Gastrins
A family of gastrointestinal peptide hormones that excite the secretion of GASTRIC JUICE. They may also occur in the central nervous system where they are presumed to be neurotransmitters.
Peptides
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
Receptors, Cholecystokinin
Cell surface proteins that bind cholecystokinin (CCK) with high affinity and trigger intracellular changes influencing the behavior of cells. Cholecystokinin receptors are activated by GASTRIN as well as by CCK-4; CCK-8; and CCK-33. Activation of these receptors evokes secretion of AMYLASE by pancreatic acinar cells, acid and PEPSIN by stomach mucosal cells, and contraction of the PYLORUS and GALLBLADDER. The role of the widespread CCK receptors in the central nervous system is not well understood.
Receptor, Cholecystokinin B
A subtype of cholecystokinin receptor found primarily in the CENTRAL NERVOUS SYSTEM and the GASTRIC MUCOSA. It may play a role as a neuromodulator of dopaminergic neurotransmission the regulation of GASTRIC ACID secretion from GASTRIC PARIETAL CELLS.
Peptide Fragments
Peptide Library
A collection of cloned peptides, or chemically synthesized peptides, frequently consisting of all possible combinations of amino acids making up an n-amino acid peptide.
Pyloric Antrum
Antimicrobial Cationic Peptides
Small cationic peptides that are an important component, in most species, of early innate and induced defenses against invading microbes. In animals they are found on mucosal surfaces, within phagocytic granules, and on the surface of the body. They are also found in insects and plants. Among others, this group includes the DEFENSINS, protegrins, tachyplesins, and thionins. They displace DIVALENT CATIONS from phosphate groups of MEMBRANE LIPIDS leading to disruption of the membrane.
Gastric Acid
Hydrochloric acid present in GASTRIC JUICE.
Peptides, Cyclic
Peptides whose amino and carboxy ends are linked together with a peptide bond forming a circular chain. Some of them are ANTI-INFECTIVE AGENTS. Some of them are biosynthesized non-ribosomally (PEPTIDE BIOSYNTHESIS, NON-RIBOSOMAL).
Gastric Mucosa
Lining of the STOMACH, consisting of an inner EPITHELIUM, a middle LAMINA PROPRIA, and an outer MUSCULARIS MUCOSAE. The surface cells produce MUCUS that protects the stomach from attack by digestive acid and enzymes. When the epithelium invaginates into the LAMINA PROPRIA at various region of the stomach (CARDIA; GASTRIC FUNDUS; and PYLORUS), different tubular gastric glands are formed. These glands consist of cells that secrete mucus, enzymes, HYDROCHLORIC ACID, or hormones.
Gastric Juice
The liquid secretion of the stomach mucosa consisting of hydrochloric acid (GASTRIC ACID); PEPSINOGENS; INTRINSIC FACTOR; GASTRIN; MUCUS; and the bicarbonate ion (BICARBONATES). (From Best & Taylor's Physiological Basis of Medical Practice, 12th ed, p651)
Gastrin-Releasing Peptide
Neuropeptide and gut hormone that helps regulate GASTRIC ACID secretion and motor function. Once released from nerves in the antrum of the STOMACH, the neuropeptide stimulates release of GASTRIN from the GASTRIN-SECRETING CELLS.
Cholecystokinin
A peptide, of about 33 amino acids, secreted by the upper INTESTINAL MUCOSA and also found in the central nervous system. It causes gallbladder contraction, release of pancreatic exocrine (or digestive) enzymes, and affects other gastrointestinal functions. Cholecystokinin may be the mediator of satiety.
Zollinger-Ellison Syndrome
A syndrome that is characterized by the triad of severe PEPTIC ULCER, hypersecretion of GASTRIC ACID, and GASTRIN-producing tumors of the PANCREAS or other tissue (GASTRINOMA). This syndrome may be sporadic or be associated with MULTIPLE ENDOCRINE NEOPLASIA TYPE 1.
Pentagastrin
A synthetic pentapeptide 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.
Gastrin-Secreting Cells
Endocrine cells which secrete GASTRIN, a peptide that induces GASTRIC ACID secretion. They are found predominantly in the GASTRIC GLANDS of PYLORIC ANTRUM in the STOMACH, but can also be found in the DUODENUM, nervous and other tissues.
Peptide Mapping
Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.
Oligopeptides
Peptides composed of between two and twelve amino acids.
Amino Acid Sequence
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Somatostatin
A 14-amino acid peptide named for its ability to inhibit pituitary GROWTH HORMONE release, also called somatotropin release-inhibiting factor. It is expressed in the central and peripheral nervous systems, the gut, and other organs. SRIF can also inhibit the release of THYROID-STIMULATING HORMONE; PROLACTIN; INSULIN; and GLUCAGON besides acting as a neurotransmitter and neuromodulator. In a number of species including humans, there is an additional form of somatostatin, SRIF-28 with a 14-amino acid extension at the N-terminal.
