Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01350 (gastrin)
 9,683 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intrinsic factor is produced by the gastric parietal cell. Its secretion is stimulated via all pathways known to stimulate gastric acid secretion: histamine, gastrin, and acetylcholine. There is, however, a different mode of secretion for both substances: atropine, vagotomy, and H2 receptor antagonists inhibit both intrinsic factor and acid secretion, but secretin and the hydrogen-potassium ATPase antagonist omeprazole have no effect on intrinsic factor while substantially reducing acid secretion. Cobalamin in food is bound to animal protein. Cobalamin deficiency due to inadequate dietary intake is rarely seen in extreme vegetarians (vegans). In the stomach cobalamin is liberated from its protein binding by peptic digestion and bound to R-proteins. Hypochlorhydria or achlorhydria, whether medically induced or not, may impair cobalamin uptake. The cobalamin-R-protein complex is split by pancreatic enzymes in the duodenum, where cobalamin is bound to intrinsic factor. Pancreatic insufficiency may lead to cobalamin deficiency. Lack of intrinsic factor is the commonest cause of cobalamin deficiency; very rarely, aberrant forms of intrinsic factor are produced, but the clinical syndrome is similar. Gram-negative anaerobe bacteria bind the cobalamin-intrinsic factor complex, and bacterial overgrowth of the small intestine diminishes cobalamin resorption. Parasitic infections with fish tape-worm and Giardia lamblia are also associated with cobalamin malabsorption. The cobalamin-intrinsic factor complex binds to the ileal receptors in the terminal ileum. Cobalamin absorption may be impaired after resection or by diseases affecting more than 50 cm of the terminal ileum, such as Crohn's disease, coeliac disease, tuberculosis, lymphoma or radiation. There is clearly a wide diversity in the aetiology of cobalamin deficiency, which requires a versatile diagnostic approach.
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PMID:Intrinsic factor secretion and cobalamin absorption. Physiology and pathophysiology in the gastrointestinal tract. 177 33

We report on five cases of mucosal atrophy of the gastric body, under the aspect of a polyposis: These polyps showed intact mucosa with abundant fundic glands and were situated in the diffuse atrophic mucosa of the gastric body. Four of these cases were manifestations of type A gastritis, in one case the lesion surrounded a peptic ulcer. Laboratory findings of serologically analysed cases with type A gastritis showed elevated parietal cell antibodies in all cases, two of three cases showed a high level of gastrin, the values for vitamin B12 showed different levels; no patients revealed antibodies against the intrinsic factor, and no patient had pernicious anemia. The family history revealed three cases with cancer of the stomach on one side of the parents. It is important to biopsy polyps and the flat mucosa separately in order to verify this form of atrophy of the gastric mucosa and to also exclude small polypous tumors of the mucosa. Observation of the number of polyps allows a control of the extent of the atrophy of the mucosa.
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PMID:[Atrophy of the corpus mucosa of the stomach simulating polyposis]. 258 39

Omeprazole is the first H+-K+-adenosine triphosphatase antagonist available for clinical use. It has a very strong, long-lasting inhibitory effect on gastric acid secretion. The effect is very selective: pepsin and intrinsic factor secretion are unaffected. Once-daily doses of 30-40 mg cause a more than 95% reduction of intragastric acidity. Lower doses have less predictable results. During treatment with omeprazole serum gastrin levels increase. After cessation of treatment gastric acid secretion and serum gastrin levels rapidly return to pretreatment levels. No rebound phenomena are observed after treatment.
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PMID:Effects of omeprazole on gastric secretory functions. 269 7

