Action of cholecystokinin analogues on exocrine and endocrine rat pancreas

1986 ◽  
Vol 250 (4) ◽  
pp. G405-G411
Author(s):  
M. Otsuki ◽  
Y. Okabayashi ◽  
A. Ohki ◽  
T. Oka ◽  
M. Fujii ◽  
...  
Keyword(s):  
Amino Acid ◽  
Insulin Release ◽  
Pancreatic Enzyme ◽  
Exocrine Secretion ◽  
Amino Acid Residues ◽  
Isolated Perfused Pancreas ◽  
Pancreatic Acini ◽  
Rat Pancreas ◽  
Pancreatic Exocrine ◽  
Stimulation Of

In the present study we have examined the abilities of cholecystokinin-(26-33)-amide [CCK-(26-33)-NH2, CCK-8], nonsulfated CCK-(26-33)-NH2 (desulfated CCK-8), CCK-(30-33)-NH2 (CCK-4), CCK-(26-33)-OH (deamidated CCK-8), and succinyl CCK-(27-31)-NH2 (Suc-Des-Asp6,Phe7-CCK-7) to stimulate exocrine pancreatic secretion from both isolated pancreatic acini and isolated perfused pancreas. We have also compared this action with their ability to cause insulin release. The modification of either the N- or C-terminal amino acid residues of CCK-8 decreased in potency, but the magnitude of the stimulation of enzyme secretion caused by a maximally effective peptide concentration was the same. The minimal effective concentration of CCK-8, desulfated CCK-8, and CCK-4 for insulin release from the isolated rat pancreas in the presence of 8.3 mM glucose was the same as that for pancreatic exocrine secretion. In contrast, the concentrations of deamidated CCK-8 and Suc-Des-Asp6,Phe7-CCK-7 required to produce insulin release were 5-10 times higher than those required to cause stimulation of pancreatic enzyme and juice secretion. It is concluded therefore that the N-terminal 4-amino acid residues or the C-terminal 2-amino acid residues of CCK-8 are not essential for biological activity but do contribute to its potency. In addition, the C-terminal 2-amino acid residues and an amide group in the C-terminal phenylalanine residue of CCK-8 appear to be important determinants of the insulin-releasing activity of the CCK peptides.

Effects of neuromedin B and neuromedin C on exocrine and endocrine rat pancreas

1987 ◽  
Vol 252 (4) ◽  
pp. G491-G498 ◽  
Author(s):  
M. Otsuki ◽  
M. Fujii ◽  
T. Nakamura ◽  
S. Tani ◽  
T. Oka ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Insulin Release ◽  
Exocrine Secretion ◽  
Exocrine Pancreatic Function ◽  
Isolated Perfused Pancreas ◽  
Amylase Release ◽  
Pancreatic Acini ◽  
Neuromedin B ◽  
Pancreatic Exocrine ◽  
Stimulate Insulin Release

Neuromedin B and neuromedin C are novel decapeptides that have recently been isolated from porcine spinal cord and canine intestinal mucosa and show striking sequence homology with bombesin and gastrin-releasing peptide (GRP-27) at the carboxyl-terminal region. The effects of synthetic neuromedin B and C on exocrine pancreatic function and insulin release have been compared with bombesin and GRP-27 in isolated pancreatic acini and isolated perfused pancreas in rat. Neuromedin B and C as well as bombesin and GRP-27 were able to cause stimulation of amylase release. The relative efficacy of neuromedin B, C, bombesin, and GRP-27 was the same as that of cholecystokinin octapeptide (CCK-8). Bombesin and GRP-27 were equipotent, and both were approximately 15-fold less potent than CCK-8. Neuromedin C was approximately 2-fold more potent, whereas neuromedin B as approximately 10-fold less potent than bombesin and GRP-27. All of these peptides stimulated insulin release that was limited to the first 3 min of a 20-min perfusion. However, GRP-27 and its related peptides were weak stimulants of insulin release compared with their abilities to stimulate exocrine pancreatic secretion. Bombesin and neuromedin B id not stimulate insulin release at doses stimulating pancreatic exocrine secretion. Neuromedin B was also approximately 10-fold less potent than neuromedin C, bombesin, and GRP-27 in eliciting insulin secretion. Because bombesin-like immunoreactivity is found to be present in nerves in the pancreas, neuromedin B and C may be neurotransmitters or neuromodulators and exert a direct local neurocrine action on enzyme secretion by acinar cells and insulin secretion by the islets.