Benzodiazepinones
Natriuretic Peptide, Brain
A PEPTIDE that is secreted by the BRAIN and the HEART ATRIA, stored mainly in cardiac ventricular MYOCARDIUM. It can cause NATRIURESIS; DIURESIS; VASODILATION; and inhibits secretion of RENIN and ALDOSTERONE. It improves heart function. It contains 32 AMINO ACIDS.
Enterochromaffin-like Cells
Neuroendocrine cells in the glands of the GASTRIC MUCOSA. They produce HISTAMINE and peptides such as CHROMOGRANINS. ECL cells respond to GASTRIN by releasing histamine which acts as a paracrine stimulator of the release of HYDROCHLORIC ACID from the GASTRIC PARIETAL CELLS.
Vasoactive Intestinal Peptide
A highly basic, 28 amino acid neuropeptide released from intestinal mucosa. It has a wide range of biological actions affecting the cardiovascular, gastrointestinal, and respiratory systems and is neuroprotective. It binds special receptors (RECEPTORS, VASOACTIVE INTESTINAL PEPTIDE).
Stomach
An organ of digestion situated in the left upper quadrant of the abdomen between the termination of the ESOPHAGUS and the beginning of the DUODENUM.
Duodenal Ulcer
A PEPTIC ULCER located in the DUODENUM.
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Secretin
A peptide hormone of about 27 amino acids from the duodenal mucosa that activates pancreatic secretion and lowers the blood sugar level. (USAN and the USP Dictionary of Drug Names, 1994, p597)
Enterochromaffin Cells
A subtype of enteroendocrine cells found in the gastrointestinal MUCOSA, particularly in the glands of PYLORIC ANTRUM; DUODENUM; and ILEUM. These cells secrete mainly SEROTONIN and some neuropeptides. Their secretory granules stain readily with silver (argentaffin stain).
Histidine Decarboxylase
An enzyme that catalyzes the decarboxylation of histidine to histamine and carbon dioxide. It requires pyridoxal phosphate in animal tissues, but not in microorganisms. EC 4.1.1.22.
Parietal Cells, Gastric
Protein Precursors
Protein precursors, also known as proproteins or prohormones, are inactive forms of proteins that undergo post-translational modification, such as cleavage, to produce the active functional protein or peptide hormone.
Protein Binding
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Peptide YY
A 36-amino acid peptide produced by the L cells of the distal small intestine and colon. Peptide YY inhibits gastric and pancreatic secretion.
Calcitonin Gene-Related Peptide
Calcitonin gene-related peptide. A 37-amino acid peptide derived from the calcitonin gene. It occurs as a result of alternative processing of mRNA from the calcitonin gene. The neuropeptide is widely distributed in neural tissue of the brain, gut, perivascular nerves, and other tissue. The peptide produces multiple biological effects and has both circulatory and neurotransmitter modes of action. In particular, it is a potent endogenous vasodilator.
Radioimmunoassay
Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.
Cell-Penetrating Peptides
Sincalide
An octapeptide hormone present in the intestine and brain. When secreted from the gastric mucosa, it stimulates the release of bile from the gallbladder and digestive enzymes from the pancreas.
Gastrointestinal Hormones
Peptide Biosynthesis
The production of PEPTIDES or PROTEINS by the constituents of a living organism. The biosynthesis of proteins on RIBOSOMES following an RNA template is termed translation (TRANSLATION, GENETIC). There are other, non-ribosomal peptide biosynthesis (PEPTIDE BIOSYNTHESIS, NUCLEIC ACID-INDEPENDENT) mechanisms carried out by PEPTIDE SYNTHASES and PEPTIDYLTRANSFERASES. Further modifications of peptide chains yield functional peptide and protein molecules.
Anemia, Pernicious
A megaloblastic anemia occurring in children but more commonly in later life, characterized by histamine-fast achlorhydria, in which the laboratory and clinical manifestations are based on malabsorption of vitamin B 12 due to a failure of the gastric mucosa to secrete adequate and potent intrinsic factor. (Dorland, 27th ed)
Peptide Nucleic Acids
DNA analogs containing neutral amide backbone linkages composed of aminoethyl glycine units instead of the usual phosphodiester linkage of deoxyribose groups. Peptide nucleic acids have high biological stability and higher affinity for complementary DNA or RNA sequences than analogous DNA oligomers.
Motilin
A peptide of about 22-amino acids isolated from the DUODENUM. At low pH it inhibits gastric motor activity, whereas at high pH it has a stimulating effect.
