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Query: UNIPROT:P01350 (gastrin)
 9,683 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gastrointestinal anatomy and function has been studied prospectively in 12 patients undergoing jejunoileal bypass surgery in order to investigate the adaptive response of the intestinal mucosa. The total thickness of the jejunal mucosa did not change after surgery, but the crypts became relatively deeper, suggesting a more rapid turnover of gastrointestinal cells. The absorption of oxalate was depressed in the immediate postoperative period but had improved toward preoperative levels by 6 months. Vitamin B12 absorption also declined postoperatively, and increased thereafter in the patients with an end-to-end jejunoileostomy, but showed a much smaller recovery in the group with an end-to-side anastomosis. The cholesterol concentration (lithogenicity) of the duodenal bile rose by 30% in the first 3 weeks after surgery, but had returned to preoperative levels by 6 months. The segmental absorption of glucose across the jejunum declined after surgery. Caloric intake also declined, whether measured as the quantity of food that patients elected to eat over a 24-hr period, or as the quantity of a liquid lunch which they consumed over a 20-min period. The level of basal gastric acid was increased postoperatively but the maximal output after histamine stimulation was not. The gastrin response to a standard liquid meal was also significantly increased after surgery. Enteroglucagon secretion showed an increase in 3 weeks and a further increase by 6 months after intestinal bypass surgery. The significance of these changes to intestinal adaptations is discussed.
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PMID:Intestinal adaptation after jejunoileal bypass in man. 83 37

The effect of intravenous glucagon infusion on serum levels of immunoreactive GIP (IR-GIP), insulin (IRI), gastrin (IRG), and on blood glucose has been investigated in six healthy volunteers in the fasting state and during ingestion of a mixed standard meal. Glucagon (500 ng/kg/min) lowered significantly serum levels of IR-GIP and IRG below the fasting values and increased the levels of IRI and blood glucose. Glucagon (50 ng/kg/min) infused 30 minutes before and continued 90 minutes after ingestion of a test meal abolished the IR-GIP response, suppressed significantly the IRG response, and left the IRI response unchanged. The same glucagon dose infused 60 minutes after ingestion of the test meal decreased significantly the raised levels of IR-GIP and IRG to fasting levels without changing IRI values. It is concluded that exogenous glucagon inhibits Gip release at the level of the GIP-producing cells.
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PMID:Lowering of fasting and food stimulated serum immunoreactive gastric inhibitory polypeptide (GIP) by glucagon. 85 72

In addition to established gastrointestinal hormones--secretin, cholecystokinin-pancreozymin (CCK-PZ), gastrin, and glucagon---some 30 polypeptides with gastrointestinal actions can be listed. New aspects of these substances include the following: Gastrin and vasoactive intestinal peptide (VIP) can be also encountered in the central nervous system and may act as transmitters. CCK-PZ-serum concentrations are found markedly elevated in patients with exocrine pancreatic insufficiency; this may provide the opportunity to establish a realtively simple screening test. Moreover, there is evidence that serum-CCK-PZ levels serve as satiety signal. Secretin secretion is said to be enhanced in hunger and then to act as a lipolytic hormone. In addition to enteroglucagon, a gastrintestinal peptide identical to pancreatic glucagon has been detected. Gastric inhibitory polypeptide (GIP) inhibits gastric secretion and motility (enterogastrone activity) and together with glucose it stimulates insulin release (incretin activity). Motilin increases lower esophageal sphincter pressure, enhances gastric pepsin secretion and slows down gastric evacuation. Serum levels of pancreatic polypeptide may be found elevated as a diagnostic index in patients with endocrine peptide tumors of the pancreas. Recently, the potential importance of local (paracrine) actions of gastrointestinal polypeptides has been amphasized. Predominantly paracrine activity is exhibited by some prototype hormones, e.g. somatostatin, substance P, bombesian, and the non-polypeptide compounds, prostaglandins.
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PMID:[New views on gastrointestinal hormones]. 85 99

