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Nilsson O, Bilchik AJ, Goldenring JR, Ballantyne GH, Adrian TE, Modlin IM. Distribution and immunocytochemical colocalization of peptide YY and enteroglucagon in endocrine cells of the rabbit colon. Endocrinology 1991; 129:139-48. [PMID: 1675986 DOI: 10.1210/endo-129-1-139] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Peptide YY (PYY) is 36 amino acid peptide hormone present in high concentrations in the colon where it is colocalized with enteroglucagon in L cells. A selective release of PYY and enteroglucagon from the rabbit colon has been described, raising the question of the exact localization of the two hormones in the rabbit colon. We have therefore examined the distribution of PYY and enteroglucagon as well as somatostatin in the rabbit colon using RIA and electron microscopic immunocytochemistry. PYY and enteroglucagon were present in high concentrations in the colorectal mucosa with peak concentrations in the left colon (PYY 544 +/- 87 pmol/g, enteroglucagon 152 +/- 10 pmol/g). Electron microscopic examination of the colonic mucosa demonstrated a large population (65%) of EC cells, a moderate population (30%) of L cells, and a small population (5%) of D cells. By immunogold labeling serotonin was localized to EC cells, PYY and enteroglucagon to L cells, and somatostatin to the D cell. Double immunogold labeling revealed PYY and enteroglucagon in all L cells examined (93 cells). A majority of the secretory granules (83%) were labeled by both PYY and glucagon antibodies, whereas a significant portion of granules (15%) was labeled by the PYY antibodies alone. The results demonstrate that L cells are the sole source of PYY and enteroglucagon in the rabbit colon and that L cells contain different populations of secretory granules. The existence of different secretory granules in L cells may explain the selective release of PYY and enteroglucagon observed in the rabbit colon.
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Longo WE, Ballantyne GH, Savoca PE, Adrian TE, Bilchik AJ, Modlin IM. Short-chain fatty acid release of peptide YY in the isolated rabbit distal colon. Scand J Gastroenterol 1991; 26:442-8. [PMID: 2034997 DOI: 10.3109/00365529108996507] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Short-chain fatty acids (SCFAs) form the major ionic fraction of stool, provide the major metabolic substrate for colonic epithelium, and promote mucosal ion transport. Despite this prominent role of SCFAs in metabolism of the colon, their effect on colonic endocrine cell function has not been studied. Consequently, we hypothesized that SCFAs might modulate release of peptide YY (PYY) from colonic type-L endocrine cells. The specific aims of this study were to measure release of PYY from the isolated perfused rabbit distal colon stimulated by intraluminal infusion of 0.9% saline, acetate (10 mM), acetoacetate (10 mM), n-butyrate (1, 3.3, 10, 100 mM), and pyruvate (10 mM). PYY levels were measured by radioimmunoassay in the venous effluent of the rabbit colon. All four SCFAs (10 mM) caused at least a twofold increase in integrated release of PYY from the isolated perfused rabbit colon. Graded concentrations of n-butyrate caused a stepwise release of PYY. This study suggests that SCFAs may modulate the release of colonic PYY in rabbits.
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Bilchik AJ, Zucker KA, Adrian TE, Modlin IM. Amelioration of cholinergic-induced pancreatitis with a selective cholecystokinin receptor antagonist. ARCHIVES OF SURGERY (CHICAGO, ILL. : 1960) 1990; 125:1546-9. [PMID: 2244806 DOI: 10.1001/archsurg.1990.01410240024004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Acute edematous pancreatitis follows excessive cholinergic stimulation in patients exposed to anticholinesterase-containing insecticides. We describe the role of cholecystokinin and the benefits of cholecystokinin receptor blockade in this form of pancreatitis. A cholinergic mimetic (carbachol) was administered to rats weighing 300 to 350 g and produced a form of edematous pancreatitis that mimics that seen in humans. Animals received carbachol intraperitoneally, either alone (250 micrograms/kg of body weight) or with cholecystokinin-receptor antagonist devazepide (3 mg/kg of body weight) and were killed 4 hours later. Carbachol administration resulted in a 19% increase in pancreatic weight, a fourfold increase in serum amylase levels, and a 14-fold increase in serum lipase levels. Plasma cholecystokinin levels, however, were not altered. Devazepide administered prior to cholinergic hyperstimulation blocked pancreatic weight increase and reduced elevations in serum amylase levels twofold and lipase levels fourfold. Although cholecystokinin levels are not elevated in this model of pancreatitis, blockade of even low, background concentrations of this regulatory peptide is beneficial.
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Modlin IM, Basson MD, Adrian TE, Sussman J. Pepsinogen release and acid secretion from human and guinea pig gastric mucosa compromised by hypoxia, endotoxin, or critical illness. Scand J Gastroenterol 1990; 25:865-75. [PMID: 2218392 DOI: 10.3109/00365529008997606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Despite blockade and neutralization of gastric acid, acute gastric lesions cause substantial morbidity and mortality in critically ill patients. Pepsinogen release in response to noxious stimuli such as hypoxia and endotoxin might contribute to mucosal damage. Guinea pig fundic mucosa was mounted in Ussing chambers. Acid secretion, pepsinogen release, potential difference (PD), and resistance were monitored. Gassing with room air or nitrogen diminished acid secretion and PD but increased pepsinogen release 9.7- and 15.5-fold, respectively (both p less than 0.001). Similarly, endotoxin (0.01 and 0.1 units/ml) dose-dependently inhibited acid secretion and PD but increased pepsinogen release 3.3- and 6.1-fold (both p less than 0.05). Endotoxic and air-gassed tissues were edematous with scattered cellular damage by light and transmission electron microscopy; nitrogen-exposed membranes appeared necrotic. Pepsin release may therefore have resulted from cell damage rather than exocytosis. Intragastric peptic activity in critically ill H2-receptor-blocked patients (n = 20) was 5490 +/- 1701 U/ml. The gastric juice of H2-blocked convalescing surgical patients (n = 20) contained 315 +/- 101 U/ml (p less than 0.0001). Occult blood correlated with intragastric peptic activity (r = 0.59, p less than 0.0001) but not with gastric pH (r = 0.04, p = 0.6). These data suggest that the complex of pathophysiologic abnormalities common in critical illness causes substantial pepsin release. Efflux of this potent mucolytic barrier breaker may damage gastric mucosa in severely stressed patients.
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Basson MD, Adrian TE, Modlin IM. Effects of cholecystokinin and cholinergic receptor blockade on guinea pig pepsinogen secretion. Scand J Gastroenterol 1990; 25:825-33. [PMID: 2402588 DOI: 10.3109/00365529008999222] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Although cholecystokinin (CCK) has been reported to stimulate pepsinogen secretion, this action has been poorly characterized. To assess the ability of CCK to regulate mammalian pepsinogen secretion, guinea pig fundic mucosa was incubated in Ussing chambers with CCK-8, carbamylcholine, and pentagastrin, and with cholinergic and CCK antagonists. CCK-8 stimulated pepsinogen secretion at 10(-10) M, with an ED50 of 10(-9) M and maximally (26-fold over basal) at 10(-8) M. Carbachol stimulated pepsinogen and acid secretion with an ED50 of 3 x 10(-7) M and maximally at 10(-6) M. Pentagastrin (10(-9) M-10(-6) M) did not affect acid or pepsinogen secretion, whereas gastrin-I (10(-6) M) stimulated acid secretion slightly but did not alter pepsinogen secretion. L364, 718 (10(-5) M), a specific CCK peripheral receptor antagonist, abolished all pepsigogic effects of 3 x 10(-9) M CCK-8 without altering basal acid or pepsinogen secretion or mucosal electric characteristics. L364,718-treated tissues unresponsive to CCK-8 nevertheless secreted pepsinogen and acid in response to 3 x 10(-7) M carbachol identically to control carbachol-treated preparations. Atropine (10(-5) M) blocked the response to 3 x 10(-7) M carbachol without inhibiting 10(-9) M CCK stimulation. These results support a specific receptor-mediated role for cholecystokinin in the physiologic regulation of guinea pig pepsinogen secretion.
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Nilsson O, Bilchik AJ, Adrian TE, Modlin IM. Intra-ocular transplantation of carcinoid tumours from mastomys and humans. J Pathol 1990; 160:347-56. [PMID: 2358971 DOI: 10.1002/path.1711600412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Carcinoid tumours from man and Mastomys (Praomys) natalensis produce a variety of peptide hormones. The study of these peptide-secreting tumours has been difficult because of the small amount of tissue available and because of limitations with present cell culture systems. The aim of this study was to establish an experimental model where carcinoid tumours could be maintained and their hormone secretion studied. The intra-ocular transplantation technique was chosen for its simplicity and high rate of success. Gastric carcinoid tumours from mastomys (n = 4) and human carcinoids (n = 2) (one bronchial and one ileal) were transplanted to the anterior eye chamber of Sprague-Dawley rats. Pieces of fresh tumour tissue were injected into the anterior eye chamber of rats and allowed to grow for 4-8 weeks. Rats transplanted with human tissue were immunosuppressed by daily injections with cyclosporin A (20 mg/kg). Eye chambers were inspected regularly and plasma from transplanted rats was collected for assay of peptide YY (PYY) and glucagon. Vascularization of transplants occurred within 1-2 days after transplantation in 70-80 per cent of all experiments. Microscopic analysis of transplants demonstrated a rich supply of blood vessels to tumour cells which contained characteristic neurosecretory granules. Transplanted rats had significantly (P less than 0.05) elevated levels of PYY (44-165 pmol/l) and glucagon (67-162 pmol/l) in plasma as compared with sham-operated rats (PYY 28-40 pmol/l, glucagon 33-40 pmol/l), indicating that hormone secretion by tumour cells in oculo was maintained.(ABSTRACT TRUNCATED AT 250 WORDS)
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Bilchik AJ, Nilsson O, Modlin IM, Zucker KA, Adrian TE. Significance of gastric endocrine tumor and age-related gut peptide alterations in Mastomys. REGULATORY PEPTIDES 1990; 27:195-207. [PMID: 2326498 DOI: 10.1016/0167-0115(90)90039-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The Mastomys (Praomys natalensis) species are a unique natural model in which the bioactivity of gastric carcinoids may be studied. Several investigators have previously demonstrated that these tumors contain large amounts of histamine. In this study we investigated the presence of peptides associated with the neoplasm. The levels and location of gastrin, gastric inhibitory peptide (GIP), neurotensin, peptide YY (PYY), pancreatic polypeptide (PP), glucagon, bombesin, vasoactive intestinal peptide (VIP) and somatostatin (SRIF) were investigated by radioimmunoassay and immunocytochemistry. In addition the distribution of these peptides were evaluated in the gastrointestinal tract of young and old animals to investigate possible age-related changes. PYY and enteroglucagon (EG) were significantly (P less than 0.001) elevated in both tumor tissue (676 +/- 152, 551 +/- 164 pmol/g) and plasma (620 +/- 160, 500 +/- 147 pmol/l) of tumor-bearing animals. Immunocytochemistry revealed PYY- and EG-like immunoreactivity in 20-30% of tumor cells. A significant decrease (P less than 0.05) in bombesin was noted in older animals, but no changes in gastric tissue content of PYY or EG could be detected between young and old animals. Gastrin was not detected in tumors and there were no significant changes in tissue or plasma levels with age. Small bowel concentrations of VIP and PYY were higher in the older mastomys (P less than 0.05). In contrast, colonic levels of bombesin, VIP, somatostatin and PYY were significantly lower (P less than 0.05) in older mastomys compared with young. The age-related changes in several peptides may reflect an adaptive response to acid hypersecretion. The multi-hormonal character of these neoplasms suggests that these tumors develop from a pluripotential stem cell.