Achlorhydria
A lack of HYDROCHLORIC ACID in GASTRIC JUICE despite stimulation of gastric secretion.
Binding Sites
Base Sequence
Natriuretic Peptide, C-Type
A PEPTIDE of 22 amino acids, derived mainly from cells of VASCULAR ENDOTHELIUM. It is also found in the BRAIN, major endocrine glands, and other tissues. It shares structural homology with ATRIAL NATRIURETIC FACTOR. It has vasorelaxant activity thus is important in the regulation of vascular tone and blood flow. Several high molecular weight forms containing the 22 amino acids have been identified.
Protein Conformation
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Peptide PHI
A 27-amino acid peptide with histidine at the N-terminal and isoleucine amide at the C-terminal. The exact amino acid composition of the peptide is species dependent. The peptide is secreted in the intestine, but is found in the nervous system, many organs, and in the majority of peripheral tissues. It has a wide range of biological actions, affecting the cardiovascular, gastrointestinal, respiratory, and central nervous systems.
Natriuretic Peptides
Peptides that regulate the WATER-ELECTROLYTE BALANCE in the body, also known as natriuretic peptide hormones. Several have been sequenced (ATRIAL NATRIURETIC FACTOR; BRAIN NATRIURETIC PEPTIDE; C-TYPE NATRIURETIC PEPTIDE).
Chromatography, High Pressure Liquid
Models, Molecular
Secretory Rate
The amount of a substance secreted by cells or by a specific organ or organism over a given period of time; usually applies to those substances which are formed by glandular tissues and are released by them into biological fluids, e.g., secretory rate of corticosteroids by the adrenal cortex, secretory rate of gastric acid by the gastric mucosa.
Proglumide
Protein Structure, Secondary
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
Receptors, Formyl Peptide
A family of G-protein-coupled receptors that was originally identified by its ability to bind N-formyl peptides such as N-FORMYLMETHIONINE LEUCYL-PHENYLALANINE. Since N-formyl peptides are found in MITOCHONDRIA and BACTERIA, this class of receptors is believed to play a role in mediating cellular responses to cellular damage and bacterial invasion. However, non-formylated peptide ligands have also been found for this receptor class.
Peptide Synthases
Ligases that catalyze the joining of adjacent AMINO ACIDS by the formation of carbon-nitrogen bonds between their carboxylic acid groups and amine groups.
Histamine
Peptide Hydrolases
Receptors, Peptide
Pancreatic Polypeptide
A 36-amino acid pancreatic hormone that is secreted mainly by endocrine cells found at the periphery of the ISLETS OF LANGERHANS and adjacent to cells containing SOMATOSTATIN and GLUCAGON. Pancreatic polypeptide (PP), when administered peripherally, can suppress gastric secretion, gastric emptying, pancreatic enzyme secretion, and appetite. A lack of pancreatic polypeptide (PP) has been associated with OBESITY in rats and mice.
Atrial Natriuretic Factor
A potent natriuretic and vasodilatory peptide or mixture of different-sized low molecular weight PEPTIDES derived from a common precursor and secreted mainly by the HEART ATRIUM. All these peptides share a sequence of about 20 AMINO ACIDS.
Mass Spectrometry
Structure-Activity Relationship
Tetragastrin
Devazepide
A derivative of benzodiazepine that acts on the cholecystokinin A (CCKA) receptor to antagonize CCK-8's (SINCALIDE) physiological and behavioral effects, such as pancreatic stimulation and inhibition of feeding.
Trypsin
A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.
Vagotomy
The interruption or removal of any part of the vagus (10th cranial) nerve. Vagotomy may be performed for research or for therapeutic purposes.
Amino Acids
Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.
Peptide Hormones
Hormones synthesized from amino acids. They are distinguished from INTERCELLULAR SIGNALING PEPTIDES AND PROTEINS in that their actions are systemic.
Sequence Homology, Amino Acid
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Gastric Fundus
The superior portion of the body of the stomach above the level of the cardiac notch.
Pepsinogens
Proenzymes secreted by chief cells, mucous neck cells, and pyloric gland cells, which are converted into pepsin in the presence of gastric acid or pepsin itself. (Dorland, 28th ed) In humans there are 2 related pepsinogen systems: PEPSINOGEN A (formerly pepsinogen I or pepsinogen) and PEPSINOGEN C (formerly pepsinogen II or progastricsin). Pepsinogen B is the name of a pepsinogen from pigs.
Glucagon-Like Peptides
Peptides derived from proglucagon which is also the precursor of pancreatic GLUCAGON. Despite expression of proglucagon in multiple tissues, the major production site of glucagon-like peptides (GLPs) is the INTESTINAL L CELLS. GLPs include glucagon-like peptide 1, glucagon-like peptide 2, and the various truncated forms.
