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

Meldolesi, Jacopo

doi:10.1111/j.1476-5381.1970.tb10649.x

Cited by 32 publications

(8 citation statements)

References 32 publications

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“…The calcium content of the solutions used was carefully determined, and the experimental results were corrected for the impurities when necessary. (Meldolesi, 1970) Figure it is clear that the cumulative calcium release is larger after stimulation with secretin, whereas the calcium concentration in the juice is always much higher with caerulein.…”

Section: Introductionmentioning

confidence: 91%

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Secretion of calcium in pancreatic juice.

Ceccarelli¹,

Clémente²,

Meldolesi

1975

The Journal of Physiology

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SUMMARY1. The origin of the calcium secreted by the pancreas has been investigated in vivo in the guinea-pig by a study carried out in parallel (a) in the juice secreted in response to the injection of either secretin or caerulein and (b) in the pancreatic tissue and in cell fractions isolated therefrom.2. In agreement with previous findings we observed that the concentration of calcium is low in the secretin-stimulated and high in the caeruleinstimulated juice. In the latter calcium and protein are proportional (ca. 50 n-mole: mg).3. After i.v. injection of 45Ca the radioactivity decreases rapidly and quasi-exponentially in the blood plasma. A roughly parallel time course is found in the secretin-stimulated juice: the evolution of the juice: plasma radioactivity ratio resembles that observed with the extracellular space marker [3H]D-sorbitol. In contrast, the time course of 45Ca in plasma and caerulein-stimulated juice are not proportional: the high levels characteristic of this juice are reached several minutes after the injection and maintained thereafter. This increase is followed ca. 50 min later by the appearance of the newly synthesized [3H]L-leucine-labelled proteins.4. The pancreatic tissue is rich in calcium which is localized primarily in zymogen granules (ca. 36 n-mole: mg protein) and mitochondria; the soluble cytoplasm is low in calcium.5. The injected "Ca accumulates in zymogen granules faster than [3H]L-leucine-labelled proteins. The 45Ca : protein ratio of these organelles is considerably lower than that of the caerulein-stimulated juice.6. It is concluded (a) that calcium is secreted into the pancreatic juice in two fractions, one (possibly released by simple diffusion) associated with the electrolyte component, the other with the protein of the juice,

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Section: Introductionmentioning

confidence: 91%

“…Onlywhen a separate assay of the protein-incorporated 3H-radioactivity was needed, the samples were precipitated at 4°C with 10 % trichloroacetic acid (TCA) and centrifuged. The precipitates were washed as described previously (Meldolesi, 1970). Aliquots of the TCA-soluble and insoluble samples were dissolved in 10 ml.…”

Section: Introductionmentioning

confidence: 99%

Secretion of calcium in pancreatic juice.

Ceccarelli¹,

Clémente²,

Meldolesi

1975

The Journal of Physiology

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“…in vivo, CCK exerts both a short-term stimulatory effect on pancreatic protein synthesis (Meldolesi, 1970;Morriset & Webster, 1971) and a long-term action on pancreatic enzyme concentration (Maintz, Black & Webster, 1973;Ihse, Arnesto & 431 A. DEMBINSKI AND OTHERS Lanquist, 1976). Exogenous CCK and its natural analogue, caerulein, as employed in this study instead of CCK, are known stimulants of pancreatic growth (Maintz et al 1973;Peterson et al 1978;Dembinski & Johnson, 1980).…”

Section: Discussionmentioning

confidence: 99%

Cholecystokinin receptor antagonism by peptidergic and non‐peptidergic agents in rat pancreas.

Dembiński¹,

Jaworek²,

Konturek³

et al. 1989

The Journal of Physiology

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SUMMARY1. Graded doses of bombesin infused I.v. into conscious rats with chronic pancreatic fistulae induced a dose-dependent stimulation of protein secretion, similar to that obtained with caerulein. This stimulation does not appear to be mediated by cholecystokinin (CCK) receptors because peptidergic (CR-1409) and non-peptidergic (L-364 718) CCK antagonists failed to affect protein secretion at a dose range which caused almost complete suppression of caerulein-induced pancreatic secretion.2. Studies in vitro on isolated rat pancreatic acini revealed that caerulein, pentagastrin and bombesin all showed the same efficacy in their ability to stimulate amylase release. In contrast, CCK antagonists competitively inhibited amylase release induced by caerulein and pentagastrin but not by bombesin or urecholine, indicating that the latter two agents act directly on acinar cells via receptors which are separate from those involved in stimulation induced by caerulein and pentagastrin.3. DNA synthesis, measured by the incorporation of [3H]thymidine into DNA, was significantly stimulated by caerulein, soybean trypsin inhibitor (FOY 305), pentagastrin and by bombesin in a dose-dependent manner. CCK receptor antagonists prevented stimulation of DNA synthesis induced by caerulein, FOY 305 and pentagastrin but not by bombesin.4. This study indicates that bombesin strongly stimulates pancreatic enzyme secretion, with an efficacy similar to that of caerulein, and also exerts a potent growth-promoting action on the pancreas, both effects appearing to be mediated by mechanisms independent of the CCK receptors.

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“…Studies in vivo have shown that glucocorticoids and cholecystokinin (CCK) are involved in the regulation of the biosynthesis of secretory proteins in the rat pancreas [1][2][3][4][5][6]. Glucocortocoids exhibited a selective effect on the pancreatic amylase gene, whereas CCK decreased the biosynthesis of amylase and increased that of serine proteases.…”

Section: Introductionmentioning

confidence: 99%

Regulation of amylase and chymotrypsinogen expression by dexamethasone and caerulein in serum-free-cultured pancreatic acinar AR4-2J cells. Influence of glucose

Estival

Pradel

Wicker‐Planquart

et al. 1991

Biochemical Journal

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The direct effects of dexamethasone and caerulein on two pancreatic enzymes, amylase and chymotrypsin, were determined in AR4-2J cells cultured under serum-free conditions at two glucose concentrations (1.0 and 4.5 g/l). In the absence of any hormone, the higher glucose concentration resulted in a 1.6-1.8-fold increase in the basal levels of amylase and chymotrypsinogen. Dexamethasone (50 nM) increased the biosynthesis and mRNA levels of both enzymes at both glucose concentrations. However, dexamethasone had a more pronounced effect on amylase biosynthesis (5-fold induction) than on chymotrypsinogen biosynthesis (1.8-fold induction). The parallel increases in mRNA and protein indicated the existence of pre-translational regulation. This is in contrast with what was observed in serum-containing media, where a translational regulation of amylase biosynthesis took place, probably under the control of both glucose and some serum factors. By contrast, caerulein (10 nM) exerted a more specific action on chymotrypsinogen. The increases in chymotrypsinogen mRNA were 2.2-and 2.1-fold, and increases in chymotrypsin activity were 1.6-and 2.9-fold at 1.0 and 4.5 g of glucose/litre respectively. Thus the regulation by caerulein occurred mainly through the enhancement of chymotrypsinogen transcription and/or mRNA stabilization.

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

Cited by 32 publications

References 32 publications

Secretion of calcium in pancreatic juice.

Secretion of calcium in pancreatic juice.

Cholecystokinin receptor antagonism by peptidergic and non‐peptidergic agents in rat pancreas.

Regulation of amylase and chymotrypsinogen expression by dexamethasone and caerulein in serum-free-cultured pancreatic acinar AR4-2J cells. Influence of glucose

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