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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The insulinogenic factor of the gastrointestinal mucosa named "incretin" is only one part of the complex enteroinsular axis. --2. Of the chemically defined gastrointestinal hormones GIP is the strongest incretin candidate. --3. Because of the dual function of GIP as gastrone and insulinotropic substance several safeguards against GIP-mediated insulin hypoglycaemia exist. --4. No pathological condition has yet been found which is causally related to hyper- or hyposecretion of GIP. However, an exaggerated GIP response (usually secondary to the disease) may participate in the pathogenesis of hyperinsulinaemia of patients with obesity and duodenal ulcer. --5. The injection of GIP antibodies only partially abolishes the incretin effect. Therefore, GIP, although important, is not the only incretin.
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PMID:The incretin concept today. 3 19

To investigate the role of endogenous insulin on the secretion of immunoreactive gastric inhibitory polypeptide (IR-GIP) the response of IR-GIP and immunoreactive insulin (IRI) to an oral fat load (100 g triglyceride) alone and during an intravenous glucose infusion (0.7 g/kg/h) was examined in normal weight and obese subjects. In normal weight subjects the fat induced integrated rise of IR-GIP was 112.7 +/- 9.4 ng/ml/120 min. When glucose and fat were given together this IR-GIP response was lowered to 46.2 +/- 2.9 ng/ml/120 min while the serum IRI response to i.v. glucose and the glucose tolerance were enhanced by fat ingestion. In obese subjects with normal glucose tolerance the GIP suppressing effect of i.v. glucose infusion was less marked than in controls. The integrated IR-GIP response to fat ingestion was 225.6 +/- 20.3 mg/ml/120 min and to fat plus glucose 152.6 +/- 14.8 ng/ml/120 min. In obese subjects with glucose intolerance i.v. glucose completely failed to lower the exaggerated secretion of IR-GIP following oral fat. Thus, a graded abnormality of the GIP response to glucose induced insulin release occurs in obesity with normal and pathological glucose tolerance. After reducing the ideal body weight of six obese subjects with glucose intolerance by hypocaloric diet for 3 weeks the exaggerated rise of IR-GIP after oral fat was reversed and the lowering effect of i.v. glucose on the IR-GIP response re-established.
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PMID:Impaired feedback control of fat induced gastric inhibitory polypeptide (GIP) secretion by insulin in obesity and glucose intolerance. 11 43

Serum GIP, insulin, and glucose concentrations were determined during a standard oral glucose tolerance test in 80 individuals, 45 of whom were normal and 35 of whom had adult-onset diabetes mellitus according to USPHS criteria. As a group, the diabetics had fasting hyperglycemia (219 +/- 17 mg./dl.) and, in response to glucose, displayed a peak serum glucose of 373 +/- 23 mg./dl. and sustained hyperglycemia (315 +/- 24 mg./dl.) at 180 minutes. There were no statistically significant differences in absolute serum insulin levels between the two groups. However, insulin secretion was delayed, IRI increments were smaller, and the IRI concentrations were inappropriately low for the simultaneous serum glucose concentrations in the diabetics at every time interval tested. Mean fasting serum GIP was 335 +/- 30 pg./ml. in the diabetics as against 262 +/- 15 pg./ml. in normal individuals (p less than 0.025). After the ingestion of glucose, diabetics had significantly higher (p less than 0.001) mean serum GIP levels between five and 120 minutes. By 180 minutes, serum GIP levels remained above fasting in both groups, but the diabetics had higher than normal serum concentrations (p less than 0.05). Peak serum GIP concentrations, which occurred at 30 minutes in both groups, were 1,376 +/- 106 and 806 +/- 75 pg./ml. in the diabetics and normals, respectively (p less than 0.001). Total integrated serum GIP was also greater in diabetics than normals (140,852 +/- 14,208 vs. 64,602 +/- 8,719 pg.-min./ml.-1, p less than 0.001). The higher serum GIP concentrations observed following glucose ingestion in diabetics could not be attributed to obesity or age. We conclude that both fasting and glucose-stimulated GIP concentrations are higher than normal in obese adult-onset diabetics. The significance of this observation is uncertain. However, since our current understanding suggests the GIP may be an important enteric signal for the release of insulin in man, and because GIP has been shown to stimulate the release of immunoreactive glucagon, GIP may play a role in the pathogenesis of diabetes mellitus.
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PMID:Gastric inhibitory polypeptide (GIP) in maturity-onset diabetes mellitus. 97 1