Peptones
Chromogranin A
A type of chromogranin which was first isolated from CHROMAFFIN CELLS of the ADRENAL MEDULLA but is also found in other tissues and in many species including human, bovine, rat, mouse, and others. It is an acidic protein with 431 to 445 amino acid residues. It contains fragments that inhibit vasoconstriction or release of hormones and neurotransmitter, while other fragments exert antimicrobial actions.
RNA, Messenger
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Gastric Fistula
Abnormal passage communicating with the STOMACH.
Binding, Competitive
Dogs
Chromogranins
A group of acidic proteins that are major components of SECRETORY GRANULES in the endocrine and neuroendocrine cells. They play important roles in the aggregation, packaging, sorting, and processing of secretory protein prior to secretion. They are cleaved to release biologically active peptides. There are various types of granins, usually classified by their sources.
Receptor, Cholecystokinin A
A subtype of cholecystokinin receptor found primarily in the PANCREAS; STOMACH; INTESTINE; and GALLBLADDER. It plays a role in regulating digestive functions such as gallbladder contraction, pancreatic enzyme secretion and absorption in the GASTROINTESTINAL TRACT.
Dose-Response Relationship, Drug
Cloning, Molecular
Opioid Peptides
The endogenous peptides with opiate-like activity. The three major classes currently recognized are the ENKEPHALINS, the DYNORPHINS, and the ENDORPHINS. Each of these families derives from different precursors, proenkephalin, prodynorphin, and PRO-OPIOMELANOCORTIN, respectively. There are also at least three classes of OPIOID RECEPTORS, but the peptide families do not map to the receptors in a simple way.
Gastrinoma
A GASTRIN-secreting neuroendocrine tumor of the non-beta ISLET CELLS, the GASTRIN-SECRETING CELLS. This type of tumor is primarily located in the PANCREAS or the DUODENUM. Majority of gastrinomas are malignant. They metastasize to the LIVER; LYMPH NODES; and BONE but rarely elsewhere. The presence of gastrinoma is one of three requirements to be met for identification of ZOLLINGER-ELLISON SYNDROME, which sometimes occurs in families with MULTIPLE ENDOCRINE NEOPLASIA TYPE 1; (MEN 1).
Intracellular Signaling Peptides and Proteins
Proteins and peptides that are involved in SIGNAL TRANSDUCTION within the cell. Included here are peptides and proteins that regulate the activity of TRANSCRIPTION FACTORS and cellular processes in response to signals from CELL SURFACE RECEPTORS. Intracellular signaling peptide and proteins may be part of an enzymatic signaling cascade or act through binding to and modifying the action of other signaling factors.
Pepsin A
Formed from pig pepsinogen by cleavage of one peptide bond. The enzyme is a single polypeptide chain and is inhibited by methyl 2-diaazoacetamidohexanoate. It cleaves peptides preferentially at the carbonyl linkages of phenylalanine or leucine and acts as the principal digestive enzyme of gastric juice.
Protein Processing, Post-Translational
Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.
Protein Structure, Tertiary
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Cells, Cultured
Duodenum
The shortest and widest portion of the SMALL INTESTINE adjacent to the PYLORUS of the STOMACH. It is named for having the length equal to about the width of 12 fingers.
Substrate Specificity
Hydrogen-Ion Concentration
Proteins
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
Pancreatic Hormones
Peptide hormones secreted into the blood by cells in the ISLETS OF LANGERHANS of the pancreas. The alpha cells secrete glucagon; the beta cells secrete insulin; the delta cells secrete somatostatin; and the PP cells secrete pancreatic polypeptide.
Glucagon-Like Peptide 1
A peptide of 36 or 37 amino acids that is derived from PROGLUCAGON and mainly produced by the INTESTINAL L CELLS. GLP-1(1-37 or 1-36) is further N-terminally truncated resulting in GLP-1(7-37) or GLP-1-(7-36) which can be amidated. These GLP-1 peptides are known to enhance glucose-dependent INSULIN release, suppress GLUCAGON release and gastric emptying, lower BLOOD GLUCOSE, and reduce food intake.
Pancreas
A nodular organ in the ABDOMEN that contains a mixture of ENDOCRINE GLANDS and EXOCRINE GLANDS. The small endocrine portion consists of the ISLETS OF LANGERHANS secreting a number of hormones into the blood stream. The large exocrine portion (EXOCRINE PANCREAS) is a compound acinar gland that secretes several digestive enzymes into the pancreatic ductal system that empties into the DUODENUM.
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis.
Cattle
Molecular Mimicry
Escherichia coli
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.