Natural purified porcine gastric inhibitory polypeptide (GIP) stimulates exocrine pancreas secretion due to contamination with a cholecystokinin-like substance

Mueller, Michael K.; Demol, P.; Goebell, H.; Fladrich, G.; Brown, John C.

doi:10.1016/0167-0115(83)90288-4

Cited by 8 publications

(5 citation statements)

References 21 publications

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“…Recently, synthetic porcine and human GIP have been made available. Two studies (5,6) have been reported about stimulation of exocrine pancreatic secretion by GIP, but the effect was subsequently identified by the authors to be due to contamination with CCK-like peptides.…”

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confidence: 93%

Commercially Available Preparations of Porcine Glucose-Dependent Insulinotropic Polypeptide (Gip) Contain a Biologically Inactive Gip-Fragment and Cholecystokinin-33/-39

Kümmel

et al. 1987

Endocrinology

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Commercially available preparations of natural porcine glucose-dependent insulinotropic polypeptide (GIP) were subjected to reverse phase HPLC. The material was found to give rise to 4 peaks which were characterized by HPLC-retention time and N-terminal sequence analysis. They represented: intact porcine GIP(1-42), 58% (wt/wt); the GIP-fragment des-tyr-ala-GIP(3-42), 32% (wt/wt); cholecystokinin (CCK)-33 2% (wt/wt); CCK-39 2% (wt/wt). HPLC-pure GIP(1-42) stimulated insulin release in rat isolated pre-cultured pancreatic islets in the presence of 16.7 mM glucose up to 240% vs. control, whereas the fragment des-tyr-ala-GIP(3-42) did neither increase insulin release nor exhibit antagonistic activity to GIP(1-42) at 100 ng/ml. These results indicate that commercially available porcine GIP-preparations may contain the biologically inactive des-tyr-ala-GIP(3-42) in high amounts, and in addition may be contaminated by CCK-peptides. HPLC-characterization of these peptide preparations prior to any biological study is crucial.

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confidence: 93%

Commercially Available Preparations of Porcine Glucose-Dependent Insulinotropic Polypeptide (Gip) Contain a Biologically Inactive Gip-Fragment and Cholecystokinin-33/-39

Kümmel

et al. 1987

Endocrinology

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“…The absence of effects of a synthetic preparation of GIP on calcium efflux, accumulation of cyclic GMP and release of amylase suggests that such effects of natural GIP were due to contaminants. The recent reports by Jensen et al (1982) and Mueller et al (1983) indicates that purified natural GIP is contaminated by CCK. Gardner & Jackson (1977) have suggested that there are two pathways for stimulation of enzyme secretion from the pancreas: one is activated by cholecystokinin as well as cholinergic agents and the other by secretin and VIP.…”

Section: Discussionmentioning

confidence: 99%

“…We have earlier reported (Sjodin & Conlon 1980) that a highly purified preparation of natural GIP stimulates outflux of calcium, increases intracellular accumulation of cyclic nucleotides and releases amylase from isolated pancreatic acinar cells. Since some of these effects may have been due to contaminants of the GIP preparation (Sjodin & Conlon 1980) and a low degree of contamination of the preparation of natural GIP has recently been described (Jensen et al 1982, Mueller et al 1983 we have compared the effects of purified natural GIP with those of synthetic GIP. The results show that the cholecystokinin-like effects on pancreatic acinar cells of a preparation of natural GIP probably are due to a minor contamination with CCK while a moderate stimulating effect on cyclic AMP accumulation in acinar cells is at least partly due to GIP itself.…”

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confidence: 99%

Effects of gastric inhibitory polypeptide on dispersed pancreatic acinar cells from the guinea pig