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Adrian TE, Zucker KA, Bilchik AJ, Modlin IM. A novel micromethod for pancreatic acinar secretion. Time course of CCK stimulation and its inhibition by L-364,718. INTERNATIONAL JOURNAL OF PANCREATOLOGY : OFFICIAL JOURNAL OF THE INTERNATIONAL ASSOCIATION OF PANCREATOLOGY 1990; 6:61-9. [PMID: 1700032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dispersed acini have proven to be particularly valuable in the study of pancreatic enzyme secretion. Complex time course studies or experiments requiring large numbers of replicates have proven difficult, however, with currently available techniques. Using a custom-designed incubation chamber, a miniaturized incubation method has been devised, which allows for continuous oxygenation of acini in 96-well microtiter plates and rapid separation of medium from acini by vacuum filtration. The filtrates from individual wells are collected into the wells of a second microtiter plate for pancreatic enzyme measurement. Using the above method, the dose response and time course of cholecystokinin (CCK-8)-stimulated amylase secretion was investigated. During a 1-h incubation, unstimulated amylase secretion was 4.1 +/- 0.3% of total acini content. Response to CCK was very sensitive, being detected at 10(-13) M (p less than 0.05), half-maximal at 10(-11) M CCK (14.0 +/- 0.6%, p less than 0.001) and maximal at 10(-9) M CCK (24.8 +/- 1.0%, p less than 0.001). In the time course experiments, an increase in amylase secretion was detected by 2.5 min and continued to increase steadily to a plateau at 40 min, with both submaximal (10(-11) M) and maximal (10(-9) M) CCK concentrations. The potent and specific CCK-receptor antagonist, L-364,718, caused a dose-dependent decrease in CCK-stimulated amylase secretion, with a half-maximal effect at 10(-10) M. The receptor antagonist, L-364,718, at 10(-8) M completely abolished CCK-stimulated amylase secretion. This microtechnique provides a simple, reliable, and reproducible method for the study of dispersed pancreatic acini.(ABSTRACT TRUNCATED AT 250 WORDS)
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Zdon MJ, Lewis JJ, Adrian TE, Modlin IM. Hypergastrinemia after vagotomy is not associated with decreased gastric somatostatin. Surgery 1989; 106:1074-80. [PMID: 2573954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Although hypergastrinemia occurs after vagotomy, the mechanisms responsible are not understood. Somatostatin (SRIF) is a peptide that inhibits gastrin release, is present within the gastric fundus and antrum, and is under vagal control. In this study we have investigated the hypothesis that hypergastrinemia is associated with a decrease in gastric SRIF. We examined tissue levels of SRIF in gastric mucosa and muscle wall in rabbits undergoing vagotomy and pyloroplasty compared with sham-operated controls. We also compared the release of SRIF from gastric glands in response to vasoactive intestinal peptide and calcitonin gene-related peptide. Vagotomy resulted in an increase in gastrin compared with controls in both antrum (1062 +/- 176 pmol/gm vs 484 +/- 48 pmol/gm) and plasma (236 +/- 72 pmol/L vs 29 +/- 4 pmol/L; p less than 0.05). This was accompanied by an increase in the number of gastrin cells (25 +/- 4 vs 9 +/- 3; p less than 0.05). No significant differences were observed in gastric SRIF levels in either the fundus or antrum (p greater than 0.5). In addition, there were no differences in the release of SRIF from gastric glands of vagotomized animals compared with controls in response to vasoactive intestinal peptide and calcitonin gene-related peptide (p greater than 0.5). These data suggest that the elevations in plasma and antral gastrin levels after vagotomy are not a result of alterations in gastric SRIF.
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Zucker KA, Bilchik AJ, Modlin IM, Adrian TE. Prostaglandin E analogue inhibition of pancreatic enzyme secretion. Pancreas 1989; 4:708-14. [PMID: 2479001 DOI: 10.1097/00006676-198912000-00009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effect of native prostaglandins and their methylated analogues on pancreatic enzyme secretion remains unclear, with previous studies reporting inconsistent results. To determine whether the E series prostaglandins directly influence pancreatic secretion, we studied the effect of rioprostil, a prostaglandin E1 analogue, and 16,16-dimethyl prostaglandin E2 (DMPGE2), a prostaglandin E2 analogue, on enzyme release from dispersed guinea pig pancreatic acini. Basal amylase release (4.3 +/- 0.6% of total acinar content) was not altered by either analogue (10(-10)-10(-5) M). A 50% inhibition of maximal cholecystokinin stimulation (10(-9) M; 28.8 +/- 1.2%) was seen with rioprostil (10(-7) M; 14.6 +/- 1.3%) and DMPGE2 (10(-6) M; 15.9 +/- 0.7%) (both p less than 0.005). Prostaglandin inhibition of carbachol-stimulated amylase was less pronounced. The most effective inhibitory dosage with maximal carbachol (10(-5) M; 30.2 +/- 1.9%) was 10(-6) M for both rioprostil (19.2 +/- 1.6%) and DMPGE2 (22.4 +/- 1.7%) (both p less than 0.005). Incubation of acini with A23187, phorbol ester, and 1-oleoyl-2-acetyl-glycerol resulted in a dose-dependent increase in amylase release that was not altered by maximal concentrations of either prostaglandin analogue. Our results indicate that rioprostil and DMPGE2 can directly inhibit pancreatic acinar secretion. This effect appears to occur before activation of the inositol phospholipid system.
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Bilchik AJ, Nilsson O, Modlin IM, Sussman J, Zucker KA, Adrian TE. H2-receptor blockade induces peptide YY and enteroglucagon-secreting gastric carcinoids in mastomys. Surgery 1989; 106:1119-26; discussion 1026-7. [PMID: 2573958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Gastric carcinoid tumor formation has been reported with prolonged achlorhydria in both animals and human beings. The hypothesis in this study was that the ablation of parietal cell function in an animal (mastomys) genetically predisposed to gastric neuroendocrine neoplasia would promote and accelerate tumor formation. Loxtidine, an irreversible H2-receptor blocker, was administered at 1 mg/kg/day in drinking water for 4 months to young mastomys (n = 16). After 4 months of treatment, 14 of 16 animals had gastric carcinoids compared with 0 of 16 young control animals and 4 of 16 older control animals. Ultrastructurally, these tumors were characterized by the presence of neurosecretory granules. Serum gastrin levels were elevated (230 +/- 40 pmol/L) in loxtidine-treated animals compared with control animals (26 +/- 8 pmol/L) (p less than 0.05). In addition, both peptide YY (620 +/- 160 pmol/L) and enteroglucagon (500 +/- 147 pmol/L) were significantly elevated compared with control groups (p less than 0.05). Similarly, in tumor tissue, peptide YY (676 +/- 152 pmol/gm) and enteroglucagon (551 +/- 164 pmol/gm) were found in large quantities, whereas gastrin was undetectable. These observations provide substantial support for the possible pathophysiologic role of gut peptides, particularly gastrin, in the generation of endocrine neoplasia. The advent of endocrine tumors after inhibition of a gut secretory cell (parietal) may be of considerable significance in understanding the genesis of endocrine neoplasia. Whether the drug acts as a neoplastic promoter of enterochromaffin-like cells or the tumor development is related to elevation of peptides such as gastrin cannot be established in this study. Long-term H2-receptor blockade with new potent, irreversible agents as an alternative to surgery may have potential grave implications that require careful consideration.