Somatostatin (SRIF), a tetradecapeptide, has been reported to suppress gastrin release and hence inhibit acid secretion in vivo. This study was performed to determine whether SRIF has any direct effect on parietal cell (PC). Isolated gastric cells were prepared by collagenase digestion and calcium chelation of rabbit fundic mucosa. PC enrichment (75% +/- 5%) was accomplished by velocity sedimentation with an elutriator rotor. Acid, as assessed by the accumulation of 14C-aminopyrine (AP) and macromolecular (intrinsic factor [IF]) secretion were used as markers of PC function. Cells were stimulated with histamine (H) (10(-6) mol/L). SRIF (10(-10) to 10(-6) mol/L) significantly inhibited H-stimulated 14C-AP accumulation (p less than 0.05). Inhibition of H-stimulated IF release was less sensitive, occurring at 10(-8) and 10(-7) mol/L (p less than 0.05), and loss of inhibition was observed at 10(-6) mol/L (p less than 0.05). These results demonstrate a direct inhibitory action of SRIF on PC secretion. The difference in inhibitory effect on IF and proton secretion is consistent with the postulation that SRIF may function at more than one site within the PC.
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PMID:Evidence for nongastrin-mediated somatostatin inhibition of parietal cell function. 287 98

Pepsinogen (PG) I and PG II levels were determined in sera from 147 patients with pernicious anemia. Race, sex, age, gastrin level, and antibody status did not influence pepsinogen levels. PG I values less than 30 micrograms/L were found in 92% of cases and PG I to PG II ratios less than 3.0 in 82% of cases. At least one of these two results was abnormal in 97% of all patients with pernicious anemia. In comparison, results of other blood tests used in the investigation of pernicious anemia were less often abnormal. Serum gastrin level exceeded 200 ng/L in 90% of patients with pernicious anemia and was second to pepsinogen abnormality in diagnostic sensitivity. Results for anti-intrinsic factor antibody were positive in 73% of cases and anti-parietal cell antibody in only 52%. Although its specificity is limited, the presence of low PG I level and/or low PG I-PG II ratio is currently the most sensitive serum indicator for pernicious anemia, and absence of both can be taken as a strong argument against the diagnosis. This highly sensitive test can be combined further with the highly specific serum anti-intrinsic factor antibody test for the presumptive diagnosis of pernicious anemia when definitive tests (the Schilling test or gastric analysis for intrinsic factor) cannot be done or results are inconclusive.
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PMID:Pepsinogens and other serum markers in pernicious anemia. 317 65

The ratio of pepsinogen I to pepsinogen II in the circulation decreases progressively with increasing severity of atrophic gastritis of the fundic gland mucosa. Fasting blood was obtained from 359 free-living and institutionalized elderly people (age range, 60 to 99 years). A pepsinogen I/pepsinogen II ratio less than 2.9, indicating atrophic gastritis, was found in 113 (31.5%) subjects. The prevalence of atrophic gastritis increased significantly with advancing age (P less than .05). Within the atrophic gastritis group, 84 had a pepsinogen I level greater than or equal to 20 micrograms/L, indicating mild to moderate atrophic gastritis, and 29 had a pepsinogen I level less than 20 micrograms/L, indicating severe atrophic gastritis or gastric atrophy. A significant increase in the prevalences of elevated serum gastrin levels (P less than .005), low serum vitamin B12 levels (P less than .005), circulating intrinsic factor antibody (P less than .005), and anemia (P less than .025) was observed with stepwise increases in severity of atrophic gastritis. Subjects with atrophic gastritis exhibited a lower mean serum vitamin B12 level (P less than .05) and a higher mean folate level (P less than .05), but no difference was detected in mean hemoglobin levels or serum levels of iron, ferritin, retinol or alpha-tocopherol. It is concluded that serum pepsinogen I and pepsinogen II levels can be used to determine the prevalence and severity of atrophic gastritis, that atrophic gastritis is common in an elderly population, and that atrophic gastritis is associated with vitamin B12 deficiency and anemia. Further, higher folate levels in atrophic gastritis may be related to an accumulation of 5-methyl tetrahydrofolate in serum due to vitamin B12 deficiency and/or greater folate synthesis by the intestinal flora resulting from bacterial overgrowth secondary to hypo- or achlorhydria.
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PMID:Fundic atrophic gastritis in an elderly population. Effect on hemoglobin and several serum nutritional indicators. 377 80

