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Gastrin
Gastrin is a peptide hormone that stimulates secretion of gastric acid (HCl) by the parietal cells of the stomach and aids in gastric motility. It is released by G cells in the pyloric antrum of the stomach, duodenum, and the pancreas. Gastrin binds to cholecystokinin B receptors to stimulate the release of histamines in enterochromaffin-like cells, and it induces the insertion of K+/H+ ATPase pumps into the apical membrane of parietal cells (which in turn increases H+ release into the stomach cavity). Its release is stimulated by peptides in the Lumen (anatomy), lumen of the stomach. Physiology Genetics In humans, the ''GAS'' gene is located on the long arm of the seventeenth chromosome (17q21). Synthesis Gastrin is a linear peptide hormone produced by G cells of the duodenum and in the pyloric antrum of the stomach. It is secreted into the bloodstream. The encoded polypeptide is preprogastrin, which is cleaved by enzymes in posttranslational modification to produce progastr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastrin Releasing Peptide
Gastrin-releasing peptide, also known as GRP, is a neuropeptide, a regulatory molecule that has been implicated in a number of physiological and pathophysiological processes. Most notably, GRP stimulates the release of gastrin from the G cells of the stomach. The gene from which GRP is derived encodes a number of bombesin-like peptides. Its 148-amino acid preproprotein, following cleavage of a signal peptide, is further processed to produce either the 27-amino acid gastrin-releasing peptide or the 10-amino acid neuromedin C. These smaller peptides regulate numerous functions of the gastrointestinal and central nervous systems, including release of gastrointestinal hormones, smooth muscle cell contraction, and epithelial cell proliferation. Function Gastrin-releasing peptide is a regulatory human peptide that elicits gastrin release and regulates gastric acid secretion and enteric motor function. The post-ganglionic fibers of the vagus nerve that innervate bombesin/GRP neurons o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholecystokinin B Receptor
The cholecystokinin B receptor also known as CCKBR or CCK2 is a protein that in humans is encoded by the ''CCKBR'' gene. This gene encodes a G protein-coupled receptor for gastrin and cholecystokinin (CCK), regulatory peptides of the brain and gastrointestinal tract. This protein is a type B gastrin receptor, which has a high affinity for both sulfated and nonsulfated CCK analogs and is found principally in the central nervous system and the gastrointestinal tract. A misspliced transcript variant including an intron has been observed in cells from colorectal and pancreatic tumors. CNS effects CCK receptors significantly influence neurotransmission in the brain, regulating anxiety, feeding, and locomotion. CCK-B expression may correlate parallel to anxiety and depression phenotypes in humans. CCK-B receptors possess a complex regulation of dopamine activity in the brain. CCK-B activation appears to possess a general inhibitory action on dopamine activity in the brain, opposing t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentagastrin
Pentagastrin (trade name Peptavlon) is a synthetic polypeptide that has effects like gastrin when given parenterally. It stimulates the secretion of gastric acid, pepsin, and intrinsic factor, and has been used as a diagnostic aid as the pentagastrin-stimulated calcitonin test. Pentagastrin binds to the cholecystokinin-B receptor, which is expressed widely in the brain. Activation of these receptors activates the phospholipase C second messenger system. When given intravenously it may cause panic attacks. Pentagastrin's IUPAC chemical name is "N-((1,1-dimethylethoxy)carbonyl)-beta-alanyl-L-tryptophyl-L-methionyl-L-alpha-aspartyl-L-phenylalaninamide". Pentagastrin stimulation test Pentagastrin is also used as a stimulation test to elevate of several hormones, such as serotonin. It provokes flushing and is useful in evaluating patients who describe flushing, but have normal or only marginally elevated biochemical markers for carcinoid syndrome. It has been used to stimulate ect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Minigastrin
Minigastrin (also mini gastrin) is a form of gastrin. Its sequence is H-Leu-Glu-Glu-Glu-Glu-Glu-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2. Minigastrin has shown to be a potential therapeutic agent for thyroid carcinoma by targeting cancer-promoting cholecystokinin receptors. A 2018 study further elaborates by using radiochemical labeling to show that Indium-111 labeled minigastrin peptides showing to have stronger affinity to cholecystokinin B receptor The cholecystokinin B receptor also known as CCKBR or CCK2 is a protein that in humans is encoded by the ''CCKBR'' gene. This gene encodes a G protein-coupled receptor for gastrin and cholecystokinin (CCK), regulatory peptides of the brain and g ...s (CCK2) in neuroendocrine cancers. Biological Applications ''Peptide Receptor Radionuclide Therapy (PRRT)'' A radioactively labeled analogue of minigastrin, PP-F11, conjugated with NOTA, DOTA, or NODAGA was studied to view the effects they have on peptide receptor radionuclide therapy (PRR ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastrin-14
Minigastrin (also mini gastrin) is a form of gastrin. Its sequence is H-Leu-Glu-Glu-Glu-Glu-Glu-Ala-Tyr-Gly-Trp-Met-Asp-Phe-NH2. Minigastrin has shown to be a potential therapeutic agent for thyroid carcinoma by targeting cancer-promoting cholecystokinin receptors. A 2018 study further elaborates by using radiochemical labeling to show that Indium, Indium-111 labeled minigastrin peptides showing to have stronger affinity to cholecystokinin B receptors (CCK2) in neuroendocrine cancers. Biological Applications ''Peptide Receptor Radionuclide Therapy (PRRT)'' A radioactively labeled analogue of minigastrin, PP-F11, conjugated with NOTA, DOTA, or NODAGA was studied to view the effects they have on peptide receptor radionuclide therapy (PRRT) and cancer cell tracing. When mice with CCK2 tumors were injected with 64Cu-labeled DOTA-PP-F11, NOTA-PP-F11, and NODAGA-PP-F11, the mice labeled with NOTA displayed a tumor uptake o 7.20 ± 0.44% ID/g and a high tumor-to-blood ratio. Further ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastrin-34
