Glucagon is released when the glucose level in the blood is low (hypoglycemia), causing the liver to convert stored glycogen into glucose and release it into the bloodstream. The action of glucagon is thus opposite to that of insulin, which instructs the body's cells to take in glucose from the blood in times of satiation.
Glucagon is beneficial for the culture of some cell types. It has been used in some biochemical regulation studies of glycogenolysis in hepatocytes. It has been also been found to induce DNA replication in primary cultures of adult rat hepatocytes when used in combinations with EGF and Insulin. Glucagon increases the blood glucose concentration by promoting rapid breakdown of liver glycogen, and also acts to relax smooth muscle such as the gastrointestinal tract.

Glia Maturation Factor-Beta (GMF-Beta) is a 17 kDa protein nerve gorwth factor identified as a growth and differentiation factor in the vertebrate brain.
Glia Maturation Factor-Beta stimulates differentiation of normal neurons as well as glial cells. GMFB inhibits the proliferation of the N-18 neuroblastoma line and the C6 glioma line while promoting their phenotypic expression.
GMF-beta inhances the phenotypic expression of glia & neurons thus inhibits the proliferation of their respective tumors when added to cell culture. Although astrocytes produce GMF-b and stores it inside the cells, they don’t secrete the GMF-B into the cultured medium. Cell- surface GMFb acts on the target cells at close range when cells are in direct contact. GMF-Beta is produced by thymic epithelial cells and plays an important role in T cell development in favor of CD4+ T cells.
GMF-Beta is a brain-specific protein which belongs to the actin-binding proteins (ADF) family. GMF-beta appears to play a role in the differentiation, maintenance, and regeneration of the nervous system. It also supports the progression of certain auto-immune diseases, possibly through its ability to induce the production and secretion of various pro-inflammatory cytokines.

Human thyrostimulin ranks among the glycoprotein hormone family. These hormones consist of two subunits, the common alpha- and specific beta-subunits, which associate noncovalently to form a heterodimer. The alpha-subunit combines with four distinct beta-subunits giving rise to four biologically active hormones in human: FSH, LH, TSH, and CG. FSH, LH, and TSH, mainly expressed in the anterior pituitary, are essential for coordinated endocrine regulation in the hypothalamus- pituitary axis and show to activate specific G protein–coupled receptors in the thyroid (TSH receptor) and gonads (LH and FSH receptors), respectively.
The heterodimeric glycoprotein hormones have only been identified in vertebrates and are highly conserved in organisms from primitive rayfin fish (Chondrostei) to human in both primary sequences and functional characteristics.
Corticotroph-derived glycoprotein hormone (CGH), also referred to as thyrostimulin, is a noncovalent heterodimer of glycoprotein hormone alpha 2 (GPHA2) and glycoprotein hormone beta 5 (GPHB5).
Recombinant A2/B5 heterodimeric glycoproteins activates human TSH receptors, but not LH and FSH receptors, and shows high affinity to TSH receptors in a radioligand receptor assay. The heterodimer also stimulates cAMP production and thymidine incorporation by cultured thyroid cells and increases serum thyroxine levels in TSH-suppressed rats in vivo. This new heterodimeric glycoprotein hormone was named as thyrostimulin based on its thyroid-stimulating activity. The expression of thyrostimulin in the anterior pituitary known to express TSH receptors suggested a paracrine mechanism.

CD68 encodes a 110-kD transmembrane glycoprotein that is highly expressed by human monocytes and tissue macrophages. It is a member of the lysosomal/endosomal-associated membrane glycoprotein (LAMP) family. The protein primarily localizes to lysosomes and endosomes with a smaller fraction circulating to the cell surface. It is a type I integral membrane protein with a heavily glycosylated extracellular domain and binds to tissue- and organ-specific lectins or selectins. The protein is also a member of the scavenger receptor family. Scavenger receptors typically function to clear cellular debris, promote phagocytosis, and mediate the recruitment and activation of macrophages. Alternative splicing results in multiple transcripts encoding different isoforms.

The protein encoded by this gene is a member of the bone morphogenetic protein family which is part of the transforming growth factor-beta superfamily. The superfamily includes large families of growth and differentiation factors. Bone morphogenetic proteins were originally identified by an ability of demineralized bone extract to induce endochondral osteogenesis in vivo in an extraskeletal site. This particular family member plays an important role in the onset of endochondral bone formation in humans, and a reduction in expression has been associated with a variety of bone diseases, including the heritable disorder Fibrodysplasia Ossificans Progressiva. Alternative splicing in the 5' untranslated region of this gene has been described and three variants are described, all encoding an identical protein.