Insulin action in pancreatic acini from streptozotocin-treated rats. I. Stimulation of protein synthesis

1981 ◽  
Vol 240 (1) ◽  
pp. G56-G62 ◽  
Author(s):  
M. Korc ◽  
Y. Iwamoto ◽  
H. Sankaran ◽  
J. A. Williams ◽  
I. D. Goldfine
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Cell Concentration ◽  
Enzyme Synthesis ◽  
Detectable Effect ◽  
Leucine Incorporation ◽  
Maximal Effect ◽  
Pancreatic Acini ◽  
Pancreatic Exocrine ◽  
Stimulation Of

Pancreatic acini were prepared from rats rendered diabetic with streptozotocin. In this tissue, insulin stimulated [3H]leucine incorporation into protein. The full effects of insulin on this function were not immediate but increased linearly with time for up to 2 h of incubation. Insulin had a detectable effect on l eucine incorporation at 50 pM, a half-maximal effect at 0.7 nM, and a maximal effect at 30 nM. Desdipeptide proinsulin was only 10% as potent as native insulin in stimulating [3H]leucine incorporation, whereas proinsulin and desoctapeptide insulin were only 1% as potent. Insulin also increased the incorporation of [3H]valine and [35S]methionine into protein but did not increase the influx of either [14C]cycloleucine or alpha-[3H]aminoisobutyric acid. These observations suggested that the increased incorporation of labeled amino acid into protein reflected stimulation of protein synthesis rather than stimulation of amino acid transport. Furthermore, insulin at 1.67 nM significantly increased the acinar cell concentration of amylase. The present findings are consistent therefore with the concept that insulin regulates pancreatic exocrine functions, including protein and enzyme synthesis.

scholarly journals Age-associated changes in pancreatic exocrine secretion of the isolated perfused rat pancreas

2013 ◽  
Vol 29 (1) ◽  
pp. 19 ◽  
Author(s):  
Zheng-er Jiang ◽  
ChengZhe Jiang ◽  
Baihui Chen ◽  
Chin Su Koh ◽  
Jun-Hwan Yong ◽  
...  
Keyword(s):  
Exocrine Secretion ◽  
Pancreatic Exocrine Secretion ◽  
Perfused Rat Pancreas ◽  
Rat Pancreas ◽  
Isolated Perfused Rat Pancreas ◽  
Pancreatic Exocrine

Effect of galanin on glucose-, arginine-, or potassium-stimulated insulin release

1989 ◽  
Vol 256 (5) ◽  
pp. E619-E623
Author(s):  
T. Yoshimura ◽  
J. Ishizuka ◽  
G. H. Greeley ◽  
J. C. Thompson
Keyword(s):  
Insulin Release ◽  
High Glucose ◽  
Second Phase ◽  
Dependent Manner ◽  
Perfused Pancreas ◽  
Isolated Perfused Pancreas ◽  
Second Phases ◽  
High Concentrations ◽  
Dose Dependent ◽  
Stimulation Of

We have examined the effect of galanin infusion on glucose-stimulated release of insulin from the isolated perfused pancreas of the rat to better characterize the effect of galanin on the first and second phases of insulin release. The effects of galanin on insulin release stimulated by L-arginine or high concentrations of potassium were also examined. When perfusion of galanin was started 4 min before the start of perfusion of high glucose (16.7 mM), galanin (10(-8)-10(-11) M) inhibited both the first and second phases of insulin release in a dose-dependent manner. When perfusion of galanin (10(-8) or 10(-9) M) was started simultaneously with high glucose (16.7 mM), only the second phase of insulin release was suppressed (P less than 0.05). Galanin (10(-9) M) failed to inhibit insulin release stimulated by L-arginine (10 and 5 mM) or potassium (25 and 20 mM). These findings suggest that the inhibitory action of galanin on glucose-stimulated insulin release is exerted on early intracellular events that occur during the stimulation of insulin release and that are common to both phases. Because galanin does not inhibit insulin release stimulated by L-arginine or potassium, galanin may inhibit glucose-stimulated closure of potassium channels.