Sjödin

Conlon

1984

Acta Physiologica Scandinavica

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Purified natural porcine gastric inhibitory polypeptide (GIP), in high concentrations, was found to stimulate outflow of 45Ca, increase cellular accumulation of cyclic GMP and cyclic AMP and cause release of amylase from dispersed pancreatic acinar cells. Synthetic GIP increased cellular cyclic AMP levels, but did not affect outflux of calcium, cellular levels of cyclic GMP or release of amylase. The discrepancy between results with natural and synthetic preparations of porcine GIP may be explained by a possible contamination of natural GIP with cholecystokinin. Other examined pancreatic secretory stimulating peptides which induce cyclic AMP accumulation in acinar cells, also increase release of amylase. Synthetic GIP increased levels of cyclic AMP without affecting amylase release. This suggests that the correlation between amylase release and total cellular accumulation of cyclic AMP in response to GIP is not close.

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“…GIP is known to be strongly insulino tropic in the presence of glucose, but it has no effect by itself on the secretion of the exocrine pancreas after a contaminant is removed by further high-pressure liquid chromatography purification [16]. This is again confirmed here as shown in figures 1 and 2 where GIP has neither an effect on insulin release in the presence of 2.8 X 10-3 M glucose nor on the exocrine pancreas, but a strong insulinotropic action in the presence of 15.8 X 10~3 M glu cose.…”

Section: Discussionmentioning

confidence: 99%

“…20], GIP has no effect on the exocrine pancreas, but is strongly insulinotropic in the presence of glucose [15,16], Insulin as well has no effect on the exocrine pancreas by itself [34], Although sympathetic and para sympathetic agents have been reported to modulate the release of GIP from the small intestine [1,17], it is not known how they interact with the action of GIP on pancreatic endocrine secretion.…”

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confidence: 99%

Interaction of Acetylcholine and Gastric Inhibitory Polypeptide on Endocrine and Exocrine Rat Pancreatic Secretion: Augmentation of Acetylcholine-Induced Amylase and Volume Secretion by the Insulinotropic Action of Gastric Inhibitory Polypeptide

et al. 1986

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Exocrine pancreatic secretion is under partial control of endocrine pancreatic hormones. We studied the interaction of three doses of acetylcholine (Ach), a stimulator of exocrine and endocrine pancreatic secretion, with one dose of gastric inhibitory polypeptide (GIP) which is strongly insulinotropic, but has no effect on exocrine pancreatic secretion. The effects of Ach and GIP on insulin secretion from the rat pancreas were additive at 0.05 × 10^-6M Ach and slightly, but not significantly less than additive at 0.25 or 2.5 × 10^-6M Ach. GIP had an augmenting effect on amylase and volume secretion from the pancreas, when pancreatic secretion was stimulated by 2.5 × 10^-6M Ach, but not by 0.05 or 0.25 × 10^-6M. Exogenous rat insulin could exert an effect similar to that of GIP, although a higher dose was required. Atropine inhibited the effect of Ach on exocrine and endocrine pancreatic secretion, but not the insulinotropic action of GIP. It is hypothesized that GIP could play a role in regulating exocrine pancreatic secretion by its insulinotropic action.

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Natural purified porcine gastric inhibitory polypeptide (GIP) stimulates exocrine pancreas secretion due to contamination with a cholecystokinin-like substance

Cited by 8 publications

References 21 publications

Commercially Available Preparations of Porcine Glucose-Dependent Insulinotropic Polypeptide (Gip) Contain a Biologically Inactive Gip-Fragment and Cholecystokinin-33/-39

Commercially Available Preparations of Porcine Glucose-Dependent Insulinotropic Polypeptide (Gip) Contain a Biologically Inactive Gip-Fragment and Cholecystokinin-33/-39

Effects of gastric inhibitory polypeptide on dispersed pancreatic acinar cells from the guinea pig

Interaction of Acetylcholine and Gastric Inhibitory Polypeptide on Endocrine and Exocrine Rat Pancreatic Secretion: Augmentation of Acetylcholine-Induced Amylase and Volume Secretion by the Insulinotropic Action of Gastric Inhibitory Polypeptide

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