Adiponectin is a hormone exclusively expressed from adipose tissue. Many studies demonstrate that adiponectin has direct anti-diabetic, anti-atherogenic and anti-inflammatory functions. APM-1 can increase insulin sensitivity of skeletal muscle, attenuate hepatic lipogenesis and luconeogenesis, regulate NO production in endothelial cells, inhibit proliferation of smooth muscle cells and prevent lipid accumulation of macrophage cells.
In the circulation, adiponectin is present as three different oligomeric complexes, including the high molecular weight (HMW), the middle molecular weight (MMW, also called hexamer) and low molecular weigh (MMW, also called trimer) forms 8. Different oligomeric complex of adiponectin activates different signaling pathways and exerts distinct functions.

Thiosulfate sulfurtransferase (glpE) is a mitochondrial matrix enzyme which is encoded by the nucleus. Escherichia coli glpE is a prototype for the single-domain rhodanese superfamily. glpE catalyzes the sulfur-transfer reaction in which a sulfur atom is transferred from thiosulfate to cyanide by a double-displacement mechanism.

Glycoprotein Nmb (GPNMB) is a member of the PMEL/NMB family. GPNMB is a type I transmembrane glycoprotein which exhibits homology to the pMEL17 precursor, a melanocyte-specific protein. GPNMB is expressed in the lowly metastatic human melanoma cell lines and xenografts but has no expression in the highly metastatic cell lines. GPNMB might be involved in growth delay and reduction of metastatic potential. GPNMB is up-regulated in a number of cancer cells, including in glioblastoma multiforme. GPNMB is expressed in many melanoma cells, as well as in tissue macrophages, including liver Kuppfer cells and lung alveolar macrophages, in podocytes and in some cells of the ciliary body of the eye (at protein level). GPNMB is hardly detectable in the healthy brain.

LYVE-1 has been identified as a major receptor for HA (extracellular matrix glycosaminoglycan hyaluronan) on the lymph vessel wall. The deduced amino acid sequence of LYVE-1 predicts a 322-residue type I integral membrane polypeptide 41% similar to the CD44 HA receptor with a 212-residue extracellular domain containing a single Link module the prototypic HA binding domain of the Link protein superfamily. Like CD44, the LYVE-1 molecule binds both soluble and immobilized HA. However, unlike CD44, the LYVE-1 molecule colocalizes with HA on the luminal face of the lymph vessel wall and is completely absent from blood vessels. Hence, LYVE-1 is the first lymph-specific HA receptor to be characterized and is a uniquely powerful marker for lymph vessels themselves.

Leptin is a protein hormone. It is mainly produced in adipose cells that regulate energy homeostasis by restraining hunger. Leptin ties to nuclear receptors in the hypothalamus (arcuate nucleus). Similar to insulin resistance in type II diabetes, in obesity there is a decrease in the sensitivity towards leptin, ending in a failure to identify satiety, even in high levels of energy stores or leptin itself. Full-length cDNA encoding 2 leptin sequences (tLepA and tLepB) and 1 leptin receptor sequence (tLepR) exists in tilapia (Oreochromis niloticus). The full-length cDNA of tLepR is 3423 bp, encoding a protein of 1140 amino acid which contained all functionally important domains conserved among vertebrate leptin receptors. The cDNAs of tLepA and tLepB are 486 bp and 459 bp in length, encoding proteins of 161 aa and 152 aa, respectively. The three-dimensional structures of tLepA and tLepB demonstrates strong conservation of tertiary structure with that of human leptin comprised of 4 helixes.

FAD-linked sulfhydryl oxidase ALR (GFER) is a member of the Erv1/ALR family of proteins, which is found in higher and lower eukaryotes. GFER is a hepatotrophic growth factor and flavin-linked sulfhydryl oxidase expressed in a variety of tissues. Moreover, GFER induces the expression of S-adenosylmethionine decarboxyl-ase and ornithine decarboxylases (ODC), which each have a central role in the synthesis of polyamines. The hepatotrophic factor designated augmenter of liver regeneration (ALR) is assumed to be one of the factors responsible for the exceptional regenerative capacity of mammalian liver. The GFER gene is located on chromosome 16 in the interval containing the locus for polycystic kidney disease (PKD1).

PPIL2 is part of the cyclophilin family of peptidylprolyl isomerases which are highly conserved ubiquitous proteins that play an important role in protein folding, immunosuppression by cyclosporin A, and infection of HIV-1 virions. PPIL2 interacts with the proteinase inhibitor eglin c and is localized in the nucleus. PPIL2 increases folding of proteins andcatalyzes the cis-trans isomerization of proline imidic peptide bonds in oligopeptides.

