Bicarbonate duodenal

The word hormone is derived from the Greek hormaein, meaning to set in motion or to excite. It was used initially to define the activity of secretin [1393-25-5] (1), a gastrointestinal polypeptide released into the blood by the duodenal mucosa to stimulate pancreatic acinar cells to release bicarbonate and water. 

EP3 A mediator of febrile response to pyrogens [19], duodenal bicarbonate secretion [20], suppression of allergic inflammation [21], urinary concentration [22]... 

K. Takeuchi, H. Urawa, S. Kato, O. Fururkawa, H. Araki, Y. Sugimoto, A. Ichikawa, F. Ushikubi, S. Narumiya, Impaired duodenal bicarbonate secretion and mucosal integrity in mice lacking prostaglandin E-receptor subtype EP3, Gastroenterology 117 (1999) 1128. 

The pH-buffering of extracellular fluid depends in part on the carbon dioxide/ bicarbonate equilibrium so that the intake of sodium bicarbonate is followed by a brief alkalosis and an increased excretion of sodium carbonate in the urine. Depending on its carbonate concentration, the pH of the urine may rise to 8.07. Large doses (80—100 g/day) of sodium bicarbonate were needed if the pH of stomach contents was to be maintained at 4 or over in patients with duodenal ulcers8. Oxidation of organic anions in the body to carbon dioxide and water permits the use of sodium citrate, lactate or tartrate instead of sodium bicarbonate. In an analogous manner the ingestion of ammonium chloride induces a brief acidosis as a result of the metabolic conversion of ammonia to urea and lowers the pH of the urine. 

Secretin, isolated from the duodenal mucosa by Jorpes and Mutt 96) in 1961, and 4 years later found to be a linear heptacosapeptide, stimulates the pancreas to produce a bicarbonate-containing secretion. Bodanszky et al. 97), Ondetti et al. 98), and Wiinsch et al. 99) have synthesized secretin derivatives. Another synthesis, by Uchiyama et al. 100) using fragment condensation on a large scale, led within a short time to highly-purified secretin. 

Pharmaceutical inhibition of gastric acid output (proton pump inhibitor, H2 receptor blocker) may have beneficial effects when combined with an unprotected pancreatin preparation, not only by protection of enzymes during their gastric passage, but also by increasing duodenal pH and thereby improving enzymatic action. (Note that, in chronic pancreatitis, duodenal pH is lower due to impairment of pancreatic bicarbonate secretion, see above). 

Glad et al. (1996) tested the influence of gastrinreleasing peptide on acid-induced secretin release and pancreatobiliary and duodenal bicarbonate secretion in Danish country strain pigs weighing between 22 and 30 kg. The animals, starved overnight with free... 

Gastric and duodenal epithelial cells secrete bicarbonate to their apical faces to maintain a neutral pH along the epithelial plasma membrane. 

Misoprostol is a synthetic prostaglandin Ei analogue. It inhibits gastric acid secretion and stimulates the production of mucus and bicarbonate. Misoprostol is as effective as H2 antagonists in healing duodenal ulcers but is less effective in the treatment of gastric ulcers... 

Secretin is a 27-residue peptide amide hormone produced by S cells of the duodenum. The primary effect of secretin is stimulating the release of bicarbonate from liver, pancreas, and duodenal tissues to inhibit gastrin-induced gastric acid release. It also enhances the effects of cholecystokinin and promotes normal growth and maintenance of the pancreas. 

A common duct from the pancreas and gall bladder enters the duodenum. Duodenal pH is 6 to 6.5 due to the presence of bicarbonate that neutralizes the acidic ch5une emptied from the stomach. The pH is optimum for enzymatic digestion of protein and peptide food. Pancreatic juice containing enzymes is secreted into the duodenum from the bile duct. Trypsin, ch5unotrypsin, and carboxypeptidase are involved in the hydrolysis of proteins into amino acids. Amylase is involved in the digestion of carbohydrates. Pancreatic lipase secretion hydrolyzes fats into fatty acids... 

Blockage of the bile duct caused by problems such as cholesterol-containing gallstones or duodenal or pancreatic tumors can lead to an inadequate concentration of bile salts in the intestine. Digestion and absorption of dietary lipids is diminished. Certain diseases that affect the pancreas can lead to a decrease in bicarbonate and digestive enzymes in the intestinal lumen. (Bicarbonate is required to raise the intestinal pH so that bile salts and digestive enzymes can function.) If dietary fats are not adequately digested, steatorrhea may result. Malabsorption of fats can lead to caloric deficiencies and lack of fat-soluble vitamins and essential fatty acids. 

MUSCLE RELAXANT and ANTISPASMODIC properties, secretin ]ban,inn,jan] (porcine secretin Hoe 69 Secretin-Ferring ) is a peptide hormone from duodenal mucosa which stimulates release of bicarbonate from the pancreas. It... 

Flemstrom G, Safsten B. Role of dopamine and other stimuli of mucosal bicarbonate secretion in duodenal protection. Dig Dis Sci 1994 39 1839-42. 

Excessive loss of bicarbonate because of increased renal excretion (decreased tubular reclamation) or excessive loss of duodenal fluid (as in diarrhea). Plasma CHCO3 falls the fall is associated with a rise in the concentration of inorganic anions (mostly chloride) or a concomitant fall in the sodium concentration. 

The pancreas is 12 to 15 cm in length and lies across the posterior wall of the abdominal cavity. The head is located in the duodenal curve the body and tail are directed toward the left, extending to tlie spleen (Figure 48-2). Pancreatic digestive enzymes, in bicarbonate-rich juice, enter the duodenum through the ampulla of Vater and the sphincter of Oddi and mix with the food bolus as it passes through the small bowel. 

Total volume of pancreatic juice, amount or concentration of bicarbonate, and activities of pancreatic enzymes are measured in duodenal contents. The enzyme most commonly measured is trypsin, but amylase, lipase, chy-motrypsin, and elastase may also be evaluated. The Lundh test consists of administering a standardized meal consisting of 5% protein, 6% fat, 15% carbohydrate, and 74% nonnutrient fiber. Advantages of the Lundh meal are that it provides a physiological stimulus to the pancreas and is simple to administer. However, administration of the meal prevents determination of the total enzyme and bicarbonate or secretory volume. Moreover, it provides inadequate or no stimu-... 

The secretin test is based on the principle that secretion of pancreatic juice and bicarbonate output are related to the functional mass of pancreatic tissue. After an overnight fast, basal samples of fluid are collected from the stomach and duodenum. One clinical unit (CU) of secretin/kg body weight is administered intravenously, and duodenal fluid is collected at 15-minute intervals for at least 1 hour. Purified porcine secretin has traditionally been used for the test, but recent studies have confirmed that synthetic porcine secretin (0.2 (Ig/kg) gives results that are not significantly different from results with biologic secretin. ... 

When the products of gastric digestion reach the duodenum, bicarbonate secreted by the pancreas begins to neutralize the stomach acid. The concentration of bicarbonate in pancreatic juice ranges from about 70 to about 150 meq/H (21). In a study involving human subjects, Murthy et al. (22) found the pH of duodenal aspirates to range from 4.7 to 7.2 following administration of a Lundh Test meal. 

IF. Transfer to IF is aided by the bicarbonate of pancreatic juice. At duodenal pH, IF has a greater affinity than cobalophilinforBi2. Patients with pancreatic insufficiency may have vitamin B12 deficiency. 

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