Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024523 (malabsorption)
 7,319 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The importance of the distal small intestine and the ileocecal region for the regulation of gastrointestinal functions in humans has not been investigated in depth until recently. A regulatory role is postulated because even in healthy subjects, undigested nutrients pass across the ileocecal junction after most meals (physiologic malabsorption). Nutrient exposure of the ileocecal region causes slowing of gastric emptying and small intestinal transit, and decrease in small intestinal motor activity; under certain experimental conditions, ileal nutrients induce conversion of intestinal motility from digestive to interdigestive patterns. In addition, the secretory activity of the proximal gastrointestinal tract is inhibited by the ileocecal region. Inhibition of gastric secretion and exocrine pancreatic secretion are well established responses to ileal nutrient exposure; inhibition of bile secretion likely occurs, but is not proven. The intermediary mechanisms of these effects have not been clarified; the most likely candidates include endorphins, peptide YY (PYY), and glucagon-like-peptide-1 (GLP-1). Overall, the available data support the concept that the ileocecal region participates in the physiologic control of gastrointestinal motor and secretory functions. Whether disturbances of these regulatory mechanisms participate in the pathophysiology of gastrointestinal disease has not been investigated.
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PMID:[Regulation of gastrointestinal functions by the ileocecal area]. 148 55

How exocrine pancreatic secretion is regulated is only partly known. It is assumed that interaction of several neural and hormonal mechanisms is involved. In man, the intestinal component of these control mechanisms is very important while extra-intestinal mechanisms (such as the cephalic and the gastric phase) play lesser roles. Regulation of pancreatic secretion by the intestine is composed of three main mechanisms. 1. The proximal intestinal (duodenal) phase of the secretory response to a meal is elicited by nutrients within the proximal intestinal lumen. It is mediated mainly by interactions between cholinergic reflexes and release of the peptide hormone cholecystokinin (CCK). Recent data suggest that part of the action of CCK is not exerted directly on the acinar cellular level, but rather by modulation of cholinergic inputs. 2. The distal intestinal (ileal) phase is elicited by contact of the distal intestinal mucosa with nutrients that pass through the ileal lumen due to physiological malabsorption. The ileum (in contrast to the duodenum) induces net-inhibition of pancreatic secretion. The mediation is unknown, candidate mediators are PYY and GLP-1. 3. Intestinal feedback-regulation of pancreatic secretion in humans is controlled by intraluminal protease activity; this mechanism is not covered in the present paper.
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PMID:[Intestinal regulation of pancreatic enzyme secretion: stimulatory and inhibitory mechanisms]. 150 89

Peptide YY has been localized within human ileocolonic endocrine cells and may contribute to the regulation of gastric secretion and gastric emptying in man. Since our previous studies had shown decreased colonic concentrations of peptide YY in the idiopathic inflammatory bowel diseases, a specific radioimmunoassay was used to measure fasting serum concentrations of peptide YY in healthy controls and in patients with adenocarcinoma of the rectum, idiopathic chronic active liver disease and hepatic cirrhosis, ulcerative colitis, and Crohn's disease. In healthy controls and in patients with adenocarcinoma of the rectum, serum concentrations of peptide YY ranged from 50 to 260 pg/ml. Serum concentrations of peptide YY in patients with hepatic cirrhosis ranged from 59 to 717 pg/ml. Serum concentrations of peptide YY in patients with ulcerative colitis were similar to healthy controls. In patients with Crohn's disease, serum concentrations of peptide YY were less than 50 pg/ml in three patients who had had a previous proctocolectomy, and were more than 260 pg/ml in 14 patients who had had previous resection of more than 48 cm of ileum or presently had symptomatic Crohn's disease subsequently requiring surgical resection of a total of more than 75 cm of ileum. These results suggest that most circulating peptide YY is released from the colorectal region. Hepatic cirrhosis, previous ileal resection, and symptomatic Crohn's disease were associated with elevation of fasting serum peptide YY. The mechanism of increased fasting serum peptide YY in patients with Crohn's disease could be the loss of an ileal inhibitory factor or possibly an increased release of colonic peptide YY in response to fat malabsorption. The effect of alteration of serum peptide YY concentrations on the pathophysiology of Crohn's disease is yet unknown.
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PMID:Abnormalities of fasting serum concentrations of peptide YY in the idiopathic inflammatory bowel diseases. 356 36