The response of immunoreactive gastric inhibitory polypeptide (IR-GIP), immunoreactive insulin (IRI) and immunoreactive C-peptide (IR-C-peptide) to the ingestion of mixed liquid test meals containing 1031 kcal (550 ml) and 422 kcal was studied in 17 obese and 17 normal weight control subjects. When the 422 kcal load was ingested in a volume of 550 ml, the plasma IR-GIP response was significantly greater than in a volume of 225 ml at 15 and 30 min in lean and obese subjects, but the total integrated IR-GIP response was not significantly different between the obese and lean group. Also intraduodenal infusion of 150 ml (280 kcal) of the test meal elicited identical plasma IR-GIP concentrations in lean and obese subjects. An exaggerated IR-GIP response in obese subjects was seen only following the 1031 kcal load (integrated IR-GIP response: 23.6 +/- 1.9 in lean subjects vs 50.3 +/- 3.8 nmol/l/180 min in obese subjects; p less than 0.01). The IRI response was always significantly greater in obese than in lean subjects and not related to the GIP response. Fasting plasma IR-C-peptide levels were significantly elevated in obese subjects (lean: 0.52 +/- 0.04; obese: 1.42 +/- 0.12 nmol/l; p less than 0.005), but the postprandial integrated IR-C-peptide responses in the obese and lean group were identical, indicating decreased hepatic insulin extraction in obesity. It is concluded that an exaggerated IR-GIP response in obesity occurs only after ingestion of a high calorie meal probably as consequence of an increased gastric emptying rate and that the hyperinsulinemic response of obese subjects is not attributable to GIP hypersecretion.
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PMID:Gastric inhibitory polypeptide (GIP) hypersecretion in obesity depends on meal size and is not related to hyperinsulinemia. 266 6

Obesity is characterised by fasting and post-prandial hyperinsulinaemia. One factor which may contribute to this is overactivity of the enteroinsular axis. Glucose tolerance, beta-cell response and GIP profiles were therefore compared during oral glucose (OGTT), mixed meal (MTT) and intravenous glucose tolerance tests (IVGTT) in both lean (IBW less than 120%) and obese (IBW greater than 120%) healthy subjects. The tests were repeated in the obese group after a period of dietary restriction and weight loss. Fasting GIP concentrations were similar, but postprandial levels were significantly greater in the obese subjects during both the OGTT and MTT. Glucose profiles were similar but associated with basal and stimulated hyperinsulinaemia in the obese subjects indicating insulin resistance. GIP levels did not change during the IVGTT and were similar in the two groups throughout the test. Following diet and weight-reduction there was a significant decrease in both fasting and post-prandial insulin levels in the obese subjects but there were no significant changes in glucose or GIP concentrations. In conclusion the endogenously stimulated plasma GIP response is exaggerated in obese healthy subjects but this increased response is not decreased by short term diet and weight loss. The increased GIP concentrations may contribute the observed hyperinsulinaemia in obesity, but its contribution is likely to be small in view of the decrease in insulin concentrations following diet and weight-loss which was independent of any change in GIP.
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PMID:Obesity is associated with increased post-prandial GIP levels which are not reduced by dietary restriction and weight loss. 272 10

Epidemiologic evidence favors the hypothesis that obesity may result from the fiber-depleted diet of industrialized societies. Since hyperinsulinemia is a universal characteristic and perhaps causal of obesity, the possibility is considered that dietary factors causing excess insulin secretion might lead to obesity. Dietary glucose causes a slightly greater insulin rise than cooked starch containing an equal amount of carbohydrate, and high fiber starchy foods cause a much lesser insulin response than does glucose in solution. Doubling the dose of carbohydrate in a meal causes only a small increase in glucose response but a large increase in insulin response. Dietary fiber could act by displacing some of the carbohydrate that would normally be absorbable in the small intestine, or could translocate the carbohydrate to a point lower in the intestinal tract where less effect on insulin secretion would be observed. Evidence is presented that a higher fiber diet is associated with a higher concentration of fasting circulating free fatty acids, a lesser post-cibal decrease in circulating free fatty acids and triglycerides and less chronic increase in fasting triglycerides than a low fiber diet. These differences are associated with a lesser insulin response to high fiber meals. The extreme fluctuations between the fed and fasted states seen with low fiber diets are thus dampened by high fiber diets. The less complete inhibition of lipolysis during the fed state, and more intense lipolysis during fasting, suggested by the above data, might tend to prevent obesity. The mechanisms of the lesser insulin response to high rather than low fiber meals are not known, but the possibility that dietary fiber decreases the GIP response is considered.
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PMID:The effect of dietary fiber and other factors on insulin response: role in obesity. 299 35