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Ballantyne GH, Longo WE, Savoca PE, Adrian TE, Vukasin AP, Bilchik AJ, Sussman J, Modlin IM. Deoxycholate-stimulated release of peptide YY from the isolated perfused rabbit left colon. THE AMERICAN JOURNAL OF PHYSIOLOGY 1989; 257:G715-24. [PMID: 2596607 DOI: 10.1152/ajpgi.1989.257.5.g715] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The purpose of this study was 1) to measure the effect of graded concentrations of oleic acid and deoxycholic acid (DCA) on the release of peptide YY (PYY) and enteroglucagon and 2) to test whether DCA-stimulated release of PYY was neurally mediated by blocking neuronal conduction with tetrodotoxin. Studies were performed in isolated left colons from New Zealand White rabbits. Oleic acid in concentrations from 0.22 to 22 mM suspended in 10 mM DCA significantly stimulated release of PYY (P less than 0.01) but resulted in no graded response (Bartlett's test, P = 0.15). Similarly, oleic acid (2.2 mM) suspended with ursodeoxycholic acid (10 mM) produced no increased release of PYY above that achieved by ursodeoxycholic acid alone. In contrast, oleic acid (2.2 and 22 mM suspended with 10 mM DCA) produced a graded release of enteroglucagon during the stimulated period. Deoxycholic acid caused a concentration-dependent release of PYY (1, 3.3, 10, and 25 mM) during the stimulated period. Deoxycholic acid (1 and 10 mM) did not significantly increase enteroglucagon release. Tetrodotoxin blockade had no effect on release of PYY stimulated by 10 mM DCA. Because PYY and enteroglucagon are both found in colonic endocrine cells, these results suggest that the release of PYY and enteroglucagon are mediated by specific secretagogues and not simply caused by noxious effects of the agonists. Also, this study has demonstrated that DCA-stimulated release of PYY is not dependent on neuronally mediated mechanisms.
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Adrian TE, Goldenring JR, Oddsdottir M, Zdon MJ, Zucker KA, Lewis JJ, Modlin IM. A micromethod for the assay of cellular secretory physiology: application to rabbit parietal cells. Anal Biochem 1989; 182:346-52. [PMID: 2558591 DOI: 10.1016/0003-2697(89)90606-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A micromethod for investigating secretory physiology in isolated cells was evaluated. The method utilized a specially designed polycarbonate incubation chamber to provide constant oxygenation to cells incubating in a 96-well microtiter plate. Cells were rapidly separated from media by vacuum filtration. Isolated parietal cells were utilized to demonstrate the versatility of the method for assay of intracellular accumulation of [14C]-aminopyrine, secretion of intrinsic factor into the medium, and assay of intracellular cAMP. Histamine stimulated the uptake of [14C]aminopyrine and intrinsic factor secretion in a sustained and linear fashion. At the end of the 2-h period uptake of aminopyrine and secretion of intrinsic factor were increased 17- and 5-fold, respectively. This response to histamine was accompanied by a rapid and sustained 3-fold rise in intracellular cyclic AMP. In contrast, carbamylcholine caused a transient increase in [14C]aminopyrine accumulation and intrinsic factor secretion which was most pronounced during the first 10 min and had almost ceased by 30 min. Carbamylcholine had no effect on intracellular cAMP levels. This new method, which can handle 400 replicates using parietal cells from the fundic mucosa of a single rabbit, is suitable for studying the time course of intracellular events which accompany general secretory processes.
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Zucker KA, Adrian TE, Bilchik AJ, Modlin IM. Effects of the CCK receptor antagonist L364,718 on pancreatic growth in adult and developing animals. THE AMERICAN JOURNAL OF PHYSIOLOGY 1989; 257:G511-6. [PMID: 2478030 DOI: 10.1152/ajpgi.1989.257.4.g511] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Although exogenous administration of cholecystokinin (CCK) or dietary manipulation to increase circulating CCK have previously been shown to promote pancreatic growth, the role of CCK in controlling normal pancreatic development remains unclear. A potent CCK receptor antagonist, L364,718, was administered to rats, guinea pigs, and hamsters to block the effect of endogenous CCK. Animals were given continuous infusions of L364,718 (25 nmol.kg-1.h-1), CCK octapeptide [(CCK-8) 200 pmol.kg-1.h-1], or both CCK-8 and L364,718 for 14 and 28 days. Adult (4-mo-old) and young (4-wk-old) animals were used. CCK-8 and L364,718 were administered via separate, subcutaneously implanted mini-osmotic pumps. Infusions of CCK-8 alone for 28 days resulted in a 21.7% increase in wet pancreatic weight in 4-wk-old rats and a 22.7% increase in 4-wk-old guinea pigs (both P less than 0.001 compared with controls). Similar increases were found in DNA, RNA, and total protein contents. Coadministration of L364,718 totally blocked the trophic effects of exogenously infused CCK-8 in rats and guinea pigs. Administration of L364,718 alone in hamsters, guinea pigs, and rats for 14 and 28 days failed to alter the normal growth of the pancreas gland as measured by these parameters. Although elevated levels of CCK appear to promote a potent trophic response in the growing pancreas, this regulatory peptide does not appear to be an essential trophic factor for the normal growth of the exocrine pancreas in these animals.
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Calam J, Ghatei MA, Domin J, Adrian TE, Myszor M, Gupta S, Tait C, Bloom SR. Regional differences in concentrations of regulatory peptides in human colon mucosal biopsy. Dig Dis Sci 1989; 34:1193-8. [PMID: 2568900 DOI: 10.1007/bf01537267] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The study was undertaken to examine regional differences in the concentrations of five regulatory peptides in the human colonic mucosa. Biopsies were obtained during routine colonoscopy from 33 patients whose colonic mucosa was macroscopically and histologically normal. Regulatory peptides were extracted, and measured by specific radioimmunoassays. Concentrations of three peptides that are present predominantly in endocrine cells within colonic mucosa increased significantly towards the rectum: Mean concentrations of peptide YY, enteroglucagon, and somatostatin were about three times greater in the rectum than in the cecum. However, concentrations of two peptides that are present in mucosal nerve fibers diminished significantly towards the rectum: Mean rectal concentrations of vasoactive intestinal peptide and peptide histidine methionine were both about 0.6 of mean cecal concentrations. Concentrations of all five peptides were lower in biopsies taken from colonic polyps than in normal colonic mucosa. Regional differences in colonic mucosal concentrations of regulatory peptides probably reflect differences in the physiological functions of different parts of the colon.
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Bean AJ, Adrian TE, Modlin IM, Roth RH. Dopamine and neurotensin storage in colocalized and noncolocalized neuronal populations. J Pharmacol Exp Ther 1989; 249:681-7. [PMID: 2732943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The effects of reserpine on dopamine (DA) and neurotensin (NT) levels were studied in four different brain regions of the rat. Reserpine (0.5-5.0 mg/kg i.p., 6, 18, 48 and 72 hr) produced a dose- and time-dependent decrease in both DA and NT levels in the prefrontal cortex, a brain region innervated by a mixed DA/NT projection. The effect of reserpine was not mimicked by alpha-methylparatyrosine (200 mg/kg i.p.) pretreatment. Furthermore, the reserpine-induced decline in prefrontal cortex DA and NT levels occurred after gamma-butyrolactone (GBL)-induced inhibition of impulse flow (750 mg/kg i.p.). In contrast, in the nucleus accumbens and striatum, regions which contain colocalized (nucleus accumbens) and intrinsic (striatum and nucleus accumbens) neurotensin perikarya, reserpine produced declines in DA and increases in NT levels. alpha-Methylparatyrosine decreased striatal and nucleus accumbens DA levels without altering NT levels in these structures. GBL produced an increase in DA levels in the nucleus accumbens and striatum while decreasing nucleus accumbens and striatal NT levels. Reserpine attenuated the decline in nucleus accumbens and striatal NT levels produced by GBL. In the periaqueductal grey, a brain region densely innervated by NT which has a small population of DA perikarya, reserpine had no effect on NT levels. Because there is no known colocalization of DA and NT in the striatum, the increases in striatal NT levels after depletion of DA may indicate that striatal DA afferents control the release and/or synthesis of NT within NT cells in the striatum, thus leading to alterations in striatal tissue levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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Zdon MJ, Lewis JJ, Adrian TE, Modlin IM. Decreased parietal cell secretory capacity following vagotomy and pyloroplasty. J Surg Res 1989; 46:490-5. [PMID: 2716307 DOI: 10.1016/0022-4804(89)90166-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Although vagotomy reduces acid secretion in vivo, the effects of vagotomy at the level of the parietal cell are not known. In the present study we examined the in vitro secretory characteristics of parietal cells in rabbits 8 weeks following vagotomy compared to unoperated and sham-operated controls. Acid secretion was assessed by the uptake of [14C]aminopyrine (AP) in isolated gastric glands. Also, gastric fundus histology, mucosal thickness, parietal cell density, and gastric gland somatostatin content were examined. Basal AP uptake was decreased following vagotomy (8 +/- 0.4 pmole/mg dry wt) compared to controls (21 +/- 2) (P less than 0.001). Increase in AP uptake by the cholinergic agonist carbachol was unaffected after vagotomy (P greater than 0.5) suggesting intact muscarinic receptors and calcium second messenger system. Increase in AP uptake was significantly reduced following vagotomy by the cyclic AMP-mediated agonist histamine (P less than 0.05) and the cyclic AMP mimetic 8-bromo cyclic AMP (P less than 0.001) suggesting an alteration in the ability of the parietal cell to utilize cAMP following vagotomy. There were no discernible differences in histology, mucosal thickness, or parietal cell number in vagotomized animals compared to controls (P greater than 0.5). There was a significant increase in gastric gland somatostatin content following vagotomy (37 +/- 10 fmole/mg dry wt) compared to control (14 +/- 1.5) (P = 0.025). These results suggest that there is a decrease in the capacity of parietal cells to secrete acid following vagotomy. In addition, the decrease in cAMP utilization following vagotomy suggests that the cAMP second messenger system is dependent, at least in part, on an intact vagus nerve.
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Modlin IM, Bilchik AJ, Zucker KA, Adrian TE, Sussman J, Graham SM. Cholecystokinin augmentation of 'surgical' pancreatitis. Benefits of receptor blockade. ARCHIVES OF SURGERY (CHICAGO, ILL. : 1960) 1989; 124:574-8. [PMID: 2469410 DOI: 10.1001/archsurg.1989.01410050064013] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The management of acute pancreatitis has not changed appreciably throughout several decades. Recent evidence has suggested that cholecystokinin (CCK) may play an important role in pancreatic disease. Investigations into the precise role of CCK in acute pancreatitis have been hampered by the lack of a specific CCK receptor antagonist. Using a newly described, highly potent and specific CCK receptor antagonist, L-364,718, the effect of CCK in two models of acute "surgical" pancreatitis was examined: (1) the bile salt ductal perfusion model in the rat and (2) a traumatic model in the guinea pig. At a suboptimal dose for pancreatic enzyme secretion (25 pmol/kg/h), CCK was found to potentiate the severity of the ensuing pancreatitis in both models. Continuous CCK receptor blockade with L-364,718 (25 nmol/kg/h) improved biochemical, morphologic, and survival indexes. This study suggests that physiologic levels of CCK play an important permissive role in the evolution of acute pancreatitis. The use of L-364,718 as an investigative probe or therapeutic tool for acute pancreatitis is worthy of further consideration.
