Hormonal Control of Pancreatic Growth

Mainz, David L.; Black, Owen; Webster, Peter

doi:10.1172/jci107418

Cited by 239 publications

(84 citation statements)

References 20 publications

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“…Pancreases were immediately excised, dissected to remove the fat, weighed, and split in three parts for determination of different parameters. DNA was extracted and determined from =lo0 mg of tissue (one-tenth of the gland) homogenized in 0.6-N perchloric acid (12,13). The rest of the gland was divided into two identical pieces.…”

Section: Methodsmentioning

confidence: 99%

Alterations of Pancreatic Growth and of GP-2 Content in the Reserpinized Rat Model of Cystic Fibrosis

1989

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ABSTRACT. The chronically reserpinized rat is an experimental model for cystic fibrosis. In this study, we report the effects of two doses of reserpine (0.5 and 1.0 m g kg-'. d-') on the growth of the pancreas and on its content of the glycoprotein GP-2, a characteristic protein of the zymogen granule. An assessment of the effects of secondary malnutrition induced by the drug was also performed by adding a group of pair-fed animals. During the 7 d of treatment, body wt and food intake were monitored. These two parameters were significantly affected from the 4th d on. Pancreatic wt, DNA, protein, and activity of amylase and chymotrypsinogen were measured after 4 and 7 d of treatment; lipase activity and GP-2 content, after 7 d. Although the DNA content never did change, total protein diminished by 27% at the higher dose of reserpine. Pancreatic wt, amylase activity and GP-2 content were reduced by the treatment, while chymotrypsinogen and lipase activities were increased. Effects on pancreatic wt, amylase, chymotrypsinogen, and GP-2 were dose-dependent. Malnutrition had effects similar to reserpine on body wt, protein, amylase, and chymotrypsinogen. Pancreatic wt, lipase, and GP-2, however, were specifically altered by the chronic reserpine treatment. It is concluded from these results that reserpine induces, in the pancreas, specific alterations that are distinguishable from the accompanying malnutrition. These findings support the use of pancreatic wt, lipase, and GP-2 as specific markers of the effects of the drug on the pancreatic tissue in the chronically reserpinized rat model for cystic fibrosis. This is the first report of a modulation of GP-2 content induced by any treatment. It suggests that GP-2 is directly affected in the pancreas of the chronically reserpinized rat. (Pediafr Res 25: [478][479][480][481]1989) Abbreviations CF, cystic fibrosis GP-2, the major pancreatic granule membrane glycoprotein R group, rats injected at 0.5 mg . kg-'. d-' with reserpine 2R group, rats injected at 1.0 mg . kg-'. d-' with reserpine CF is the most common genetic disease in the Caucasian population, occurring once in every 2000 live births. It is characterized by a generalized disorder of the exocrine glands. The

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Section: Methodsmentioning

confidence: 99%

Alterations of Pancreatic Growth and of GP-2 Content in the Reserpinized Rat Model of Cystic Fibrosis

1989

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“…DNA in the pancreatic tissue was assayed as follows : DNA from the homogenated pancreas was extracted into 0.5 N perchloric acid according to the method of MAINZ et al (1973), and then assayed colorimetrically by the method of VOLKIN and CoHN (1954).…”

Section: Methodsmentioning

confidence: 99%

Secretory responses of hypertrophied rat pancreas induced by repeated oral administrations of a synthetic protease inhibitor.

Yonezawa

1983

Jpn.J.Physiol

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A dose of -(4-guanidinobenzoyloxy)phenylacetate methanesulfonate; 100 mg/kg body weight] was administered orally once a day for 30 days to a group of rats (FOY group). To the control group of rats, 10 ml/kg body weight of distilled water (a solvent of FOY-305) was administered in the same way. The FOY-305 administration induced hypertrophy of the pancreas : the increase in wet weight of the pancreas was significantly higher than the increase in DNA content. The administration also induced hyperpyknia in the FOY group as shown by the increased concentration of constituents (amylase, trypsinogen, and chymotrypsinogen) in the pancreas.The secretory responses of the exocrine pancreas to stimulation with cholecystokinin (CCK) were examined in vivo. The secretory responses induced by lowered doses of CCK in the FOY group were slightly greater than those in the control group, but the differences were not statistically significant. On the other hand, the responses induced by higher doses of CCK were significantly greater than those in the control group. The secretory responses to stimulation with CCK or acetylcholine (ACh) were examined further in vitro using an isolated perfused pancreas. Protein output induced by lower doses of the secretagogues (146-730 pM CCK or 10 nM ACh) was similar in the control and the FOY groups, but the output induced by higher doses of the secretagogues (1,460 pM CCK or 30-100 nM ACh) in the FOY group was significantly larger than that in the control group.The present results provided evidence that the FOY-305-induced hypertrophy and hyperpyknia of the rat pancreas coincided with potentiation of secretory responses to higher doses of the secretagogues.