Mouth-caecum transit time (M-CTT) of a lactulose labelled liquid test meal has been measured in 27 coeliac patients and 10 healthy controls using the breath hydrogen technique. Although all patients were urged to maintain a gluten free diet, not all did, and there was, therefore, a wide range in the severity of fat malabsorption within the patient group. Gastric emptying of a 113Indium DTPA-labelled liquid test meal was also assessed in separate studies on six healthy controls and 11 of the coeliac patients. Fasting breath hydrogen concentrations and the response to lactulose, as assessed both by the rate of rise, and the peak breath hydrogen concentration reached, showed no difference between coeliacs and controls, regardless of the presence or absence of steatorrhoea. Mouth-caecum transit time in the 16 coeliac patients with steatorrhea (faecal fat greater than 7 g/24 h) was, however, significantly prolonged being 158 +/- 18 minutes (mean +/- SEM), compared with 70 +/- 9 minutes for the controls (p less than 0.02), and 83 +/- 15 minutes for the 11 coeliacs without steatorrhoea (p less than 0.002). Mouth-caecum transit time in the coeliac patients was linearly related to the 24 hour faecal fat excretion, r = 0.55, n = 27, p less than 0.01. Slow mouth-caecum transit in the coeliacs with steatorrhoea was not caused by delayed gastric emptying as the t1/2 for coeliacs with steatorrhoea was within the normal range. Coeliacs with delayed mouth-caecum transit had impaired insulin release but the postprandial profiles of the other peptides measured (cholecystokinin, GIP, secretin, motilin, neurotensin, enteroglucagon, and peptide YY) were all within the normal range in this group of partially treated coeliac patients.
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PMID:Delayed mouth-caecum transit of a lactulose labelled liquid test meal in patients with steatorrhoea caused by partially treated coeliac disease. 367 57

Plasma gastrointestinal hormones were measured before and during feeding in eight dogs, more than one year after total autotransplant of the entire jejunoileum, and in controls. At sacrifice, tissues were taken from the transplanted segment and intact bowel for measurement of hormone and enteric neuropeptide content. Gastrin levels were reduced in autotransplanted dogs (fasting 63% of control, incremental response 67% of control, both P < 0.05), reflecting the loss of acid inhibitory reflexes. Secretin and cholecystokinin responses were identical between the two groups. Postprandial levels of gastric inhibitory peptide (incremental response 175% of control, P < 0.005), insulin, and peptide YY (158% of control, P < 0.05) were elevated following denervation, the former suggesting more rapid gastric emptying while the latter may reflect malabsorption. The neurotensin meal response was obtunded by denervation (incremental response 43% of control, P < 0.05), providing evidence for a neural pathway for its release. Pancreatic polypeptide responses were identical between the groups, suggesting intact pancreatic innervation. Abnormal hormone secretion may contribute to the impaired fed motor responses seen following extrinsic denervation of the small bowel. In contrast, the neuropeptide content of the autotransplanted small intestine is normal, suggesting that extrinsic denervation has no long-term effects on peptide content of the enteric nervous system.
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PMID:Effects of jejunoileal autotransplantation on gastrointestinal regulatory peptides. 795 16

Peptide YY is released into the circulation after ingestion of a meal, a response that is markedly enhanced in patients with malabsorption. The enhanced release of peptide YY slows gastric emptying and transit of meals through the small intestine. The net effect is increased efficiency of digestion and absorption of nutrients. Once the efficiency of nutrient utilization is optimized and the delivery of unabsorbed nutrients to the distal gut decreased, peptide YY release is inhibited. As peptide YY slows colonic transit, it could also improve salvage of unabsorbed nutrients by enhancing bacterial production of volatile fatty acids and their subsequent absorption by the colonic mucosa.
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PMID:Role of peptide YY in the endocrine control of digestion. 834 32

Several problems are associated with gastric resection, including the dumping syndrome, reflux esophagitis, and malabsorption. A better understanding of the pathophysiological changes will shed light on new and improved therapy. Serum levels of seven circulating gastrointestinal hormones following a standardized solid meal and a brief score of symptoms were evaluated in 10 patients after partial distal gastrectomy and 12 patients after total gastrectomy, both groups reconstructed by Billroth II anastomosis, and 9 age-matched healthy controls. Patients underwent resection for gastric cancer and were studied 45 +/- 10 months after surgery. At the time of study, the patients had adapted well to surgery and no longer exhibited the severe symptoms of dumping seen immediately post-operatively. In contrast, the total gastrectomy patients exhibited the symptoms of reflux esophagitis. The gastrointestinal hormone changes could be divided into three patterns; obtunded responses (gastrin, PP), normal release (motilin, GIP) and increased secretion (CCK, neurotensin, PYY). In these, the early reaction of neurotensin correlated with the scores of late dumping syndrome and reflux esophagitis. In the literature, many gastrointestinal hormones have been shown to respond as an enhancement rather than adaptation. In other gastrointestinal hormones, secretin belonged to the obtunded type and enteroglucagon were classified in the increased type. However, pathophysiological significance of these hormonal changes remained uncertain. The late adaptive changes in gastrointestinal hormone secretion may help to compensate for loss of gastric motor function which accompanies gastric resection. On the other hand, these hormonal changes may exacerbate the esophageal reflux following gastrectomy.
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PMID:Gastrointestinal hormone in dumping syndrome and reflux esophagitis after gastric surgery. 940 15