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Ferri GL, Adrian TE, Soimero L, Blank M, Cavalli D, Biliotti G, Polak JM, Bloom SR. Intramural distribution of immunoreactive vasoactive intestinal polypeptide (VIP), substance P, somatostatin and mammalian bombesin in the oesophago-gastro-pyloric region of the human gut. Cell Tissue Res 1989; 256:191-7. [PMID: 2469539 DOI: 10.1007/bf00224734] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The intramural distribution of vasoactive intestinal polypeptide (VIP), substance P, somatostatin and mammalian bombesin was studied in the oesophago-gastro-pyloric region of the human gut. At each of 21 sampling sites encompassing this entire area, the gut wall was separated into mucosa, submucosa and muscularis externa, and extracted for radioimmunoassay. VIP levels in the mucosa were very high in the proximal oesophagus (1231 +/- 174 pmol/g, mean +/- SEM) and showed varied, but generally decreasing concentrations towards the stomach, followed by a clear-cut increase across the pyloric canal (distal antrum: 73 +/- 16 pmol/g, proximal duodenum: 366 +/- 62 pmol/g); consistent levels were found in submucosa and muscle (200-400 pmol/g) at most sites, the stomach again showing lower concentrations. By contrast, substance P was present in small amounts as far as the proximal stomach, but sharply increased across the pyloric canal, especially in mucosa and submucosa (distal antrum: 20 +/- 6.5 and 5.5 +/- 1.3 pmol/g; proximal duodenum: 62 +/- 8.5 and 34 +/- 11 pmol/g, respectively). Somatostatin concentrations were very low in the mucosa of the oesophagus and stepwise increased in the cardiac, mid-gastric and pyloric mucosa (cardia: 224 +/- 72 pmol/g; distal antrum: 513 +/- 152 pmol/g; proximal duodenum: 1013 +/- 113 pmol/g); concentrations in the submucosa and muscularis were generally low, with the exception of antrum and duodenum. Mammalian bombesin was comparatively well represented throughout the oesophageal muscularis (5-8 pmol/g), but most abundant in the stomach in all layers (oxyntic mucosa: 24 +/- 2.7 pmol/g; submucosa: 20 +/- 5.7 pmol/g; muscle: 28 +/- 5.0 pmol/g).(ABSTRACT TRUNCATED AT 250 WORDS)
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Zucker KA, Longo WE, Modlin IM, Bilchik AJ, Adrian TE. Malignant diathesis from jejunal-ileal carcinoids. Am J Gastroenterol 1989; 84:182-6. [PMID: 2644819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A facet of carcinoid tumors often not recognized is their close association with other, noncarcinoid malignancies. The clinical course of two patients with multiple ileal-jejunal carcinoids and multiple other noncarcinoid malignancies is described. These patients were found to have elevated circulating levels of gastrin, bombesin, glucagon, enteroglucagon, pancreatic polypeptide, and peptide tyrosine tyrosine. These regulatory peptides have been demonstrated to promote trophic effects on the gastrointestinal tract as well as malignant tumors. We propose that the release of these bioactive hormones into the portal and systemic circulation by carcinoid tumors may play some role in their association with these multiple second tumors.
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Basson MD, Fielding LP, Bilchik AJ, Zucker KA, Ballantyne GH, Sussman J, Adrian TE, Modlin IM. Does vasoactive intestinal polypeptide mediate the pathophysiology of bowel obstruction? Am J Surg 1989; 157:109-15. [PMID: 2910115 DOI: 10.1016/0002-9610(89)90429-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We hypothesized that bioactive peptides might be released into the portal circulation and mediate pathophysiologic alterations accompanying small bowel obstruction. We studied this question in a subacute canine small bowel obstruction model using 50 percent diameter occlusion. Control animals underwent sham laparotomy. Vasoactive intestinal peptide (VIP), peptide YY, and gastrin were measured in portal and systemic plasma by specific radioimmunoassays at 24-hour intervals as the obstruction progressed to completion over 5 days. All peptides in both groups demonstrated portal and peripheral gradients. In control dogs, peptide concentrations did not change postoperatively but VIP increased markedly in obstructed dogs, demonstrating a median portal level of 95 pmol/liter at 96 hours compared with 31.5 pmol/liter in control animals. These portal VIP levels are known to cause hypersecretion and splanchnic vasodilation in experimental models. The release of vasoactive compounds such as VIP may mediate local pathophysiology in human small bowel obstruction. A similar explanation of the systemic effects is consistent with the known cardiopulmonary bioactivity of VIP.
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Domschke S, Bloom SR, Adrian TE, Lux G, Bryant MG, Domschke W. Coeliac sprue: abnormalities of the hormone profile of gastroduodenal mucosa. SCANDINAVIAN JOURNAL OF GASTROENTEROLOGY. SUPPLEMENT 1989; 167:86-9. [PMID: 2482534 DOI: 10.3109/00365528909091319] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
To further characterize coeliac sprue, the hormonal content of routine endoscopic biopsies of gastroduodenal mucosa was estimated in 5 coeliac sprue patients and in 8 volunteers without upper gastrointestinal disease. Levels of cholecystokinin-like immunoreactivity tended to be lower in duodenal mucosa of coeliac sprue patients, while the mucosal map of GIP and somatostatin exhibited no peculiar profile. Gastrin was markedly elevated in the antral mucosa of coeliac sprue patients (3013 +/- 760 versus 1048 +/- 392 pmol/g), while basal plasma gastrin was normal. The mucosal VIP content of the descending duodenum was significantly higher in coeliacs than in controls (409 +/- 161 versus 81 +/- 16 pmol/g) and tended to be increased also in the remaining upper small intestine. This rise may be a reaction to mucosal irritation and a reason for enhanced fluid secretion. Even in antral mucosa of coeliac sprue patients, VIP levels were elevated when compared to controls (82 +/- 14 versus 40 +/- 8 pmol/g) and may have some impact, e.g. on local mucosal blood flow or mucus secretion. The mucosal concentration of another putative neurotransmitter, substance P, also showed a tendency to be raised in the mucosa of upper small intestine of coeliac sprue patients.
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Domschke S, Adrian TE, Bloom SR, Lux G, Domschke W. Gut hormone release by intraduodenal stimulation in duodenal ulcer patients. SCANDINAVIAN JOURNAL OF GASTROENTEROLOGY. SUPPLEMENT 1989; 167:60-4. [PMID: 2617172 DOI: 10.3109/00365528909091314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
After an overnight fast, plasma levels of gut peptide hormones were determined before and after intraduodenal stimulation (IDS) with glucose and citric acid in 8 patients with a recent endoscopically proved duodenal ulcer (DU) attack and in 8 healthy volunteers. The DU patients had a hyperacidic mean BAO of 6.6 and an average PAO of 41.8 mEq/h. In DU, basal secretin levels were similar to those in controls, and after IDS secretin release was not impaired. There was no defect of VIP liberation or of the neurotensin response (basal 21 +/- 7 vs 16 +/- 3, after IDS 68 +/- 28 vs 35 +/- 5 pmol/l) which could account for gastric acid hypersecretion. Although fasting GIP levels were significantly lower than in controls (16 +/- 2.5 vs 25 +/- 1.4 pmol/l), they did not correlate negatively with BAO. In contrast to former studies with oral test meals, integrated GIP release was rather reduced after IDS. Basal plasma levels of gastrin were significantly lower in DU (4.0 +/- 0.4 vs 12 +/- 2 pmol/l) and were inversely related to BAO (r = -0.82, p less than 0.02). From the present data, there is insufficient evidence for abnormal plasma levels of gut hormones as major etiologic factors for basal hyperchlorhydria in ordinary DU disease.
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Lewis JJ, Zdon MJ, Adrian TE, Modlin IM. Pancreastatin: a novel peptide inhibitor of parietal cell secretion. Surgery 1988; 104:1031-6. [PMID: 2904181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Pancreastatin is a recently identified 49-amino-acid peptide found in gastrointestinal tract and gastric mucosa. Its biologic effects on gastric function are unknown. The aim of this study was to determine the effects of pancreastatin [33-49] (the synthetic C-terminal fragment) on acid secretion and somatostatin release in vitro. Isolated rabbit gastric glands were prepared by means of collagenase digestion. Acid secretion was assessed indirectly with use of 14C-aminopyrine (AP) uptake by glands, and somatostatin release from D cells was measured with radioimmunoassay. Pancreastatin alone (10(-10) to 10(-6) mol/L) had no effect on 14C-AP uptake compared with unstimulated glands. In contrast, pancreastatin inhibited with histamine-(10(-6), 10(-5) mol/L; p less than 0.005) and carbachol-(10(-5), 10(-4) mol/L; p less than 0.001) stimulated 14C-AP uptake in a dose-dependent manner. Neither forskolin-(10(-6), 10(-4) mol/L; p greater than 0.50) or 8-Br-cAMP-(10(-5), 10(-4) mol/L; p greater than 0.30) stimulated 14C-AP uptake were influenced by pancreastatin. Pancreastatin had no effect on somatostatin release from glands. These data suggest that pancreastatin probably acts at receptor or membrane level, inhibiting both histamine- and carbachol-stimulated 14C-AP uptake. These effects are not mediated by D cell somatostatin release. It is possible that pancreastatin acts as a paracrine or endocrine inhibitory regulator of parietal cell secretion.