Glycolipid transfer protein (GLTP) accelerates the intermembrane transfer of different glycolipids. GLTP catalyzes the transfer of various glycosphingolipids between membranes however does not catalyze the transfer of phospholipids. GLTP is involved in the intracellular translocation of glucosylceramides. The GLTP protein is similar to bovine and porcine proteins which accelerate transfer of certain glycosphingolipids and glyceroglycolipids between membranes. GLTP is assumed to be a cytoplasmic protein. GLTP is detected in fibroblasts and in various cancer cell lines.

GIMAP6 is a member of the GTPases of immunity-associated proteins (GIMAP) family. GIMAP proteins contain GTP-binding and coiled-coil motifs, and may play roles in the regulation of cell survival. Decreased expression of this gene may play a role in non-small cell lung cancer. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene, which is found in a cluster with seven additional GIMAP genes on the long arm of chromosome 7.

HBsAg is the surface antigenof the Hepatitis-B-Virus (HBV). The capsidof a virus has different surface proteins from the rest of the virus. The antigen is a protein that binds specifically on one of these surface proteins. It is commonly referred to as the Australian Antigen.

Vaspin (visceral adipose-specific SERPIN) is a newly identified adipokine, which is a member of serine protease inhibitor family. Vaspin is also a unique insulin sensitizing adipocytokine in obesity. A recent publication indicates that induction of human vaspin mRNA expression in adipose tissue is regulated in a fat depot-specific manner and could be associated with parameters of obesity, insulin resistance, and glucose metabolism.

HPCAL1, participates in neuron-specific calcium-binding proteins family found in the retina and brain. HPCAL1 is extremely comparable to human hippocalcin protein and almost equal to the rat and mouse hippocalcin like-1 proteins. HPCAL1 takes part in the calcium-dependent regulation of rhodopsin phosphorylation and can have importance in neuronal signalling in the central nervous system.

GADD45GIP1 is a nuclear protein which takes part in apoptosis control. GADD45GIP1 is expressed in several tissues, such as heart, thyroid, trachea, kidney, ovary, pancreas, testis and stomach and acts as a negative regulator of G1 to S phase cell cycle production by collaborating with GADD45 proteins to inhibit the activity of cyclin-dependent kinases.

Growth hormone receptor, also known as GHR is part of the cytokine receptor family. GHR binds 2 receptor molecules and in this manner induces signal transduction through receptor dimerization. Furthermore, at high concentrations, growth hormone performs as an antagonist since there is a large difference in affinities at the respective binding sites. The antagonist action can be enhanced further by reducing binding in the low affinity binding site.

Gastrokine 3 (GKN3P) is a Pseudogene, which May inhibit gastric epithelial cell proliferation.

Peptidoglycan Recognition Protein 1 (PGLYRP1) is a member of the N-acetylmuramoyl-L-alanine amidase 2 family. PGLYRP1 binds to peptidoglycan of bacteria and affects the peptidoglycan biosynthesis. PGLYRP1 displays bactericidal activity towards Gram-positive bacteria and is bacteriostatic towards Gram-negative bacteria. PGLYRP1 has a role in innate immunity. PGLYRP1 is highly expressed in the bone marrow, and weakly expressed in the kidney, liver, small intestine, spleen, thymus, peripheral leukocyte, lung, fetal spleen and neutrophils.

SERPINA1 is secreted and is a serine protease inhibitor which its targets include elastase, plasmin, collagenase, thrombin, leucocytic proteases, trypsin, chymotrypsin, and plasminogen activator. Defects in SERPINA1 gene can cause emphysema or liver disease. Antral SERPINA1 expression is particularly induced by H. pylori infection. lung and prostate cancers have shown a significant increase in SERPINA1 serum levels compared with healthy controls though breast cancers did not show a significant change. SERPINA1 is an endogenous inhibitor of serine proteases and inhibits the catalytic domain of human recombinant matriptase in vitro. Rise in SERPINA1 occurs as an acute phase response to tissue necrosis and inflammation. mutations in SERPINA1 and SLC11A1 genes change the balance between elastase produced by leukocytes during phagocytosis.

Glutaredoxin belongs to the thiol-disulfide oxidoreductase family. Glutraredoxins catalyze the reversible reduction of protein-glutathionyl mixed disulfides to free sulfhydryl groups though a monothiol mechanism. Glutaredoxin-3 (GRX3) is an important protein involved in the regulation of signal transduction, for example during immune cell activation and development of cardiac hypertrophy, apparently in response to redox signals. GRX3 interacts with PRKCQ. GRX3 may have a role in the regulation the function of the thioredoxin system. GRX3 is expressed in the heart, spleen, testis and, to a lower extent, in the thymus and peripheral blood leukocytes. GRX3 is weakly expressed in lung, placenta, colon and small intestine.