The hormonal and metabolic response to the first feed of breast milk was studied in 12 infants at 4-6 hours of age. After the feed there was an increase in blood glucose concentration but no changes in the concentrations of lactate, pyruvate, alanine, or ketone bodies. The feed was followed by an increase in the concentrations of plasma insulin, growth hormone, gastrin, and enteroglucagon, but no change in levels of plasma glucagon or gastric inhibitory peptide. Several hormone systems are functionally active at birth and are stimulated by the first feed of milk.
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PMID:Endocrine and metabolic response in the human newborn to first feed of breast milk. 86 Aug 74

The anaesthetised rat stomach preparation was adapted to assay intraluminally administered stimulants and inhibitors of acid secretion by continuously recirculating the perfusate (15 ml of 5% glucose) and measuring acid by the pH-stat technique. The responses obtained were linear. Continuous artificial neutralisation of the stomach to pH 5.5 as well as variation of the pH between 6.5 and 4.0 did not significantly alter the sensitivity of the preparation to intravenously administered human gastrin-heptadecapeptide I (HG I). Basal acid secretion however significantly declined following stepwise lowering of the intragastric pH between 6.5 and 4.0. The threshold values for responses to i.v. HG I were below 16 ng. 6 doses could be given per rat without tachyphylaxis. Acetylcholine, 1.3, 2.5, 5.2 and 10.4 micron g/ml in the perfusate, induced a dose-dependent linear (r=0.902) acid secretion. Metiamide 1.66 mg/ml in the perfusate, produced a parallel shift to the right of the HG I dose--response curve producing an agonist dose ratio of 3.66. The data suggest that intragastrically applied stimulants and inhibitors of acid secretion can be studied precisely in this relatively simple preparation.
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PMID:Intragastric titration of acid in the perfused rat stomach preparation following parenteral and intraluminal stimulation. 87 79

In an attempt to elucidate the mechanism of action of phenformin, eleven juvenile-onset, insulin-requiring diabetic subjects underwent four different treatment regimens during standard breakfast tests. These four treatments were: control (no insulin or phenformin); insulin alone (15 U regular insulin administered subcutaneously one-half hour before breakfast); phenformin alone (50 mg of the timed-release capsule given twice daily for three days before the study and two and one-half hours before breakfast on the day of study); and phenformin plus insulin (in the amounts and at the times stated above). Phenformin was found to decrease postprandial hyperglycaemia significantly when compared with control values, and its addition to insulin further decreased the postprandial glucose rise below that found with insulin alone (p less than 0.005). These effects were associated with a reduction in early (30-min) postprandial hyperglucagonaemia (p less than 0.05). Triglyceride levels, gastrin secretion, growth hormone levels, and increments of alpha-amino nitrogen were not affected by phenformin. Thls, suppression of postprandial hyperglucagonaemia may be an additional mechanism in the reduction of postprandial hyperglycaemia after phenformin.
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PMID:Plasma glucagon suppression by phenformin in man. 90 74

When isolated rat liver cells were incubated for 15 min in the presence of vasoactive intestinal peptide, secretin, gastrin, caerulein or glucagon at concentrations ranging from 0.2 microgram to 2 microgram per ml, glycogenolysis was stimulated. Among the gastrointestinal hormones or peptides tested, vasoactive intestinal peptide had the highest stimulatory activity. However, somatostatin was inhibitory for liver glycogenolysis. Combination experiments showed that somatostatin also inhibited the stimulatory effects of vasoactive intestinal peptide and secretin, but not that of glucagon, while glucagon and vasoactive intestinal peptide, or glucagon and secretin showed additive effects on glycogenolysis, but secretin and vasoactive intestinal peptide did not. The results suffest that the receptor site of glucagon is different from those of secretin and vasoactive intestinal peptide. Slight but significant stimulation of gluconeogenesis was also observed by vasoactive intestinal peptide and secretin. The evidence presented in this paper indicates that the so-called enterohepatic axis, in which a part of serum glucose levels is regulated directly by gastrointestinal hormones, exists and that the axis is inhibited by somatostatin.
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PMID:Effects of gastrointestinal and related hormones on glycogenolysis and gluconeogenesis in cultured liver cells. 92 81