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Füessl HS, Adrian TE, Uttenthal LO, Bloom SR. Peptide YY in diabetics treated chronically with an intestinal glucosidase inhibitor. KLINISCHE WOCHENSCHRIFT 1988; 66:985-9. [PMID: 3054280 DOI: 10.1007/bf01738114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Peptide YY (PYY) is a recently discovered peptide found in the distal ileum and colon. It circulates in plasma and concentrations rise in malabsorptive conditions. The potential of PYY as an indicator of impaired carbohydrate digestion was studied in a pharmacological model of intestinal glucosidase inhibition. Thirteen type-2 diabetics on long-term treatment with the alpha-glucosidase inhibitor acarbose (3 x 100 mg per day) had test meals with and without acarbose 100 mg before and after the treatment period (mean 46 weeks), a test meal with acarbose after 20 weeks of continuous treatment and a final test meal without acarbose 6 weeks after cessation of treatment. Without acarbose mean plasma PYY concentrations rose from a mean basal value of 11.5 +/- 2.9 pmol/l to 19.5 +/- 3.9 pmol/l 120 min postprandially (P less than 0.01). Acarbose treatment did not effect basal plasma PYY concentrations but significantly enhanced food stimulated PYY concentrations acutely, at 20 weeks and at the final treatment test meal. Mean incremental integrated plasma responses (area under curve) rose by 183%, 184% and 169%, respectively (P less than 0.05). After cessation of treatment postprandial responses returned to pretreatment values within 6 weeks. Conversely, the integrated incremetal postprandial plasma responses of glucose and insulin were reversibly reduced by acarbose to 58% +/- 9% and 60% +/- 10% of controls, respectively. Self-assesed side effects of flatulence and more frequent bowel action showed no regular relationship to the PYY response. PYY seems to act as an indicator of the increased carbohydrate load to the distal intestine even in the absence of clinical symptoms. It may contribute to the hypoglycaemic effect of alpha-glucosidase inhibitors by slowing down intestinal transit.
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Domschke S, Bloom SR, Adrian TE, Lux G, Domschke W. Chronic pancreatitis and diabetes mellitus: plasma and gastroduodenal mucosal profiles of regulatory peptides (gastrin, motilin, secretin, cholecystokinin, gastric inhibitory polypeptide, somatostatin, VIP, substance P, pancreatic polypeptide, glucagon, enteroglucagon, neurotensin). HEPATO-GASTROENTEROLOGY 1988; 35:229-37. [PMID: 2465985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A disturbed intraduodenal milieu and pancreatic scarring in advanced chronic pancreatitis (CP) may lead to changes of gut and pancreatic hormones. In the present study, the gastroduodenal mucosal content of several regulatory peptides was determined in 8 patients with severe calcific CP and 8 healthy volunteers. In addition, hormone release into the bloodstream was estimated after intraduodenal acid/glucose stimulation in the control subjects and 8 CP patients each with or without secondary diabetes mellitus (DM), and in 8 patients with juvenile DM, so that disturbed gut hormone release could be attributed either to CP or DM. While VIP release into the circulation was similar in all participants, mucosal levels of VIP and substance P were significantly elevated in the duodenal bulb and descending duodenum of CP patients. The somatostatin content of gastroduodenal mucosa in CP was at least as high as in normals. Gastrin was significantly more abundant only in the duodenal bulb of CP patients, while plasma gastrin was normal. Duodenal CCK concentrations tended to be elevated in the duodenal bulb, but not significantly. The release of secretin seemed to be higher in type-1 diabetics than in CP patients. The mucosal pattern of GIP was nearly identical in CP patients and controls. Compatible with this finding, the GIP release did not show any peculiarities in CP with or without DM or in DM. Basal and stimulated plasma levels of motilin were abnormally high in CP. Pancreatic polypeptide plasma levels were normal in DM, but significantly reduced in CP, especially in CP with DM. Fasting PP and stimulated pancreatic enzyme outputs were linearly related.(ABSTRACT TRUNCATED AT 250 WORDS)
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Salmenperä L, Perheentupa J, Siimes MA, Adrian TE, Bloom SR, Aynsley-Green A. Effects of feeding regimen on blood glucose levels and plasma concentrations of pancreatic hormones and gut regulatory peptides at 9 months of age: comparison between infants fed with milk formula and infants exclusively breast-fed from birth. J Pediatr Gastroenterol Nutr 1988; 7:651-6. [PMID: 3183869 DOI: 10.1097/00005176-198809000-00005] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Little is known about the development of gut endocrine responses to food intake in infants after the first postnatal month. To examine this question and to ascertain whether the mode of feeding from birth affects postprandial endocrine changes, blood glucose levels and the plasma concentrations of 11 regulatory peptides were measured at 9 months of age before and after a breast feeding in 13 exclusively breast-fed infants and before and after a formula feeding in 7 infants weaned during the first 3 months of life. In the prefeeding concentrations of these substances, no significant differences were found between the two groups, with the possible exception of the plasma concentration of pancreatic polypeptide (p = 0.06). Postprandially, the responses were significantly smaller in the breast-fed infants, whose plasma concentrations of insulin, gastric inhibitory polypeptide, pancreatic polypeptide, and cholecystokinin were lower than in the formula-fed infants. In addition, the overall level of the insulin-glucagon ratio was lower (p = 0.03) in the breast-fed infants. A difference in the opposite direction was observed for plasma gastrin levels. No significant differences appeared between the groups for blood glucose, or plasma glucagon, vasoactive intestinal polypeptide, motilin, enteroglucagon, secretin, or neurotensin concentrations after feeding. It is concluded that at 9 months of age, the gut regulatory responses to milk feeding are of lower magnitude than during the neonatal period, but even at this age the response patterns still depend on the mode of feeding.
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Spiller RC, Trotman IF, Adrian TE, Bloom SR, Misiewicz JJ, Silk DB. Further characterisation of the 'ileal brake' reflex in man--effect of ileal infusion of partial digests of fat, protein, and starch on jejunal motility and release of neurotensin, enteroglucagon, and peptide YY. Gut 1988; 29:1042-51. [PMID: 3410330 PMCID: PMC1433910 DOI: 10.1136/gut.29.8.1042] [Citation(s) in RCA: 206] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Previous studies have shown that ileal infusion of partially digested triglyceride inhibits jejunal motility. The partial digest used in those studies contained a mixture of glycerol, free fatty acid, mono-, di-, and triglycerides. In Part I of the present study we have separately infused emulsions containing either glycerol 3.1 g (n = 6), oleic acid 9.6 g (n = 6), triolein 10 g (n = 12), or medium chain triglycerides 10 g (n = 6) into the ileum and have recorded the effect this has on jejunal motility. Five further subjects received infusions of partial hydrolysates of corn starch 10 g and lactalbumin 7 g. Marked inhibition of jejunal pressure wave activity was seen after all three lipid infusions, per cent activity falling from a control of 37.7 (7.7) to 6.2 (2.1) and 22.4 (8.2)% 30 min after completing the oleic acid and triolein infusions respectively, and from a control value of 39.5 (4.1) to 17.7 (4.7) after MCTs (all p less than 0.05). No significant fall occurred after infusion of glycerol, protein or carbohydrate. All three lipid infusions raised plasma concentrations of neurotensin, enteroglucagon and peptide YY equally effectively, although only the rise in peptide YY correlated significantly with the inhibition of jejunal pressure wave activity (r = 0.80, n = 6, p less than 0.05). In Part II of this study six subjects received a 3 ml/min jejunal infusion of an isotonic carbohydrate saline solution followed after three hours by a similar infusion of a partial digest of lipid. During each infusion flow and transit time was measured by marker and dye dilution. Jejunal infusion of the carbohydrate-saline solution was associated with low jejunal flow, 4.7 (1.0) ml/min and a mean transit time through the 50 cm study segment of 36.5 (7.1) min. By contrast jejunal infusion of partially digested triglyceride was associated with a markedly increased flow, 9.0 (1.2) ml/min, a fall in mean transit time to 20.3 (2.6) min and significant rises in pancreaticobiliary secretions. Jejunal triglyceride also increased the incidence of prolonged high amplitude jejunal pressure waves in four of six subjects. These studies suggest that there are important differences in the jejunal response to ileal versus jejunal lipid. While long and median chain free fatty acids infused into the ileum exert an inhibitory effect on jejunal motility, when infused directly into the jejunum partially digested triglyceride accelerates transit, increases jejunal flow and subtly alters the pattern of jejunal contractions.
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Abstract
In vivo observations have suggested that acid secretion may potentiate pepsinogen release. We measured pepsinogen and acid secretion by guinea pig fundic mucosal sheets stimulated by 10(-4) M histamine, 10(-8) and 10(-9) M cholecystokinin, and 3 x 10(-7) M carbamylcholine and then investigated the effects of 10(-4) M omeprazole on basal, carbachol-stimulated, and cholecystokinin-stimulated secretion. Histamine increased basal acid secretion fivefold (p less than 0.01) without altering pepsinogen secretion. Cholecystokinin did not stimulate acid secretion but increased pepsinogen secretion by factors of 23.1 at 10(-8) M and 9.1 at 10(-9) M (both p less than 0.01). The combination of 10(-4) M histamine and 10(-9) M cholecystokinin increased acid secretion 3.5-fold and pepsinogen secretion 6.4-fold, statistically equivalent to the sum of the effects of histamine and cholecystokinin alone. Carbachol increased acid secretion and pepsinogen secretion by factors of 4.0 and 10.9, respectively (both p less than 0.01). Pretreatment with 10(-4) M omeprazole abolished basal and carbachol-stimulated acid secretion. However, pepsinogen secretion was unaffected (p greater than 0.05). Furthermore, omeprazole-treated tissues increased pepsinogen secretion by factors of 10.0 with 3 x 10(-7) M carbachol and 9.1 with 10(-9) M cholecystokinin (both p less than 0.01). Thus, basal and secretagogue-stimulated pepsinogen secretion appear independent of acid secretion in intact guinea pig mucosa.