Amylase inhibition has gastrointestinal and metabolic effects that may aid in the treatment of diabetes and obesity. We tested whether 4 g of a commercially available wheat amylase inhibitor (WAI) affected postprandial carbohydrate (CHO) absorption and plasma glucose or hormones. Twelve persons (four lean and four obese nondiabetics and four obese type II diabetics) were studied on 2 separate days. After eating a weight maintenance diet (55% CHO, 20% protein, and 25% fat, as percentage of calories) for 3 days, subjects ate a breakfast containing 650 kcal, the same proportion of nutrients as calories, and in random order, either WAI or no WAI. Breath H2 and plasma glucose and hormones were measured every 15 and 30 min, respectively, for 7 h. WAI decreased the delta peak postprandial plasma glucose concentrations in 10 of 12 subjects (p < 0.05) and increased the breath H2 levels in 11 (p = 0.02); the increases in breath H2 were small, generally <20 ppm. No subject experienced a change in stools, diarrhea, or bloating. In response to WAI, gastric inhibitory peptide decreased (p < 0.05), peptide YY increased (p < 0.05), and there was a trend toward increased human pancreatic polypeptide (p = 0.07). Although WAI delays CHO absorption and reduces peak postprandial plasma glucose concentrations, overall CHO malabsorption is minimal (as reflected by breath hydrogen and hormones) and without symptoms. It, therefore, may be useful in treating type II diabetes mellitus.
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PMID:Acute postprandial gastrointestinal and metabolic effects of wheat amylase inhibitor (WAI) in normal, obese, and diabetic humans. 970 Sep 50

Exposure of the ileum to nutrients markedly inhibits several upper gastrointestinal functions. Hormonal peptides of the ileal wall, i.e. peptide YY (PYY), glucagon-like peptide-1 (GLP-1), and neurotensin (NT), are thought to play a role in this negative feedback mechanism. The present study was conducted to comparatively assess the secretion of PYY, GLP-1, and NT upon luminal infusion of a variety of individual luminal factors in the isolated vascularly perfused rat ileum preparation. PYY, GLP-1, and NT were measured in the portal effluent with specific RIAs. Glucose (250 mM) induced a pronounced release of the three peptides, whereas a physiological concentration of 5 mM did not induce peptide secretion. Peptone (5%, wt/vol) evoked a sustained release of PYY, GLP-1, and NT. Only NT secretion was increased upon luminal administration of 100 mM sodium oleate. Short chain fatty acids (20 mM) evoked an early and transient release of the three peptides. In contrast, taurocholate (20 mM) induced a sustained release of PYY, GLP-1, and NT, but the threshold concentration for peptide release was lower for NT than for PYY or GLP-1. Cellulose or pectin (0.5%, wt/vol) did not modify peptide secretion. In conclusion, glucose and peptone are potent stimulants of PYY, GLP-1, and NT release. Only NT is released upon oleic acid stimulation. Finally, taurocholate is a potent stimulant of the release of the three peptides. Overall, PYY, GLP-1, and NT may participate cooperatively in the ileal brake. As relatively high concentrations of the various stimulants were required to elicit peptide release, it seems likely that this mechanism operates in cases of maldigestion or malabsorption.
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PMID:Peptide YY, glucagon-like peptide-1, and neurotensin responses to luminal factors in the isolated vascularly perfused rat ileum. 972 30

Effective clinical therapy to augment intestinal absorption of water and electrolytes does not exist; the gut hormone, peptide YY (PYY), is a potent proabsorptive agent in animal models. The purpose of our study was to evaluate the effects of two novel PYY analogs, BIM-43073D and BIM-43004C, on intestinal absorption. Dogs with ileal Thiry-Vella fistulae (TVF) were treated with either PYY, BIM-43073D, or BIM-43004C. Administration of BIM-43073D significantly increased water and sodium absorption over baseline and maintained this level of increased absorption for a longer duration than an equimolar dose of PYY. Administration of BIM-43004C significantly increased sodium and water absorption over baseline at a level equal to that of PYY. The novel PYY analogs, BIM-43073D and BIM-43004C, are effective proabsorptive agents with BIM-43073D producing more sustained effects than PYY. These compounds may be clinically useful in the treatment of gut malabsorption in conditions such as cholera, Crohn's disease, and the short-bowel syndrome.
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PMID:Characterization of two novel proabsorptive peptide YY analogs, BIM-43073D and BIM-43004C. 1008 Jan 63


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