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“…Pancreatic synthesis and secretion is predominantly influenced by gastrointestinal hormones; CCK plays a major role by direct action on pancreatic acini (Rothman & Wells, 1967;Mainz et al 1973;Liddle et al 1985). The presence of tannins in the diet, through their effect on enzymes in the gut, may augment the secretion of CCK.…”

Section: Meanmentioning

confidence: 99%

Activities of enzymes of the pancreas, and the lumen and mucosa of the small intestine in growing broiler cockerels fed on tannin-containing diets

1991

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Diets containing vegetable tannins, predominantly hydrolysable gallotannins, at levels of 13.5, 25 and 50 g/kg were fed to growing broiler cockerels to examine their effect on enzymes in the pancreas, the intestinal lumen and the intestinal mucosa. Pancreas weight per unit live weight showed a significant (P < 0.05) increase with increasing level of dietary tannin while that of the liver remained unaffected. Trypsin (EC 3 . 4 . 2 1 .4) and a-amylase (EC 3.2.1.1) activities in the pancreas of birds fed at the highest level of tannins were more than double those from birds fed on a tannin-free control diet. In the intestinal lumen inhibition of trypsin activity increased with increasing level of dietary tannin; a-amylase activity was inhibited at intermediate tannin levels but was restored at the highest level. Dipeptidase (EC 3.4.13.11) and sucrose a-glucosidase (disaccharidase) (EC 3.2.1.48) in the intestinal mucosa were both inhibited by tannins. Growth of the birds and digestibility of nitrogen were adversely affected by the tannin-containing diets.Tannin : Pancreatic enzymes : Brush border enzymes : Cockerel It is well established that tannins are potential protein precipitants (Hagerman & Butler, 1980;Hagerman & Klucher, 1986; Makker et al. 1987) and that they reduce the digestibilities of proteins (Mohammed & Ahnied, 1987) when present in animal feeds. Elevated faecal nitrogen excretion associated with ingestion of tannin-containing feeds is ascribed largely to interactions between either tannins and dietary protein or tannins and digestive enzymes, or both. However, Mitjavilla et al. (1977) concluded that the excess faecal N is mostly a result of mucus hypersecretion.Studies in vitro (Griffiths, 1981 ;Lumen & Salamat, 1980;Horigome et al. 1988) and in vivo (Griffiths & Moseley, 1980; Horigome er al. 1988) have demonstrated the formation of tannin-enzyme complexes. However, adopting a technique in vitro more relevant to the situation in vivo, Mole & Waterman (1987) showed that trypsin retained all its activity in the presence of tannic acid when the system included a substrate protein (bovine serum albumin ; BSA) and glycocholic acid, indicating that under such conditions tannins have a preferential affinity for dietary protein over enzyme protein. In previous work Mole & Waterman (1985) had shown that the formation of complexes between tannins and BSA, used as a substrate for proteolysis, could result in either enhancement or inhibition of proteolysis, or no effect at all depending on the tannin:BSA ratio in the complex.In contrast to what had been reported with rats (Griffiths & Moseley, 1980; Horigome et ul. 1988), tannins were shown to exert no effect on protein digestion by insect herbivores (Martin et ul. 1985(Martin et ul. , 1987 in terms of changes in activities of enzymes in the lumen of the small intestine, in order to provide further insight into the mode of action of dietary tannins. A further aim was to examine the effect of dietary tannins on the activity of membrane-bound enzymes wh...

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Hormonal Control of Pancreatic Growth

Cited by 239 publications

References 20 publications

Alterations of Pancreatic Growth and of GP-2 Content in the Reserpinized Rat Model of Cystic Fibrosis

Alterations of Pancreatic Growth and of GP-2 Content in the Reserpinized Rat Model of Cystic Fibrosis

Secretory responses of hypertrophied rat pancreas induced by repeated oral administrations of a synthetic protease inhibitor.

Activities of enzymes of the pancreas, and the lumen and mucosa of the small intestine in growing broiler cockerels fed on tannin-containing diets

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