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Zucker KA, Adrian TE, Ballantyne GH, Modlin IM. Prostaglandin E analogue inhibition of intrinsic factor release. Scand J Gastroenterol 1988; 23:650-4. [PMID: 3140367 DOI: 10.3109/00365528809093926] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In many mammalian species (including humans) the parietal cell secretes both acid and intrinsic factor (IF). The aim of this study was to examine the direct effect of prostaglandin E analogues on basal and stimulated IF release in isolated, enriched rabbit parietal cells. The effects of graded concentrations (10(-12) to 10(-6) M) of 16,16-dimethyl prostaglandin E2 (DMPGE2) and 16-methyl,16-hydroxyl prostaglandin E1 (misoprostol) on submaximal histamine-stimulated (10(-6) M) secretion were tested. Both analogues failed to alter basal release of IF or aminopyrine accumulation (indirect measure of acid secretion). Increasing concentrations of DMPGE2 resulted in a dose-dependent inhibition of IF release (22 +/- 8% decrease at 10(-9) M; p less than 0.05) and a maximal effective response at 10(-7) M (54 +/- 9%; p less than 0.005). Dose-dependent inhibition of IF secretion was also observed with increasing concentrations of misoprostol, with a 22 +/- 7% decrease at 10(-9) M (p less than 0.05) and maximal effective inhibition at 10(-6) M (47 +/- 8%; p less than 0.01). Misoprostol and DMPGE2 inhibition of acid secretion paralleled IF release. Prostaglandin analogues appear to block IF release potently in histamine-stimulated parietal cells.
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Oddsdottir M, Goldenring JR, Adrian TE, Zdon MJ, Zucker KA, Modlin IM. Identification and characterization of a cytosolic 30 kDa histamine stimulated phosphoprotein in parietal cell cytosol. Biochem Biophys Res Commun 1988; 154:489-96. [PMID: 2840899 DOI: 10.1016/0006-291x(88)90166-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Histamine stimulated acid secretion is mediated by an increase in intracellular cAMP. Cytosolic protein phosphorylation stimulated by histamine was investigated in isolated rabbit parietal cells. Histamine stimulated the phosphorylation of a 30 kDa phosphoprotein with an isoelectric point of 5.6. Cimetidine completely inhibited histamine-stimulated pp30 phosphorylation. However, omeprazole had no effect on the phosphorylation of pp30. Forskolin and 8-bromo-cAMP also stimulated the phosphorylation of pp30. The results suggest that pp30 is a histamine-stimulated, cAMP-dependently phosphorylated protein substrate in parietal cell cytosol.
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Nicholls CD, Lee DL, Adrian TE, Bloom SR, Care AD. Hypergastrinaemia of sheep infected with Haemonchus contortus. Res Vet Sci 1988; 45:124-6. [PMID: 3222544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Radioimmunoassay of plasma gastrin has shown that a hypergastrinaemia occurs in yearling sheep, after infection with 10(6) infective third stage larvae of Haemonchus contortus. Plasma gastrin concentrations began to rise two to four days after infection, that is, at about the same time as, or slightly before, the abomasal pH was observed to increase.
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Ferri GL, Adrian TE, Allen JM, Soimero L, Cancellieri A, Yeats JC, Blank M, Polak JM, Bloom SR. Intramural distribution of regulatory peptides in the sigmoid-recto-anal region of the human gut. Gut 1988; 29:762-8. [PMID: 2454876 PMCID: PMC1433738 DOI: 10.1136/gut.29.6.762] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The distribution of regulatory peptides was studied in the separated mucosa, submucosa and muscularis externa taken at 10 sampling sites encompassing the whole human sigmoid colon (five sites), rectum (two sites), and anal canal (three sites). Consistently high concentrations of VIP were measured in the muscle layer at most sites (proximal sigmoid: 286 (16) pmol/g, upper rectum: 269 (17), a moderate decrease being found in the distal smooth sphincter (151 (30) pmol/g). Values are expressed as mean (SE). Conversely, substance P concentrations showed an obvious decline in the recto-anal muscle (mid sigmoid: 19 (2.0) pmol/g, distal rectum: 7.1 (1.3), upper anal canal: 1.6 (0.6)). Somatostatin was mainly present in the sigmoid mucosa and submucosa (37 (9.3) and 15 (3.5) pmol/g, respectively) and showed low, but consistent concentrations in the muscle (mid sigmoid: 2.2 (0.7) pmol/g, upper anal canal: 1.5 (0.8]. Starting in the distal sigmoid colon, a distinct peak of tissue NPY was revealed, which was most striking in the muscle (of mid sigmoid: 16 (3.9) pmol/g, upper rectum: 47 (7.8), anal sphincter: 58 (14)). Peptide YY was confined to the mucosa and showed an earlier peak (upper sigmoid: 709 (186) pmol/g, mid-distal sigmoid: 1965 (484)). A clear differential distribution of regulatory peptides was thus shown in the region studied. A possible role is suggested for NPY and VIP containing nerves in the effector control of the human internal anal sphincter.
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Zdon MJ, Adrian TE, Modlin IM. Gastric somatostatin release: evidence for direct mediation by calcitonin gene-related peptide and vasoactive intestinal peptide. J Surg Res 1988; 44:680-6. [PMID: 2898038 DOI: 10.1016/0022-4804(88)90100-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
It has previously been demonstrated that somatostatin (SRIF) directly inhibits parietal cell secretion. However, the significance of SRIF as a paracrine agent and mechanisms of local gastric SRIF release are not clear. Vasoactive intestinal peptide (VIP) and calcitonin gene-related peptide (CGRP) are neuropeptides which have been localized in the gastric fundus and have been demonstrated to inhibit gastric acid secretion in vivo. The present study examines the hypothesis that CGRP and VIP act via the release of gastric fundic SRIF. The study utilized rabbit isolated gastric glands prepared by collagenase digestion. Glands were incubated alone, or with 10(-10)-10(-6) M CGRP or 10(-10)-10(-6) M VIP for 30 min. Supernatant SRIF was measured using a specific radioimmunoassay. Unstimulated SRIF release was 101 +/- 16 fmole/ml. CGRP (10(-7) and 10(-6) M) and VIP (10(-7) and 10(-6) M) resulted in significant SRIF release. The maximum release of SRIF by CGRP (506 +/- 113 fmole/ml) was significantly greater than that by VIP (293 +/- 33 fmole/ml) (P less than 0.05). However, both these concentrations of SRIF are comparable to the ID50 concentration (4.5 X 10(-10) M) for SRIF inhibition of acid secretion by isolated parietal cells as assessed by [14C]aminopyrine accumulation. These results are consistent with the hypothesis that CGRP and VIP inhibition of acid secretion may be mediated, at least in part, by the local release of SRIF from the gastric fundus. These data further support the significance of paracrine interactions in the modulation of cellular secretory function.
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186
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Adrian TE, Ballantyne GH, Zucker KA, Zdon MJ, Tierney R, Modlin IM. Lack of peptide YY immunoreactivity in adenomatous colonic polyps: evidence in favor of an adenoma-carcinoma sequence. J Surg Res 1988; 44:561-5. [PMID: 3374119 DOI: 10.1016/0022-4804(88)90162-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The aim of endoscopic polypectomy is to prevent colorectal cancer, as it is assumed that most, if not all, large bowel cancers are derived from adenomatous polyps. While it is now recognized that colonic endocrine cells, like other mucosal epithelial cells, have an endodermal origin, they are relatively sparse components of large bowel tumors. Peptide YY (PYY) is the most abundant endocrine regulatory peptide localized to the distal bowel. Endocrine cells, like the other cells of the mucosal epithelia, are derived from a common stem cell in the base of the crypts. The presence of endocrine peptides may thus be viewed as a marker for cellular differentiation in the gut. PYY was therefore measured in colonic carcinomas and adenomatous polyps, as its absence would be evidence in favor of genetic alterations in epithelial stem cell maturation. PYY concentrations in extracts of surgically removed colonic carcinomas (n = 22) from all regions were very low compared with those of adjacent normal bowel. Similarly, PYY concentrations in extracts of polyps (n = 39) obtained during endoscopic polypectomy were also very low when compared with those of adjacent normal mucosa. These varied between 1 and 11% of the normal epithelial content, depending upon the region. Low PYY levels appeared to reflect the malignant potential of these lesions: highest in tubular polyps, lower in villous polyps, and lowest in carcinomas. The very low concentrations of PYY in adenomatous polyps, like those of colonic cancer, are consistent with epithelial dysplasia and the incomplete formation of mucosal endocrine cells. These findings support the hypothesis of an adenoma to carcinoma sequence in colonic cancer.
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187
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Basson MD, Zucker KA, Adrian TE, Zdon MJ, Ballantyne GH, Modlin IM. Pepsin release by prostaglandin E1 analogue. A potential therapeutic problem. ARCHIVES OF SURGERY (CHICAGO, ILL. : 1960) 1988; 123:431-3. [PMID: 3126724 DOI: 10.1001/archsurg.1988.01400280037007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Prostaglandins Inhibit gastric acid secretion and are independently "cytoprotective" for gastric mucosa. They are currently under clinical Investigation for the treatment of peptic ulcers. The effects of the prostaglandin E1 analogue misoprostol on pepsinogen and acid secretion were tested in isolated rabbit gastric glands and enriched parietal cells. Pepsinogen concentrations were measured by iodine 125-labeled albumin digestion and acid secretion indirectly by carbon 14-tagged aminopyrine uptake. Misoprostol inhibited histamine-stimulated acid secretion in parietal cells with 50% inhibition at 10(-9) mol/L and maximally (78% inhibition) at 10(-7) mol/L. In contrast, however, misoprostol strongly stimulated pepsinogen secretion by gastric glands with a half-maximal effect at 10(-8) mol/L and maximal stimulation of 227% at 10(-6) mol/L. It is possible that this release of pepsin could compromise the action of prostaglandins in promoting ulcer healing.
