Non‐parallel enzyme secretion from rat pancreas: in vivo studies.

Dagorn, Jean–Charles

doi:10.1113/jphysiol.1978.sp012393

Cited by 51 publications

(32 citation statements)

References 26 publications

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“…This is associated with a modulatory effect of CCK on biosynthesis, acting preferentially on serine proteases (Renaud et al 1986, Pradel et al 1993, Lloste et al 1994, de Dios et al 1997b. In agreement with previous reports (Dagorn 1978, Grendell et al 1984, our results also show a non-parallel secretion of enzymes in response to short-term CCK stimulation. Under these conditions, differential release of a previously synthesized product may be taking place.…”

Section: Discussionsupporting

confidence: 82%

“…Among other effects, CCK regulates the exocrine pancreatic function, and its major action on acinar cells is to stimulate digestive enzyme secretion (Williams & Yule 1993). Under some conditions (Dagorn 1978, Grendell et al 1984, de Dios et al 1997b, the proportion of different enzymes is 'non-parallel'. A selective exocytosis of zymogen granules with different enzyme content has been suggested (Adelson & Miller 1989), however, the mechanism for this phenomenon is still not completely understood.…”

Section: Introductionmentioning

confidence: 99%

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Selective exocytosis of zymogen granules induces non-parallel secretion in short-term cholecystokinin-stimulated rats

Dios¹,

Garcia-Montero²,

Órfão³

et al. 1999

Journal of Endocrinology

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Parallel studies on pancreatic enzyme secretion and zymogen granule enzyme composition have been carried out in rats subjected to infusion of cholecystokinin (CCK) (1·25 µg/kg per h) over 30 min. Flow cytometric analysis showed a significant decrease in the mean value of granule size after CCK stimulation. The amount of trypsinogen stored in each individual zymogen granule was significantly lower at 30 min of CCK infusion, but no variation in intragranular amylase content was observed. As a result, the amylase/trypsinogen ratio was significantly increased in the zymogen granules that remained in the pancreas of rats stimulated with CCK for 30 min. A significantly greater proportion of trypsin than amylase was secreted after 30 min CCK infusion. Our results support the existence of different types of granules loaded with different proportions of enzymes. We conclude that short-term CCK stimulation induces the selective release of large granules containing a high proportion of trypsinogen, which leads to a non-parallelism of enzyme secretion.

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Section: Discussionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Selective exocytosis of zymogen granules induces non-parallel secretion in short-term cholecystokinin-stimulated rats

Dios¹,

Garcia-Montero²,

Órfão³

et al. 1999

Journal of Endocrinology

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“…Control experiments have shown that albumin did not impair the specific activity of chymotrypsinogen after completion of the activation. (Dagorn, 1978 same time. However, the intensity of the stimulation was not the same for the three enzymes.…”

Section: Enzymatic Assaysmentioning

confidence: 71%

“…It was concluded that the non-parallelism between enzyme secretions can occur in the rat upon pancreozyminic or cholinergic stimulation in vitro as well as in vivo (Dagorn, 1978) provided basal protein output is low enough. This is not the case when the tissular integrity of the pancreas is lost, such as in experiments on lobules.…”

Section: Discussionmentioning

confidence: 99%

Non‐parallel enzyme secretion from rat pancreas in vitro studies.

Dagorn¹,

Estival²

1979

The Journal of Physiology

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SUMMARY1. The relative variations of rat pancreatic amylase versus lipase and chymotrypsinogen secretions have been studied in vitro with the help of two different techniques: in situ organ perfusion and incubation of pancreatic lobules.2. In experiments on the perfused pancreas, with 8 C u. kg-1 hr-1 secretin added to the perfusion fluid, cholecystokinin-pancreozymin (8 ID u. kg-1) or pilocarpine (15 mg kg-1) both resulted in a significant change in the enzyme proportions in the juice.3. In experiments on pancreatic lobules, the addition to the incubation medium of secretin (10-7 M), alone or associated with cholecystokinin-pancreozymin (8 x 10-7 M) or pilocarpine (IOOM) did not induce any change in the enzyme proportions in secretion.4. It was concluded that the non-parallelism between enzyme secretions can occur in the rat upon pancreozyminic or cholinergic stimulation in vitro as well as in vivo (Dagorn, 1978) provided basal protein output is low enough. This is not the case when the tissular integrity of the pancreas is lost, such as in experiments on lobules.5. This work confirms that pancreatic secretion derives from two intrapancreatic pools of different enzymatic composition, and gives a possible explanation for some discrepancies from the literature on the existence of non-parallel secretion.

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“…The converse is true for a protein-rich diet (Ben Abdeljilil and Desnuelle, 1964) and the same phenomenon has been described for the lipase-colipase system (Bazin et al, 1978). Such modifications of pancreatic content are now thought to be induced by changes in the biosynthetic rate of individual enzymes rather than by non-parallel secretion (Palade, 1975;Dagorn, 1978) or differential enzyme catabolism (Kramer and Poort, 1972). Changes in the individual rates of enzyme biosynthesis have been shown to occur in the developing embryonic pancreas (Kemp et al, 1972) and also after 30 days (Reboud et al, 1966) and more recently after 5 days of dietary adaptation in the adult rat (Poort and Poort, 1980).…”

Section: Enzymes and Hormones Synthesismentioning

confidence: 99%