A middle-aged woman developed a postgastric bypass megaloblastic anemia which responded to treatment. She eventually had the bypass reversed 6 1/2 yr after it had been performed. Gastric parietal cell function has remained abnormal almost 3 yr after reversal of the bypass, as demonstrated by abnormal Schilling tests and high serum gastrin levels. Parietal cell antibodies in high titer, but no intrinsic factor antibodies, were demonstrated in her blood. These observations are interpreted as indicating the development of irreversible chronic atrophic gastritis probably related to reflux of bile into the bypassed stomach.
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PMID:Chronic parietal cell dysfunction after reversal of gastric bypass. 378 28

Cholecystokinin (CCK), a peptide hormone found in both gut and brain, shares amino acid homologies with gastrin and has previously been shown to stimulate gastric acid secretion in whole animal experiments. To investigate possible direct effects of CCK apart from extrinsic neural and hormonal influences, we have investigated the effects of the sulfated octapeptide of CCK (CCK-8) in rabbit isolated gastric glands using 14C-aminopyrine accumulation and intrinsic factor (IF) secretion as markers of parietal cell function. CCK-8 stimulated a significant increase (p less than 0.05) in IF secretion and 14C-aminopyrine accumulation. IF secretion was dose dependent for CCK concentrations from 10(-10)M to 10(-6)M. The combination of CCK (10(-6)M) and histamine (5 X 10(-5)M) elicited IF secretion greater than that of either agent alone. These results are similar to those observed for pentagastrin (10(-7)M), suggesting that the effects of CCK on parietal cell secretion may be due at least in part to a direct receptor-mediated parietal cell response to this agent.
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PMID:The effects of cholecystokinin on parietal cell secretion in isolated gastric glands. 407 82

Records of the 30 cases of gastric carcinoid at the Mayo Clinic showed that the gastric mucosa was normal, hyperplastic, or atrophic (nonantral) in 12, 2, or 16 patients, respectively. In the atrophic group, the tumors were in the gastric body and fundus; small, polypoid, and multicentric; and associated with fundal argyrophil cell hyperplasia. In immunocytochemical studies, minor tumor cell populations stained positively for 5-hydroxytryptamine, gastrin, and somatostatin in 1 case and for 5-hydroxytryptamine in 3 others. Metastasis occurred in 3 patients. Twelve patients had pernicious anemia. Parietal cell or intrinsic factor antibodies or both were present in all 12 patients tested. Each of the 7 patients with an intact antrum had massive hypergastrinemia. No common HLA-A, -B, or -DR antigen pattern was detected among the 10 patients tested. The results suggest that nonantral gastric atrophy predisposes to gastric carcinoid as well as to gastric carcinoma.
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PMID:The syndrome of gastric argyrophil carcinoid tumors and nonantral gastric atrophy. 619 1

A one-hour infusion of 0.25 micrograms/kg urogastrone administered to seven patients with duodenal ulceration resulted in significant reduction of basal acid secretion (p less than 0.05) but was without significant effect on basal pepsin and intrinsic factor secretion or on serum gastrin concentration. In another group of five patients with duodenal ulceration a one-hour infusion of urogastrone was given on five successive days. On day 1 and 5 urogastrone was administered after establishing a plateau response to intravenous pentagastrin 1.2 micrograms/kg/h. A mean reduction of 65% in acid output during the urogastrtone infusion was seen on day 1 and this was maintained during the next hour. On day 5 the pentagastrin-stimulated acid output was less than on day 1 and a further significant decrease was noted after urogastrone. Pepsin and intrinsic factor output were also significantly inhibited. There was no change in fasting serum gastrin or urogastrone concentration.
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PMID:Effect of urogastrone on gastric secretion and serum gastrin concentration in patients with duodenal ulceration. 681 98


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