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188
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Modlin IM, Zucker KA, Zdon MJ, Sussman J, Adrian TE. Characteristics of the spontaneous gastric endocrine tumor of mastomys. J Surg Res 1988; 44:205-15. [PMID: 3343820 DOI: 10.1016/0022-4804(88)90049-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mastomys is a rodent which has been reported to develop spontaneous antral endocrine tumors with acid hypersecretion and duodenal ulceration. This study documents the establishment of a breeding colony and the characterization of the tumors and their possible secretagogues. Parietal cell secretory characteristics were studied using isolated gastric glands (IGG) of both normal (n = 5) and tumor-bearing animals. Tumors (n = 6) and control gastric tissue samples were examined by light transmission microscopy and immunohistochemistry. Gastrin was measured by radioimmunoassay in both plasma and tissue. IGG were prepared by collagenase dispersion and acid sequestration assessed by [14C]AP accumulation. Secretory mechanisms of this species were identified by establishment of a histamine dose-response curve and use of 8-bromo-cAMP. Receptor and proton pump inhibitions were assessed using cimetidine (10(-5)M) and the H/K ATPase inhibitor omeprazole (10(-5]. Both reduced [14C]AP accumulation significantly (P less than 0.05). 8-Bromo-cAMP and histamine significantly stimulated [14C]AP accumulation (P less than 0.05). Although parietal cells were substantially increased in tumor animals as compared to controls, the physiological parameters of acid secretion appeared normal in both and were comparable to other species which have been studied. Tumors were Grimelius positive and contained diffuse electron-dense granules. Immunohistochemistry was negative for gastrin, bombesin, serotonin, neuron-specific enolase, calcitonin, and pancreatic polypeptide. Tumor histamine-like immunoreactivity was, however, positive. Normal stomach contained 1001 +/- 185 compared to less than 0.5 pmole/g gastrin in tumors. Plasma gastrin was normal in both groups (29 +/- 5) as compared to 26 +/- 8 pmole/liter. This study characterizes a spontaneous gastric endocrine tumor which is associated with apparent parietal cell hyperplasia and reports of increased acid secretion and duodenal ulceration. The observations are consistent with the elaboration by the tumor of a nongastrin acid-trophic secretagogue.
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189
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Zdon MJ, Zucker KA, Adrian TE, Modlin IM. Somatostatin analogue inhibition of isolated parietal cell secretion. Surgery 1987; 102:967-73. [PMID: 2891202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Somatostatin, somatotropin release-inhibiting factor (SRIF), is a regulatory peptide that has proved to directly inhibit parietal cell acid secretion. However, the therapeutic usefulness of SRIF has been limited by a brief plasma half-life. Several analogues of SRIF that are effective in suppressing acid secretion in vivo have been developed. This study was undertaken to compare the effects of SRIF and two analogues, SMS 201-995 and L-363,568, on in vitro acid secretion. We used isolated rabbit parietal cells prepared by collagenase digestion and counterflow elutriation. Acid secretion was assessed by the accumulation of 14C-aminopyrine within the cells. Two types of secretagogues were utilized: histamine (10(-6) mol/L), a membrane receptor agonist which acts by means of adenylate cyclase and cyclic AMP, and forskolin (10(-6) mol/L), a direct activator of adenylate cyclase. SRIF, SMS 201-995, and L-363,568 (10(-11) to 10(-7) mol/L) all significantly inhibited histamine-stimulated 14C-AP uptake (p less than 0.001). On a molar basis, SMS 201-995 was 10 times more potent and L-363,568 was 40 times more potent than SRIF. SRIF, SMS 201-995, and L-363,568 significantly inhibited forskolin-stimulated 14C-AP uptake (p less than 0.005). The inhibitory effects of SRIF and both analogues on forskolin-stimulated acid secretion was, however, significantly less than that observed with histamine (p less than 0.05). These results demonstrate increased in vitro potency of SRIF analogues compared with the native peptide. The data are consistent with the hypothesis that SRIF and its analogues function at more than one site within the parietal cell.
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190
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Cambria RP, Neville R, Ballantyne GH, Zdon MJ, Zucker KA, Adrian TE, Modlin IM. Somatostatin and analogs lack splanchnic vasoconstrictive effects in anesthetized pigs. J Surg Res 1987; 43:452-9. [PMID: 2890795 DOI: 10.1016/0022-4804(87)90104-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Due to an apparently selective vasoconstrictive effect on the splanchnic circulation, somatostatin (SRIF) has been advocated for the treatment of variceal hemorrhage. The present study was designed to compare and contrast the systemic and splanchnic hemodynamic effects of SRIF and two of its long-acting analogs (SMS 201,995 and L 363,568) with those of Pitressin. Anesthetized pigs were subjected to laparotomy for placement of an electromagnetic flowmeter on the main trunk of the superior mesenteric artery (SMA). Systemic hemodynamic parameters of arterial blood pressure and cardiac output were monitored with thermodilution catheters. Portal venous blood was collected for measurement of plasma levels of SMS 201,995 and L 363,568 and for determination of gastrin levels during infusion of the latter analog. Experimental drugs were administered via an aortic cannula in a range (5-10 mg/kg bolus and 5-10 mg/kg/min continuous infusion) of dosages. At the higher dosages, SRIF, SMS 201,995, and L 363,568 decreased SMA blood flow (mean% +/- SD) 5.6 +/- 2.2, 1.6 +/- 4.4, and 8.0 +/- 3.8 after 10 min. None of the values achieved significance when compared to variation in baseline determinations. Pitressin (0.25 units, intravenously) produced a consistent and highly significant (P less than 0.001) reduction-in SMA flow after 5 min. Pharmacologic levels of SMS 201,995 and L 363,568 were reliably achieved in portal blood and the latter produced significant reduction (P less than 0.05) in portal venous levels of gastrin. SRIF and its long-acting analogs produced no significant splanchnic nor systemic hemodynamic effects in this model.
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191
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Fuessl HS, Williams G, Adrian TE, Bloom SR. Guar sprinkled on food: effect on glycaemic control, plasma lipids and gut hormones in non-insulin dependent diabetic patients. Diabet Med 1987; 4:463-8. [PMID: 2959439 DOI: 10.1111/j.1464-5491.1987.tb00910.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The effects of guar granules sprinkled over food on carbohydrate and lipid metabolism were studied in a double-blind cross-over trial in 18 patients with non-insulin-dependent diabetes mellitus (mean +/- SEM age 61.3 +/- 2.5 years). Five-gram guar granules (Guarem, Rybar Laboratories, Amersham, Bucks) were sprinkled over food at each main meal for 4 weeks, and during a 4-week placebo period (separated by a 2-week 'wash-out' period), 5 g wheat bran was taken in the same way. Diabetic treatment was not changed during the study. Mean fasting plasma glucose (FPG) concentration and glycosylated haemoglobin (HbA1) concentration after treatment were significantly lower than after the placebo period (FPG 8.29 +/- 0.47 vs 8.78 +/- 0.53 mmol/l, p less than 0.05; HbA1: 8.70 +/- 0.39 vs 9.09 +/- 0.39%, p less than 0.05). There was a 50% reduction in the incremental area under the postprandial glycaemic curve when guar was eaten with a standardized test meal. Total plasma cholesterol decreased from 5.79 +/- 0.29 to 5.19 +/- 0.22 mmol/l (p less than 0.05) after the guar treatment period. Guar ingestion reduced postprandial insulin and enteroglucagon responses, the latter significantly so, but had no apparent effect on gastric inhibitory polypeptide, pancreatic glucagon, gastrin, and pancreatic polypeptide.
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192
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Fuessl HS, Burrin JM, Williams G, Adrian TE, Bloom SR. The effect of a long-acting somatostatin analogue (SMS 201-995) on intermediary metabolism and gut hormones after a test meal in normal subjects. Aliment Pharmacol Ther 1987; 1:321-30. [PMID: 2979676 DOI: 10.1111/j.1365-2036.1987.tb00632.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
SMS 201-995 is an octapeptide analogue of somatostatin. The effect of a single subcutaneous (s.c.) injection of 50 micrograms SMS 201-995 on post-prandial intermediary metabolism was investigated in normal subjects. In spite of a long-lasting post-prandial suppression of insulin secretion, there were no significant changes in the plasma concentration of alanine, glycerol, 3-OH-butyrate or lactate. However, SMS 201-995 impairs carbohydrate tolerance, probably due to inhibition of insulin secretion. Basal and post-prandial plasma concentrations of the gut regulatory peptides pancreatic glucagon, motilin, pancreatic polypeptide, gastric inhibitory polypeptide, enteroglucagon, gastrin and peptide YY were suppressed up to 5 hours after subcutaneous administration of a single dose of SMS 201-995.
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193
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Zucker KA, Adrian TE, Zdon MJ, Ballantyne GH, Modlin IM. Asperlicin: a unique nonpeptide cholecystokinin antagonist. Surgery 1987; 102:163-70. [PMID: 2441481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The lack of a potent and specific cholecystokinin (CCK) receptor antagonist has greatly hampered studies of the role of CCK in controlling pancreatic growth, enzyme release, pancreatitis, and pancreatic carcinoma. Asperlicin, a newly described, CCK antagonist, has been shown to be a potent, competitive inhibitor of CCK-induced gallbladder and ileal muscle contraction. In this study, the effects of asperlicin on CCK- and carbachol-stimulated pancreatic enzyme release from dispersed guinea pig acini were investigated. Cholecystokinin caused a dose-dependent release of amylase and lipase. Half-maximal release of amylase (17.9% +/- 2.1%, mean +/- SEM, percent of total content) and lipase (27.3% +/- 2.1%) was seen with CCK 10(-11) mmol/L) both p less than 0.01). Asperlicin (10(-11) to 10(-4) mmol/L) caused a substantial inhibition (10(-11) mmol/L) of CCK-induced amylase release with a 50% maximal effective inhibitory dose of 10(-9) mmol/L (p less than 0.01) and maximum inhibition at 10(-6) mmol/L. Asperlicin was approximately 1000-fold more potent than proglumide (a previously described CCK receptor antagonist) which had a 50% effective inhibitory dose of 10(-6) mmol/L) and a maximal effect at 10(-4) mmol/L. Asperlicin (10(-10) to 10(-4) mmol/L) failed to alter carbachol-induced amylase release. Asperlicin is a new, potent CCK antagonist for pancreatic CCK receptors and should prove useful as an investigational tool. Such receptor antagonists may have therapeutic potential.