In 16 experiments on 4 healthy subjects, the effect of procedures which alter blood glucose, ie, infusion of 0.2 units/kg body wt/hr insulin and/or 0.66 g/kg body wt/hr glucose, on gastric acid secretion, plasma gastrin, and plasma osmolality was studied, Each subject underwent four different experimental procedures, each lasting 4 hr. All had in common one basal hour and the infusion of insulin in the second hour, but differed in the time of infusion of glucose or isotonic saline. To control for order effects, the four procedures were applied to the subjects in the form of a Latin square. Acid output was measured continuously be means of intragastric titration and a telemetering capsule; blood glucose, plasma gastrin, and plasma osmolaity were determined in 15-min intervals. An inverse relationship between blood glucose and acid output was found: Low glucose levels were associated with high rates of acid secretion, high glucose levels with low acid secretion. No noticeable changes occurred in either plasma gastrin or plasma osmolality. These results reveal a determining influence of blood glucose levels on acid secretion. On the basis of earlier work in animals it is concluded that this influence is exerted via the reciprocal activities of the hypothalamic satiety and feeding centers.
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PMID:Effect of alterations of blood glucose levels on gastric acid secretion, plasma gastrin, and plasma osmolality in man. 94 97

The response of serum immunoreactive gastric inhibitory polypeptide (IR-GIP), gastrin (IRG) and insulin (IRI) to a mixed standard meal was measured in 15 controls, 6 patients with coeliac disease, 26 patients with chronic pancreatitis and partial duodenopancreatectomy (Whipple's procedure). Serum levels of IR-GIP, IRG and IRI were significantly reduced in patients with coeliac disease. The serum glucose increase was significantly smaller only during the first hour after the meal. Since small intestinal GIP- and G-cells are situated mainly in the glands of duodenal and jejunal mucosa their absolute number is not significantly reduced in coeliac disease. It is suggested that the release of IR-GIP and duodenal IRG is influenced by the rate of absorption of nutrients. In patients with chronic pancreatitis the IR-GIP release is significantly greater than in controls, the IRG release normal and the IRI response delayed. After Whipple's procedure the IR-GIP response is increased significantly while the IRG secretion is abolished. This demonstrates that the duodenum is not necessary for GIP release and that pancreatic and jejunal gastrin are without clinical significance.
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PMID:Gastric inhibitory polypeptide (GIP), gastrin and insulin: response to test meal in coeliac disease and after duodeno-pancreatectomy. 95 38

Liquid test meals were infused into the stomach and acid secretion was measured by intragastric titration at pH 5.0 Acid secretion after 500 or 750-ml sodium chloride meals was two to three times higher than basal secretion rates and was equivalent to 25-30% of the peak acid output in response to histamine. Since these meals did not cause a rise in serum gastrin concentration, it is assumed that they stimulate acid secretion by causing distention of the body and fundus of the stomach. Compared with this distention stimulus, glucose meals had no effect on acid secretion and fat-inhibited acid secretion; however, both glucose and fat caused an increase in serum gastrin concentration. Amino acids caused a much greater increase in serum gastrin concentration and enhanced acid secretion above that noted with distention alone. In contrast, albumin did not enhance the serum gastrin concentration or stimulate acid secretion to a statistically significant extent. There was a close correlation between the rise in serum gastrin concentration and rate of acid secretion after different test meals when average results for each test meal were plotted. However, there was a poor correlation between acid secretion and serum gastrin concentration when the responses of the individual subjects with a given test meal were compared. Our interpretations are: (a) Distention is an important stimulant of the acid-secretory response to a meal, and this is not mediated by gastrin release. (b) Gastrin is one but probably not the only mediator of the chemical phase of acid secretion, i.e., acid secretion noted with amino acids that cannot be explained by distention. (c) Glucose and fat also release gastrin; however, with glucose the rise in serum gastrin is too small and too transient to enhance acid secretion, and fat probably releases unmeasured inhibitors that overwhelm the effect of gastrin on acid secretion. (d) Albumin is not a stimulant of acid secretion.
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PMID:Studies on the mechanisms of food-stimulated gastric acid secretion in normal human subjects. 95 91


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