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Glucagon is a member of a multigene family comprising of Secretin, Vasoactive Intestinal Peptide (VIP), Gastric Inhibitory Peptide (GIP) and others like Glicentin and Oxyntomodulin (OXM), which differs from glucagon by C-terminal octapeptide. The glucagon precursor contains at least 3 intervening sequences that divide the protein-coding portion into 4 regions corresponding to the signal peptide and part of the N-terminal peptide, the remainder of the N-terminal peptide and glucagon, glucagon-like peptide-1 (GLP1), and GLP2. The GLP 1 & 2 stimulates intestinal growth and up regulates villus height in the small intestine, concomitant with increased crupt cell proliferation and decreased enterocyte apoptosis. The two GLP's are mainly produced in the A cells of the Islets of Langerhans in response to a drop in blood sugar concentration.

Glucagon (GLGN) is a 29aa pancreatic hormone (chr 2q36), which together with insulin, is an important regulator of glucose metabolism. When in need of glucose, glucagon is secreted by the A cells of the pancreas and binds to target cell-surface receptors in the liver. This triggers a series of events that ultimately results in glycogenolysis and gluconeogenesis and a consequent rise in glucose levels in the blood. The glucagons in Human, rabbit, rat, pig and cow are identical.

GLP1, a processed active peptide of 30aa (chr 2q36-q37) is a potent insulin secretagogue, plays a major role in the enteroinsular axis, accounting for the finding that plasma insulin levels accompanying oral intake of glucose are greater than those observed when glucose is given intravenously. The so-called gluco-incretin.

GLP1 Receptor, a 489aa peptide in mouse, 463aa in rat and human (chr 6p21), it serves as receptor for GLP1. The activity of this receptor is mediated by G protein which activate adenylyl cyclase. GLP1 Receptor is mainly expressed in pancreatic islets, stomach, and lung.

GLP2, also a processed active peptide with 33aa, (chr 2q36-q37). GLP2 regulates gastric motility, gastric acid secretion, intestinal hexose transport, and increases the barrier function of the gut epithelium. It significantly enhances the surface area of the mucosal epithelium via stimulation of crypt cell proliferation. The actions of GLP2 are transduced by the GLP2 receptor, a G-protein-coupled receptor, activation of receptor signaling in heterologous cells promotes resistance to apoptotic injury in vitro, as such it may potentially be useful in treatment of injury and dysfunction of intestinal mucosal epithelium.

GLP2 Receptor, a 550aa protein in rat and 553aa in human (chr 17p13.3). Functions as a receptor for GLP2, the activity is mediated by G proteins which activates the adenylyl cyclase, GLP2 Receptor is expressed in gut and closely related to the receptor for GLP1 (GLP1R).

OXM, a 37 aa peptide contains the glucagon sequence extended by a C-terminal basic octapeptide, its primary structure is identical in all mammals except in pig and cattle. OXM is released from the gut during digestion, together with glicentin another octapeptide containing molecule. It is considered as a putative physiological regulator of gastric acid secretion, it inhibits histamine.

GIP, Gastric inhibitory polypeptide, also known as glucose-dependent insulinotropic polypeptide (GIP), is a 42-amino acid hormone (chr 17q21.3) that stimulates insulin secretion in the presence of glucose. GIP is derived by proteolytic processing of a 153-residue precursor, preproGIP; it is a member of a family of structurally related hormones that includes secretin, glucagon, vasoactive intestinal peptide, and growth hormone-releasing factor.

SECR, Secretin is a 27-amino acid hormone (chr 11p15) produced by specific endocrine cells, S cells, located in the mucosa of the proximal small intestine. It has been known to be a potent stimulus for the secretion of bicarbonate-rich pancreatic juice. Secretion of secretin is stimulated by the presence of either acidic pH or fatty acids in the duodenum. Secretin stimulates ductal bile secretion by directly interacting with cholangiocytes, promotes osmotic water movement in cholangiocytes by inducing the exocytic insertion of AQP1 into plasma membranes.

GRF (Growth hormone-releasing factor) 44 aa peptide (chr 20q11.2) with a mass of 13kD is released by the hypothalamus and acts on the adenohypophyse to stimulate the secretion of Growth Hormone, GRF is mainly secreted by pancreatic islet cells, its antagonists inhibit the growth of various cancers in vivo. This effect is exerted in part by endocrine mechanisms through the inhibition of growth hormone (GH) release from the pituitary.

Rb=Rabbit; m=mouse; r=rat; h=human; b=bovine; c=chicken; d=dog; gp=guinea pig; ~CT or ~NT=near C or N-terminus. EC=Extracellular; CL=Cytoplasmic loop;

* Expected antibody crossreactivity information is mostly based upon high (>70%) sequence conservation of antigenic/control peptides in various species. When antibody crossreactivity has actually been experimentally confirmed in various species, it will be mentioned in the appropriate data sheets.

"Neat Antisera or antisera" are the unpurified antiserum and it is suitable for ELISA and Western.
"Affinity pure" IgG may be more suitable for immunohistochemical (IHC) applications and to reduce background in most immunological applications including ELISA and Western.
"Control peptides" can not be used for Western as they are very short peptides. They are intended for ELISA or antibody blocking studies to establish antibody specificity.
Western blot +ve protein controls, where available, are semi-pure, pure or recombinant proteins that are formulated in SDS-PAGE sample buffer. They are recommended to be used for Western (load 10 ul/lane) for visualization with antibodies

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