Parallel secretion of digestive enzymes by the in vitro rabbit pancreas

Ml, Steer; Glazer, G

doi:10.1152/ajplegacy.1976.231.6.1860

Cited by 36 publications

(8 citation statements)

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“…2, A and B), thus indicating the occurrence of parallel secretion of PLA 2 and colipase, a known marker of pancreatic lipolysis. The cosecretion of PLA 2 with other pancreatic enzymes or coenzymes could have been predicted from other studies demonstrating parallel pancreatic cosecretion of lipase and colipase (3) and also of nonlipolytic enzymes, proteases, and amylase (21,22). This observation is also consistent with the role of phospholipases in intraluminal phospholipid and triglyceride digestion and the subsequent role of phospholipids in enterocyte lipid transport.…”

Section: Discussionsupporting

confidence: 84%

Parallel Secretion of Pancreatic Phospholipase A2, Phospholipase A1, Lipase, and Colipase in Children with Exocrine Pancreatic Dysfunction

Nouri-Sorkhabi¹,

Chapman

Kuchel

et al. 2000

Pediatr Res

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The cosecretion of pancreatic lipase and colipase are important in normal fat digestion. As adsorption of phosphatidylcholine to the lipid substrate interferes with lipase activity, hydrolysis to lysophosphatidylcholine with subsequent desorption is also essential for fat digestion. There are some data regarding the secretion of pancreatic phospholipases in normal adults but none in children or patients with pancreatic disease. In the present study, we aimed a) to develop an accurate fast assay method to measure phospholipase A 2 and b) to determine the secretion rate of pancreatic phospholipase A 2 and whether it is cosecreted with lipase and colipase in children with exocrine pancreatic dysfunction. Nine male patients aged 0.5 to 16 y (seven with cystic fibrosis, two with malabsorption) underwent pancreatic stimulation tests. Their colipase and lipase secretion rates were measured by titrimetric methods and phospholipase A 2 and A 1 by phosphorus magnetic resonance spectroscopy ( 31 P NMR). It was found that the phospholipases, colipase, and lipase were absent in the two patients with pancreatic insufficiency. In patients with normal absorption, there were marked inter-and intrasubject variations of lipase, colipase, and phospholipase secretion rates that were consistent with the degree of exocrine pancreatic dysfunction. However, in the three 20-min stimulation periods of the pancreatic function test, pancreatic phospholipase is cosecreted with lipase and colipase, and average colipase and phospholipase A 2 secretion rates follow a similar or parallel pattern. These findings are consistent with the important role of pancreatic phospholipases in intestinal phospholipid hydrolysis leading to the desorption of phospholipids from the lipid substrate and enhancing lipid hydrolysis and phospholipid absorption. Abbreviations CEH, carboxyl ester hydrolase CF, cystic fibrosis GPC, glycerophosphocholine lysoPC, lysophosphatidylcholine MCC, mucocutaneous candidiasis and polyendocrinopathy NMR, nuclear magnetic resonance PC, phosphatidylcholine PLA 1 , phospholipase A 1 PLA 2 , phospholipase A 2 PI, pancreatic insufficient PS, pancreatic sufficient Exocrine pancreatic function has been well characterized in children with pancreatic disease with the use of quantitative pancreatic function tests (1-3). To determine the relationship between residual pancreatic function and fat absorption, sensitive titrimetric assays were developed for lipase and the lipase cofactor colipase (4) and their secretion rates compared with fecal fat excretions in children with CF, Shwachman syndrome, or controls (3,5). These studies demonstrated that patients with normal fat absorption had a wide range of enzyme/coenzyme secretion from less than 5% up to within the normal control range; and the threshold for lipolytic failure was near 1% of average control colipase values, i.e. patients with values below this level had fat malabsorption and above this level normal absorption. These observations led to the currently accepted definition that patie...