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194
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Adrian TE, Savage AP, Fuessl HS, Wolfe K, Besterman HS, Bloom SR. Release of peptide YY (PYY) after resection of small bowel, colon, or pancreas in man. Surgery 1987; 101:715-9. [PMID: 3589966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To investigate the possible role of peptide YY (PYY) in the adaptive changes that accompany enterectomy, plasma levels of this peptide were measured during breakfast in patients with resected small or large intestines and in controls. In 18 patients who had undergone partial ileal resection, basal PYY concentrations were greatly elevated when compared with controls (51.4 +/- 8.7 pmol/L versus 10.3 +/- 1.0; p less than 0.001) and the postprandial response was similarly increased. In contrast, PYY concentrations were low in 16 patients who had undergone colonic resection and ileostomy (fasting 7.1 +/- 0.7 pmol/L, p less than 0.01). In eight patients who had undergone pancreatectomies, basal and postprandial PYY levels were moderately increased (23.4 +/- 3.5 pmol/L; fasting p less than 0.001). PYY does not appear to have a role in the adaptive trophic response after small intestinal resection, but it may contribute to reduction of gastric secretion and gastrointestinal transit in these patients.
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195
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Zucker KA, Zdon MJ, Adrian TE, Ballantyne GH, Modlin IM. Prostaglandin inhibition of acid is cAMP dependent. J Surg Res 1987; 42:513-20. [PMID: 3035281 DOI: 10.1016/0022-4804(87)90026-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Prostaglandin E (PGE) potently inhibits acid secretion stimulated by histamine, but not by acetylcholine or gastrin, and is accompanied by decreased intracellular cAMP. Adenylate cyclase receptor systems are composed of three complex proteins: cell receptor, nucleotide binding protein, and the catalytic subunit. The exact mechanism of PGE interaction with this complex remains unclear and elucidation of this site of action is the purpose of this study. We utilized molecular probes directed at the various components of adenylate cyclase. Cholera toxin alters the stimulatory subunit of the nucleotide binding proteins (Ns), rendering it resistant to normal deactivation, whereas N-ethylmaleimide (NEM) blocks the inhibitory subunit (Ni). Forskolin acts as a direct activator of the catalytic subunit of adenylate cyclase and 8-bromo-cAMP acts as a cyclic AMP mimetic. We measured in vitro acid secretion in isolated parietal cells by the assessment of [14C]aminopyrine (AP) accumulation. The PGE1 analog (miso) and the PGE2 analog (DMPG) were incubated in graded doses (10(-11) to 10(-6) M) with histamine (10(-6) M). Miso (10(-7) M) reduced AP accumulation to 21 +/- 8% of histamine alone (100%) and DMPG (10(-6) M) reduced AP to 61 +/- 9% (P less than 0.005 for both). AP accumulation stimulated by 8-Br-cAMP (10(-6) M) and forskolin (10(-6) M) was not significantly affected by either PGE analog (P greater than 0.05) suggesting that the site of PGE interaction is proximal to the activation of the catalytic subunit.(ABSTRACT TRUNCATED AT 250 WORDS)
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Isaacs PE, Ladas S, Forgacs IC, Dowling RH, Ellam SV, Adrian TE, Bloom SR. Comparison of effects of ingested medium- and long-chain triglyceride on gallbladder volume and release of cholecystokinin and other gut peptides. Dig Dis Sci 1987; 32:481-6. [PMID: 3568934 DOI: 10.1007/bf01296030] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In a double-blind, crossover study of the effect of ingested medium-chain triglyceride (MCT) and long-chain triglyceride (LCT) in six normal subjects, the gallbladder did not contract after ingestion of MCT but instead had significantly increased in volume at 2 hr after the meal. Plasma cholecystokinin (CCK) increased after the MCT meal, but gastrin, motilin, pancreatic polypeptide (PP), and GIP were unaffected. The long-chain triglyceride meal evoked a brisk and sustained gallbladder contraction, higher levels of CCK, and a significant increase in plasma PP and GIP levels.
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197
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Adrian TE, Bacarese-Hamilton AJ, Smith HA, Chohan P, Manolas KJ, Bloom SR. Distribution and postprandial release of porcine peptide YY. J Endocrinol 1987; 113:11-4. [PMID: 3585220 DOI: 10.1677/joe.0.1130011] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Peptide YY (PYY), a thirty-six amino acid intestinal hormonal peptide with a tyrosine residue at each end (hence YY as Y represents tyrosine in the new peptide nomenclature), was found throughout the gastrointestinal tract of the pig. Concentrations were very low in the foregut (antrum, 3.4 +/- 0.3 pmol/g; duodenum, 1.1 +/- 1.5 pmol/g), higher in the distal small intestine (ileum, 100 +/- 13 pmol/g) and very high in the large bowel (descending colon, 270 +/- 45 pmol/g). Peptide YY was found to circulate in plasma and concentrations rose substantially in response to eating (fasting, 138 +/- 15 pmol/l; postprandial, 263 +/- 21 pmol/l; P less than 0.001). There was a small but significant portal/arterial gradient in postprandial PYY levels. More than 90% of the immunoreactive PYY in gut extracts eluted, on gel permeation chromatography, in an identical position to pure PYY standard, but small amounts of higher molecular weight material, possibly precursors, were detected. In contrast, plasma from fasting pigs contained a large proportion (60-70%) of these large molecular forms. These findings suggest that the putative pro-PYY may be cleared more slowly from the circulation than the 36 amino acid hormonal peptide. The high concentrations of immunoreactive PYY in the circulation of the young pig may reflect a species difference between pig and man or may indicate an important role for PYY in the developing animal.
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198
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Modlin IM, Oddsdottir M, Adrian TE, Zdon MJ, Zucker KA, Goldenring JR. A specific histamine-stimulated phosphoprotein in isolated parietal cells. J Surg Res 1987; 42:348-53. [PMID: 3033399 DOI: 10.1016/0022-4804(87)90168-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Histamine-stimulated phosphorylation was studied in isolated rabbit parietal cells. Secretion of acid, as assessed by aminopyrine uptake, was linear at 15 min of stimulation with histamine. By utilizing two dimensional gels, a specific 30,000-Da protein (pp30) was identified whose phosphorylation was prominently stimulated by histamine after 15 min of incubation. The pp30 protein displayed an isoelectric point of 6.0. Furthermore, cAMP-dependent pp30 phosphorylation could also be demonstrated in vitro in a preparation of parietal cell cytosol. The results suggest that pp30 may represent an important histamine-stimulated cAMP-dependent phosphoprotein involved in the initiation or maintenance of parietal cell secretion.
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199
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Ferri GL, Adrian TE, Ghatei MA, Soimero L, Rebecchi L, Biliotti G, Polak JM, Bloom SR. Intramural distribution of regulatory peptides in the human stomach and duodenum. HEPATO-GASTROENTEROLOGY 1987; 34:81-5. [PMID: 3596462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The distribution of regulatory peptides was studied by radioimmunoassay in the separated mucosa, submucosa and muscularis externa of the human oxyntic stomach, antrum and duodenum. Immunoreactive gastrin, secretin, gastric inhibitory polypeptide and motilin were virtually confined to the mucosa and duodenal submucosa, where endocrine cells are present. Only minor amounts of motilin and gastrin (3.2 +/- 0.5% and 4.3 +/- 0.8% of their total content, means + SEM, respectively) were found in the separated duodenal muscle. Somatostatin-, vasoactive intestinal polypeptide-, substance P-, and mammalian bombesin-like peptides showed distinct differential distributions in all layers. Substance P was low in the stomach and markedly increased in the duodenum, especially in the mucosa (fundus 0.8 +/- 0.2 pmol/g, duodenum 66 +/- 12). Vasoactive intestinal polypeptide and somatostatin, although well represented in the stomach, also increased in the duodenum in all layers of the wall (whole fundus 281 +/- 33 and 334 +/- 46 pmol/g, antrum 124 +/- 18 and 426 +/- 59, duodenum 507 +/- 99 and 1816 +/- 149, respectively). Mammalian bombesin immunoreactivity was comparatively abundant in the oxyntic stomach (mucosa 34 +/- 4.5 pmol/g, muscularis externa 29 +/- 4.8), less so in the antrum (6.3 +/- 1.5 and 11 +/- 3.2 pmol/g, respectively). Low concentrations of this peptide were measured in the duodenum, practically confined to the muscle (this layer 5.1 +/- 1.5 pmol/g, or 83 +/- 5.6% of the total content).
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200
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Savage AP, Matthews JL, Adrian TE, Ghatei MA, Cooke T, Bloom SR. Effect of a long-acting analogue of somatostatin, SMS 201-995, on the development of intestinal tumours in azoxymethane-treated rats. Carcinogenesis 1987; 8:561-3. [PMID: 2881630 DOI: 10.1093/carcin/8.4.561] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The effect of daily parenteral administration of a long-acting analogue of somatostatin (SMS 201-995) on the development of intestinal tumours and the rate of crypt cell proliferation in azoxymethane-treated rats has been studied. SMS 201-995 had no significant effect on the number of colonic tumours induced. In the duodenum, SMS 201-995 administration was associated with a change in the number of tumours from 1.4/rat in saline-treated animals to 2.4/rat in animals treated for the last third of the study and 2.8/rat in animals treated with SMS for the entire duration of the study (P less than 0.02). SMS had no significant effect on the rate of cell proliferation in the duodenum, ileum or colon. The inhibition of release of gastrointestinal trophic hormones by this analogue of somatostatin thus does not appear to reduce the number of tumours in the intestine of azoxymethane-treated rats.
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