Effect of Bombesin on Glucose-Induced Insulin Release in Humans

Scarpignato, Carmelo; Gioffré, Mara; Micali, B

doi:10.1159/000199477

Cited by 4 publications

(5 citation statements)

References 26 publications

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“…In our experimental conditions, a 15min bombesin infusion had no effect on basal levels of insulin and glucose, in agreement with previous reports (Scarpignato & Micali, 1986;Scarpignato et al, 1987b). Although no effect on basal insulin levels was observed after bombesin administration, a clear-cut enhancement of insulin release was evident when glucose was injected intravenously.…”

Section: Discussionsupporting

confidence: 93%

“…Plasma glucose and insulin after the intravenous glucose load (20g) during bombesin or saline infusion are depicted in Figure 2. As previously described (Scarpignato & Micali, 1986;Scarpignato et al, 1987b), bombesin did not affect basal levels of both parameters. It was, however, able to increase I significantly the insulinogenic power of glucose.…”

Section: Intravenous Glucose Loadsupporting

confidence: 71%

“…In previous papers, we have shown that bombesin affects the insulin response to mixed meal (Scarpignato & Micali, 1986) and to oral as well as intravenous glucose load (Scarpignato et al, 1987b). However, no effect on basal insulin levels was observed.…”

Section: Introductionmentioning

confidence: 92%

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Different effects of bombesin on glucose‐ and tolbutamide‐induced insulin release in man

Scarpignato

Gioffré

Gulino

et al. 1988

British J Pharmacology

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The effect of bombesin, a neurograstrointestinal peptide, on basal and stimulated insulin release was studied in man. Two different stimuli were used, hyperglycaemic (20 g glucose) and hypoglycaemic (1 g tolbutamide). They were injected intravenously to two groups of male healthy volunteers during saline or bombesin (5 ng kg−1 min−1 for 60 min) infusion. The peptide had no significant effect on basal levels of glucose and insulin. However, the insulin response to intravenous glucose was strongly potentiated by bombesin, the integrated insulin response being 2.23 ± 0.59 mu ml−1 · 90 min and 0.98 ± 0.19 mu ml−1 · 90 min during infusion of bombesin and saline, respectively (P < 0.05). The behaviour of plasma glucose was not significantly modified by the peptide. Indeed, the glucose disappearance rate (K of Conard, mg min 10−2) changed from 2.5 ± 0.3 during saline to 2.4 ± 0.4 during bombesin infusion. When the hypoglycaemic stimulus (i.e. tolbutamide) was used, no effect of the peptide on insulin release could be detected. Here again, the drop in plasma glucose (expressed as Marigo's coefficient) was not affected by the peptide, with a value of 92.8 ± 12.6 and 84.0 ± 10.9 during bombesin and saline administration. These data therefore show that, at normal or low blood glucose levels, the dose of bombesin used is unable to modify insulin release and suggest that this peptide might be regarded as a glucose‐dependent insulinotropic peptide.

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Section: Discussionsupporting

confidence: 93%

Section: Intravenous Glucose Loadsupporting

confidence: 71%

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Different effects of bombesin on glucose‐ and tolbutamide‐induced insulin release in man

Scarpignato

Gioffré

Gulino

et al. 1988

British J Pharmacology

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“…As a matter of fact, bombesin was found to increase the release of pancreatic hormones (insulin, glucagon and pancreatic polypeptide) in several animal species, in cluding man [25]. Exocrine pancreatic func tion was affected by bombesin as well.…”

Section: Introductionmentioning

confidence: 98%

Effect of Bombesin and Its Mammalian Counterpart, GRP, on Exocrine Pancreas in the Rat

et al. 1988

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The effect of equimolar doses (6 nmol/kg) of bombesin and its mammalian counterpart, GRP, on pancreatic growth and secretion was studied in adult rats. Both peptides were administered intraperitoneally three times a day for 5 consecutive days. Saline-treated rats were used as controls. At the end of the treatment, animals were anaesthetized and pancreatic juice was collected in basal conditions and after caerulein (0.75 nmol/kg i.p.) stimulation. Afterwards, the rats were sacrificed and growth and composition of the pancreatic tissue were determined. Compared with the control (saline) values, either basal or stimulated secretion was significantly increased after short-term treatment with both peptides. In addition, both bombesin and GRP increased pancreatic weight, total pancreatic protein, trypsin and amylase content. The DNA content was also increased by both peptides, although only the GRP effect proved to be significant. These results demonstrate that both bombesin and GRP have a growth-promoting effect on rat pancreas and concomitantly increase its secretory capacity. The mechanism of this peculiar biological action is likely to be connected with a direct stimulatory action on the gland.

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“…25 Whereas the direct eect of bombesin (of which GRP is the mammalian counterpart) is stimulatory on insulin release, the overall in vivo eect may be inhibitory due to a delay in gastric emptying and glucose uptake. 26 GRP has only a short insulinotropic eect. 27 Both the incretins for rats, cholecystokinin (CCK 8 ) and glucose-dependent insulinotropic peptide (GIP), have small and short-term eects 14,28 when released after food uptake.…”

Section: Introductionmentioning

confidence: 99%

Modulation of gastrin-releasing peptide (GRP) receptors in insulin secreting cells

Kloss

Wahl

Neye

et al. 1999

Cell Biochem. Funct.

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Gastrin-releasing peptide (GRP) receptors are present in pancreatic islets, though their regulation is unknown except for homologous desensitization. The modulation of binding of GRP to mouse pancreatic islets and INS-1 cells was studied. At 60 min (steady-state), total binding of [(125)I-Tyr(15)] GRP was 1.62 per cent of total radioactivity per 50 islets; non-specific binding (presence of 1 mM unlabelled GRP(1-27)) was 0.05 to 0.61 per cent of total radioactivity. A preincubation with 1000 nM cholecystokinin (CCK(8)) or with 1000 nM glucose-dependent insulinotropic peptide (GIP) augmented the number of GRP binding sites but not their affinity. [(125)I-Tyr(15)]GRP binding to INS-1 cells was saturable (90 min) and specific with respect to compounds that are not chemically related to GRP (e.g. calcitonin gene-regulated peptide-CGRP and atrial natriuretic peptide-ANP). Displacement studies showed one binding site with a K(d) of 0.39 nM and a B(max) of 13.2 fmoles mg(-1) protein. When the cells were pretreated for 24 h with 10 nM GIP or CCK(8), only GIP but not CCK(8) increased the B(max) of the GRP binding site. The affinity (K(d)) was not changed by either compound. This effect of GIP pretreatment was not affected by downregulating PKC by TPA (phorbol ester; long-term pretreatment). These data indicate that: (1) specific binding sites for GRP are present in mouse pancreatic islets and INS-1 cells; (2) the GRP binding is upregulated by GIP in both islets and INS-1 cells and additionally by CCK(8 ), albeit only in islets; and (3) PKC does not seem to be involved in the up-regulation process. Thus a positive interplay between both the incretins GIP and CCK(8) and the neurotransmitter GRP is obvious.

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Effect of Bombesin on Glucose-Induced Insulin Release in Humans

Cited by 4 publications

References 26 publications

Different effects of bombesin on glucose‐ and tolbutamide‐induced insulin release in man

Different effects of bombesin on glucose‐ and tolbutamide‐induced insulin release in man

Effect of Bombesin and Its Mammalian Counterpart, GRP, on Exocrine Pancreas in the Rat

Modulation of gastrin-releasing peptide (GRP) receptors in insulin secreting cells

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