Big gastrin (G-34) is a form of gastrin with 34 amino acids in its sequence. Big gastrin is a hormone produced by G cells and can be found inside of the stomach. G-34 promotes the secretion of gastric acid in dogs. In dogs, the half life of this peptide is between 14.7 and 16.8 minutes. In humans, an over production of this hormone by gastrinomas leads to Zollinger-Ellison Syndrome. Big Gastrin Responses to Foods: Big gastrin (G34) is one form of gastrin predominate in circulation after a meal, another major form is called little gastrin (G17). Both forms of gastrin have been isolated from human gastrinoma and hog antral mucosa. G34 is carboxy-amidated and can be sulphated or unsulphated at the tyrosin residues. Binding of gastrin to the receptors in stomach can cause the secretion of hydrochloric acids (HCl), the gastric acid. Duodenal ulcer patients tend to have higher than normal basal and maximal rate of gastric acid secretion, while gastric ulcer patients have lower than no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Big Gastrin
Big gastrin (G-34) is a form of gastrin with 34 amino acids in its sequence. Big gastrin is a hormone produced by G cells and can be found inside of the stomach. G-34 promotes the secretion of gastric acid in dogs. In dogs, the half life of this peptide is between 14.7 and 16.8 minutes. In humans, an over production of this hormone by gastrinomas leads to Zollinger-Ellison Syndrome. Big Gastrin Responses to Foods: Big gastrin (G34) is one form of gastrin predominate in circulation after a meal, another major form is called little gastrin (G17). Both forms of gastrin have been isolated from human gastrinoma and hog antral mucosa. G34 is carboxy-amidated and can be sulphated or unsulphated at the tyrosin residues. Binding of gastrin to the receptors in stomach can cause the secretion of hydrochloric acids (HCl), the gastric acid. Duodenal ulcer patients tend to have higher than normal basal and maximal rate of gastric acid secretion, while gastric ulcer patients have lower than nor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastric Acid
Gastric acid, gastric juice, or stomach acid is a digestive fluid formed within the stomach lining. With a pH between 1 and 3, gastric acid plays a key role in digestion of proteins by activating digestive enzymes, which together break down the long chains of amino acids of proteins. Gastric acid is regulated in feedback systems to increase production when needed, such as after a meal. Other cells in the stomach produce bicarbonate, a base, to buffer the fluid, ensuring a regulated pH. These cells also produce mucus – a viscous barrier to prevent gastric acid from damaging the stomach. The pancreas further produces large amounts of bicarbonate and secretes bicarbonate through the pancreatic duct to the duodenum to neutralize gastric acid passing into the digestive tract. The active components of gastric acid are protons and chloride. Often simplistically described as hydrochloric acid, these species are produced by parietal cells in the gastric glands in the stomach. The sec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Little Gastrin
Little gastrin I is a form of gastrin Gastrin is a peptide hormone that stimulates secretion of gastric acid (HCl) by the parietal cells of the stomach and aids in gastric motility. It is released by G cells in the pyloric antrum of the stomach, duodenum, and the pancreas. Gastrin ... commonly called as gastrin-17. This is a protein hormone, secreted by the intestine. Gastrin II has identical amino acid composition to Gastrin I, the only difference is that the single tyrosine residue is sulfated in Gastrin II. References Peptide hormones {{biochem-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parietal Cells
Parietal cells (also known as oxyntic cells) are epithelial cells in the stomach that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and body regions of the stomach. They contain an extensive secretory network of canaliculi from which the HCl is secreted by active transport into the stomach. The enzyme hydrogen potassium ATPase (H+/K+ ATPase) is unique to the parietal cells and transports the H+ against a concentration gradient of about 3 million to 1, which is the steepest ion gradient formed in the human body. Parietal cells are primarily regulated via histamine, acetylcholine and gastrin signalling from both central and local modulators. Structure Canaliculus A canaliculus is an adaptation found on gastric parietal cells. It is a deep infolding, or little channel, which serves to increase the surface area, e.g. for secretion. The parietal cell membrane is dynamic; the numbers of canalic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G Cell
In anatomy, the G cell or gastrin cell, is a type of cell in the stomach and duodenum that secretes gastrin. It works in conjunction with gastric chief cells and parietal cells. G cells are found deep within the pyloric glands of the stomach antrum, and occasionally in the pancreas and duodenum. The vagus nerve innervates the G cells. Gastrin-releasing peptide is released by the post-ganglionic fibers of the vagus nerve onto G cells during parasympathetic stimulation. The peptide hormone bombesin also stimulates gastrin from G cells. Gastrin-releasing peptide, as well as the presence of amino acids in the stomach, stimulates the release of gastrin from the G cells. Gastrin stimulates enterochromaffin-like cells to secrete histamine. Gastrin also targets parietal cells by increasing the amount of histamine and the direct stimulation by gastrin, causing the parietal cells to increase HCl secretion in the stomach. G-cells frequently express PD-L1 during homeostasis which protects them f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digestion
Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions. In chemical digestion, enzymes break down food into the small molecules the body can use. In the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication (chewing), a form of mechanical digestion, and the wetting contact o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