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Section: Discussionsupporting

confidence: 84%

Parallel Secretion of Pancreatic Phospholipase A2, Phospholipase A1, Lipase, and Colipase in Children with Exocrine Pancreatic Dysfunction

Nouri-Sorkhabi¹,

Chapman

Kuchel

et al. 2000

Pediatr Res

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“…It is remarkable that independent groups did not observe the same effect al though they apparently used the same exper imental protocols [6,8,12,19,22,[24][25][26][27], Slight but nevertheless important differences in experimental procedures, however, may not have been taken into consideration. One important point might be the duration of fasting, which is known to have an influence on pancreatic enzyme secretion [9,11,13], or the influences of slow spontaneous changes in pancreatic protein composition, which can not be controlled in acute experiments.…”

Section: Introductionmentioning

confidence: 99%

Rapid Adaptation of Pancreatic Enzyme Secretion in the Conscious Rat

Keim¹

1986

Ann Nutr Metab

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The influence of fasting and dietary modulation on basal and stimulated pancreatic enzyme secretion was studied in conscious rats with cannulated pancreatic ducts. Two days’ fasting decreased pancreatic secretion by about 30%. After stimulation of the secretion rate by acute derivation of pancreatic juice or by intravenous infusion of cerulein (0.2 µg/kg/h) no rapid change of enzyme composition was found. In further experiments, two groups of rats were fed with carbohydrate-rich and carbohydrate-poor diets, respectively. After pancreatic duct cannulation and a postsurgical recovery period, the diets were interchanged. An adaptation of pancreatic enzyme secretion to the new diet was observed in pancreatic juice. Stimulation of the secretion rate during the adaptation process by acute derivation of the juice or by intravenous infusion of either cerulein, secretin, carbachol or cerulein plus secretin did not further modify the composition of pancreatic proteins. ‘Nonparallel secretion of enzymes was never found when sufficient time for recovery from pancreatic duct surgery was allowed.

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“…Furthermore, it was postulated that this change in composition of secreted en zymes is specific to the diet fed, e.g. that dur ing digestion of a carbohydrate meal, the secretion of amylase is much more pro nounced than that of other enzymes [7,32], An increasing number of studies attempt to confirm or to disprove these findings using in vitro rabbit pancreas [1,26,27,30,31], guinea pig pancreatic lobules [22], anesthe tized or conscious rats [4-7, 9, 11, 17, 32], Even when independent groups used appar ently the same experimental protocol, differ ent results were obtained [9,11,17,26,27,30,31]. Remarkably few experiments have been done in conscious rats [4,5] compared to the numerous in vitro techniques.…”

Section: Discussionmentioning

confidence: 99%

“…This does not exclude that the phenomenon of 'non parallelism' may exist under less physiologi cal conditions or under conditions yet un known. It remains unclear, why some inves tigators constantly find this nonparallelism [26,27], whereas others do not [30,31],…”

Section: Discussionmentioning

confidence: 99%

Rapid Adaptation of Pancreatic Enzyme Secretion in the Conscious Rat

Keim¹

1986

Ann Nutr Metab

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Pancreatic protein composition in basal and stimulated pancreatic juice was studied in conscious rats with cannulated pancreatic ducts. The animals were fed with 3 different diets for 14 days. Secretion rate was stimulated by acute derivation of the juice, intravenous infusion of cerulein and intraduodenal infusions of either amino acids, fat or carbohydrate. In the juice the amount of secretory proteins was measured. The various secretory stimuli did not lead to any rapid change of composition of the secreted enzymes. A so-called ‘nonparallel secretion’ of pancreatic enzymes could not be found in the conscious rat.

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Parallel secretion of digestive enzymes by the in vitro rabbit pancreas

Cited by 36 publications

References 0 publications

Parallel Secretion of Pancreatic Phospholipase A2, Phospholipase A1, Lipase, and Colipase in Children with Exocrine Pancreatic Dysfunction

Parallel Secretion of Pancreatic Phospholipase A2, Phospholipase A1, Lipase, and Colipase in Children with Exocrine Pancreatic Dysfunction

Rapid Adaptation of Pancreatic Enzyme Secretion in the Conscious Rat

Rapid Adaptation of Pancreatic Enzyme Secretion in the Conscious Rat

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