Gastrin-releasing peptide: effect on exocrine secretion and release from isolated perfused porcine pancreas

1985 ◽  
Vol 248 (3) ◽  
pp. G281-G286 ◽  
Author(s):  
S. Knuhtsen ◽  
J. J. Holst ◽  
S. L. Jensen ◽  
U. Knigge ◽  
O. V. Nielsen
Keyword(s):  
Exocrine Secretion ◽  
Arterial Line ◽  
Pancreatic Exocrine Secretion ◽  
Vagus Nerves ◽  
Porcine Pancreas ◽  
Gastrin Releasing Peptide ◽  
Atropine Treatment ◽  
Pancreatic Exocrine ◽  
Control Fluid ◽  
Stimulation Of

The effect of gastrin-releasing peptide (GRP) on pancreatic exocrine secretion was studied by infusing it at four dose levels (0.01, 0.1, 1.0, and 10 nmol/l) into the arterial line of the isolated perfused porcine pancreas. At 1.0 nmol/l GRP stimulated protein (37-fold), fluid (13-fold), and bicarbonate secretion (12-fold). Atropine at 1 mumol/l diminished the protein secretion in response to infusion of GRP at a dose of 1 nmol/l to 45% of control. Fluid and bicarbonate responses were not affected by atropine treatment. Electrical stimulation of the vagus nerves resulted in an increase in pancreatic output of GRP and a concomitant stimulation of exocrine secretion. Infusions of acetylcholine, carbachol, pilocarpine, or dimethylphenylpiperazinium had no effect on the output of GRP, although hexamethonium abolished the response to vagal stimulation. It is concluded that GRP in conjunction with acetylcholine is likely to play a prominent part in parasympathetic regulation of pancreatic exocrine secretion.

Structural requirements of peptide YY for biological activity at enteric sites

1992 ◽  
Vol 263 (5) ◽  
pp. G695-G701 ◽  
Author(s):  
K. Yoshinaga ◽  
T. Mochizuki ◽  
N. Yanaihara ◽  
K. Oshima ◽  
M. Izukura ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Acid Secretion ◽  
Gastric Acid Secretion ◽  
Gastric Acid ◽  
Insulin Release ◽  
Peptide Yy ◽  
Exocrine Secretion ◽  
Pancreatic Exocrine Secretion ◽  
Structural Requirements ◽  
Pancreatic Exocrine

Peptide YY (PYY) is a colonic hormone consisting of 36 amino acids that is a potent inhibitor of pancreatic exocrine, gastric acid, and insulin secretion. The objective of the present experiments was to characterize the structural requirements of PYY for inhibition of pancreatic exocrine, gastric acid, and insulin secretion, using conscious dogs prepared with gastric and pancreatic fistulas. Intravenous administration of PYY-(1-36), PYY-(3-36), or PYY-(4-36) (400 pmol.kg-1 x h-1) inhibited cholecystokinin-8-stimulated (25 pmol.kg-1 x h-1) pancreatic exocrine secretion (P < 0.05); however, PYY-(1-10), PYY-(1-20), PYY-(6-36), PYY-(10-36), PYY-(13-36), PYY-(24-36), and PYY-(27-36) did not inhibit pancreatic exocrine secretion. Intravenous administration of PYY-(1-36), PYY-(3-36), or PYY-(4-36) (200, 400, 800 pmol.kg-1 x h-1) inhibited pentagastrin (0.5 microgram.kg-1 x h-1)-stimulated gastric acid secretion (P < 0.05), as well as 2-deoxy-D-glucose-stimulated insulin release (75 mg/kg) in a dose-related manner. PYY-(6-36), PYY-(13-36), and [Leu31, Pro34] neuropeptide Y did not inhibit either gastric acid secretion or insulin release. In the gastric acid and insulin secretion bioassays, PYY-(1-36) was significantly more potent than PYY-(3-36) and PYY-(4-36); however, in the pancreatic exocrine secretion bioassay, the inhibitory effects of PYY-(3-36) and PYY-(1-36) did not differ significantly. PYY-(4-36) was less potent than PYY-(1-36) on pancreatic exocrine secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulation of rat pancreatic exocrine secretion by urocortin and corticotropin releasing factor

Peptides ◽  
2003 ◽  
Vol 24 (5) ◽  
pp. 727-734 ◽  
Author(s):  
Eduardo A Guzman ◽  
Weizhen Zhang ◽  
Theodore R Lin ◽  
Michael W Mulholland
Keyword(s):  
Exocrine Secretion ◽  
Corticotropin Releasing Factor ◽  
Pancreatic Exocrine Secretion ◽  
Pancreatic Exocrine ◽  
Stimulation Of
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