The effect of cholinomimetic stimulation by infusion of edrophonium chloride or muscarinic blockade by infusion of atropine sulfate on insulin and GIP secretion was studied in normal lean subjects during eu- and hyperglycemia. Cholinomimetic stimulation led to a slight non-significant increase and muscarinic blockade to a slight, non-significant suppression of both GIP and insulin. No modification of the insulin secretion pattern was observed under either condition during hyperglycemia. The effect of atropine infusion on fasting plasma insulin and GIP was subsequently studied in 11 obese patients and 10 lean subjects. Muscarinic antagonism by atropine led to a transient non-significant suppression of GIP and insulin in lean subjects, but to a significant, sustained suppression of these hormones in obese patients. Insulin and GIP levels were however, not suppressed to control values after atropine administration in obese patients. A positive correlation was found between fasting plasma insulin and maximal suppression of insulin attained during the 30 min following administration of atropine. It is concluded that part of the hyperinsulinemia observed in human obesity is under the control of the parasympathetic nervous system. An abnormal balance between sympathetic inhibitory and parasympathetic stimulatory tones on insulin secretion, as observed in the VMH lesioned rat, might be present in human obesity.
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PMID:Effects of cholinergic stimulation and antagonism on plasma insulin concentration in lean and obese human subjects. 354 47

Food can affect the production and secretion of hormones by direct actions on the gut, by nervous reflexes, through changes in the concentration of various metabolites in the blood, or secondary to changes in circulating gut hormone levels. Not only is the composition of the diet important but also its texture, quantity and duration. GIP and insulin are used as examples of hormones whose production and secretion are diet-dependent. Their possible involvement in the pathogenesis of obesity and non-insulin-dependent (type II) diabetes is discussed.
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PMID:How our food affects our hormones. 388 42

The available data show that GIP is at present the strongest candidate for the insulin-secreting factor of the gut named incretin. Its release is triggered by the absorption of ingested nutrients. GIP acts on the B-cells of the pancreas by potentiating glucose-induced insulin secretion. The role of GIP as an enterogastrone is less well established. The release of GIP from the gut cells seems to be regulated by the composition and the amount of the ingested food, by the rate of absorption of nutrients by neural factors (vagal), and by feedback control mediated by insulin. In addition, the adaptation of the intestine to individual eating habits influences the response of the GIP cells. It is suggested that an overactive enteroinsular axis, i.e. enhanced GIP secretion, participates in the development of the hyperinsulinaemia of obesity and maturity onset diabetes mellitus. In gastrointestinal diseases accompanied by malabsorption the GIP response is diminished. In gastrointestinal disorders with rapid gastric emptying (duodenal ulcer) or with accelerated passage of the nutrients through the intestine, hypersecretion of GIP and insulin occurs. This may be significant for the reactive hypoglycaemia of these conditions.
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PMID:Gastric inhibitory polypeptide. 610 91

The role of GIP in the pathogenesis of spontaneous syndromes of obesity-diabetes was examined in ob/ob mice of the Aston stock and db/db mice of the C57BL/KsJ background. Compared with lean controls, fed adult ob/ob and db/db mice, respectively, exhibited 1.8-fold and 2.1-fold increases in body weight, 1.8-fold and 2.8-fold elevations of plasma glucose, and 15.4-fold and 5.6-fold elevations of plasma insulin. As indicated by the relative magnitude of the hyperglycemia and hyperinsulinemia, db/db mice displayed a particularly severe form of diabetes. Plasma GIP concentrations of ob/ob and db/db mice were elevated 15.1-fold and 6.2-fold, respectively; the increments closely corresponded with the degrees of hyperinsulinemia. Small intestinal weight was increased 1.4-fold and 1.8-fold in ob/ob and db/db mice, respectively, but the intestinal GIP content expressed as microgram/g intestine or microgram/intestine was raised only in ob/ob mice (1.9-fold and 2.8-fold, respectively). Since glucose stimulation of insulin release is defective in both mutant strains, the results strongly implicate pathologically raised GIP concentrations in the hyperinsulinemia and related metabolic abnormalities of the obesity-diabetes syndromes. It is suggested that hypersecretion of GIP results in part from loss of normal feedback inhibition by endogenous insulin.
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PMID:Abnormalities of GIP in spontaneous syndromes of obesity and diabetes in mice. 634 Nov 26


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