Enhancement of pancreatic enzyme synthesis by pancreozymin

Ss, Ratnam; Wells, Herbert

doi:10.1152/ajplegacy.1967.213.1.215

Cited by 118 publications

(28 citation statements)

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“…Morphologic examination of pancreata revealed enlargement of acinar cells. They attributed the increases in weight to increases in protein and enzyme synthesis (30). Mayston These studies add another dimension to our understanding of the role of CCK-PZ in pancreatic function.…”

Section: Resultsmentioning

confidence: 99%

Hormonal Control of Pancreatic Growth

Mainz¹,

Black²,

Webster³

1973

J. Clin. Invest.

239

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A B S T R A C T Investigations have outlined pancreatic secretory and synthetic responses to gastrointestinal hormones. However, there is little information concerning hormonal influences on pancreatic growth.These studies were designed to examine effects of chronic administration of bethanechol and cholecystokinin-pancreozymin (CCK-PZ) on the pancreas. M\Iale albino rats were given saline, bethanechol, 6 mg/kg, or CCK-PZ, 20 U/kg, intraperitoneally twice daily and killed after 5 days. DNA was determined by the diphenylamine method using calf thymus DNA as a standard (20). RNA was determined by the orcinol method using ribose as a standard (21). Protein was determined by the biuret method using bovine serum albumin as the standard (22). Radioactivity was assayed in a Packard liquid scintillation counter (Packard Instrument Co., Inc., Downers Grove, Ill.) using a phosphor developed by Patterson and Greene (23). Fig. 1 shows rates of incorporation of ["C]thymidine into pancreatic DNA. Under these conditions of in vitro incubation, incorporation was near linear for 30, 60, 90, 120, and 150 min. Other investigators, using different tissues, have shown that thymidine nucleotide pools were small and that there was rapid equilibration between intracellular and extracellular thymidine pools (24). In addition, at concentrations of ["C]thymidine used in these experiments, no labeled ["C]thymidine triphosphate remained unincorporated in the cell (25). These observations were considered sufficient to validate the use of in vitro incubation of pancreas for short-term studies of DNA synthesis. A 90 min period of in vitro incubation was used for other experiments. RESULTS

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Section: Resultsmentioning

confidence: 99%

Hormonal Control of Pancreatic Growth

Mainz¹,

Black²,

Webster³

1973

J. Clin. Invest.

239

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“…Thus, the involvement of CCK seems to be a species-related phenomenon. Rothman & Wells (1967) first showed that treatment of rats with CCK caused an increase in pancreatic weight and enzyme content as welll as increased acinar cell size, suggesting acinar cell hypertrophy. Subsequent studies in rats (for review see Solomon, 1981;Folsch, 1984) have confirmed these observations and, in addition, have shown an increased content and rate of synthesis of DNA, suggesting hyperplasia to be a constant finding after chronic CCK treatment.…”

Section: Discussionmentioning

confidence: 99%

Effect of a new potent CCK antagonist, lorglumide, on caerulein‐ and bombesin‐induced pancreatic secretion and growth in the rat

Scarpignato

Varga

Dobronyi

et al. 1989

British J Pharmacology

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1 The effect of lorglumide, a new potent cholecystokinin (CCK) antagonist, on pancreatic secretion and growth induced by caerulein and bombesin was studied in the rat. 2 Pancreatic exocrine secretion was studied both in vitro (isolated and perfused pancreatic segments) and in vivo (anaesthetized animals with cannulation of the common bile duct) whereas the trophic effect was investiged after short-term (5 days) administration of the peptides and/or lorglumide. 3 Both caerulein and bombesin stimulated amylase release from in vitro pancreatic segments in a concentration-dependent manner. Although the efficacy of both peptides was virtually identical, the potency of caerulein was higher than that of bombesin. Lorglumide displaced the concentrationresponse curves to caerulein to the right without affecting the maximum response, suggesting a competitive antagonism. The Schild plot analysis of data gave a straight line with a slope not significantly different from unity. The calculated pA2 for lorglumide was 7.31 + 0.45. The antagonist, however, was completely ineffective when tested against bombesin-induced amylase release. 4 In vivo experiments confirmed results from in vitro studies since lorglumide (5 and I0mgkg 1) significantly reduced pancreatic exocrine secretion induced by caerulein without affecting the response to bombesin. 5 Administration of either peptide increased the weight of the pancreas, the total pancreatic protein and DNA, trypsin and amylase content. Lorglumide (10mgkg-1), administered together with caerulein, reduced the peptide-induced increase in pancreatic weight, protein and enzyme content. On the contrary, when lorglumide was given together with bombesin, all the parameters that were examined were not altered by concomitant administration of the antagonist. 6 These results have demonstrated the ability of lorglumide to antagonize the effects on the pancreas of a CCK-analogue, caerulein, and its inability to affect bombesin-induced pancreatic secretion and growth, suggesting that lorglumide is a potent and selective antagonist of CCK-receptors in the pancreas.

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“…This may explain why feeding starved rats and ferrets (Poort & Kramer, 1969) as well as acute caerulein stimulation of starved guinea-pigs did not produce a rapid increase of protein synthesis in the pancreas. In this respect it is interesting to recall that the possibility of pancreozymin playing a main role in the regulation of the synthesis of pancreatic digestive enzymes has been envisaged previously on the basis of indirect evidence (Rothman & Wells, 1967;Konijn, Guggenheim & Birk, 1969;Konijn, Birk & Guggenheim, 1970;Snook, 1969) and that gastrin, another hormone of the gut, having a chemical composition similar to pancreozymin, has been found to have a trophic action on the gastric and duodenal mucosae (Johnson, Aures & Yuen, 1969a;Johnson, Aures & Hakanson, 1969b).…”

Section: Discussionmentioning

confidence: 99%

“…Very few prolonged experiments, implying repeated stimulation of pancreatic secretion, have been reported (Rothman & Wells, 1967).…”

Section: Introductionmentioning

confidence: 99%

Effect of caerulein on protein synthesis and secretion in the guinea‐pig pancreas

Meldolesi¹

1970

British J Pharmacology

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Summary1. Caerulein produced a striking increase in the rate of secretion of the guineapig pancreas. When tested in vivo with pancreatic slices its optimal concentration was found to be 2-5 ng/ml. It is concluded (a) that in the guinea-pig pancreas, stimulation of enzyme secretion does not affect per se the rate of synthesis of digestive enzymes; and (b) that the increase of protein synthesis elicited by caerulein is critically dependent both on the nature of the segretagogue (that is, it is elicited by the polypeptide but not by a cholinergic drug) and on the experimental conditions (it is evident only in fasted animals after prolonged treatment).Introduction Numerous studies dealing with the effect of stimulation of enzyme secretion on the rate of protein synthesis in the pancreas have been reported

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Enhancement of pancreatic enzyme synthesis by pancreozymin

Cited by 118 publications

References 0 publications

Hormonal Control of Pancreatic Growth

Hormonal Control of Pancreatic Growth

Effect of a new potent CCK antagonist, lorglumide, on caerulein‐ and bombesin‐induced pancreatic secretion and growth in the rat

Effect of caerulein on protein synthesis and secretion in the guinea‐pig pancreas

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