Physiological conditions for the study of basal and meal stimulated exocrine pancreatic secretion in the dog. Absence of feedback inhibition of basal secretion

1982 ◽  
Vol 60 (10) ◽  
pp. 1287-1295 ◽  
Author(s):  
G. Roblès Diaz ◽  
M. A. Devaux ◽  
C. D. Johnson ◽  
Z. Adrich ◽  
H. Sarles
Keyword(s):  
Body Weight ◽  
Pancreatic Juice ◽  
Pancreatic Secretion ◽  
Specific Activity ◽  
Feedback Inhibition ◽  
Secretory Activity ◽  
Experimental Conditions ◽  
Physiological Conditions ◽  
Transient Rise ◽  
Secretion Rates

Pancreatic secretion has been studied in dogs in basal and postprandial conditions, as nearly physiological as possible. When pancreatic juice was excluded from the duodenum pancreatic secretion was not raised. compared with secretion during the return of juice to the duodenum. In fact, in seven mongrels, returning pancreatic juice led a transient rise in pancreatic secretion. This was not seen in five beagles. These results indicate that dogs do not manifest the feedback control of pancreatic secretion by pancreatic juice observed in other species. Pancreatic secretory activity was determined in 10 dogs after stimulation by food. The highest secretion rates occurred during the initial 60 min. The maximal secretion of protein occurred before the maximal secretion of fluid and bicarbonate. The effect of the meal diminished slowly during the subsequent minutes but did not reach basal levels after 2 h. In physiological conditions, maximal pancreatic secretion of fluid and bicarbonate was about one-fifth and of protein was almost one-seventh of the maximal secretory capacity obtained with secretin and cholecystokinin, respectively. Potential specific activity of trypsinogen was unchanged during the different experimental conditions. Trypsinogen output represented a constant average of 20% of protein output. The interindividual variability of pancreatic secretion rates was reduced when outputs were expressed per kilogram of body weight. In general, a significant positive correlation was found between body weight and the secretory outputs. No differences were observed in the response of mongrel and beagle dogs to a meal.

scholarly journals Polyamine and intestinal properties in adult rats

1996 ◽  
Vol 76 (4) ◽  
pp. 627-637 ◽  
Author(s):  
Patricia Deloyer ◽  
Guy Dandrifosse ◽  
Catherine Bartholomeus ◽  
Nadine Romain ◽  
Monique Klimek ◽  
...  
Keyword(s):  
Body Weight ◽  
Specific Activity ◽  
Experimental Conditions ◽  
Adult Rats ◽  
Distal Intestine ◽  
Germ Free ◽  
Polyamine Content ◽  
Intestinal Functions ◽  
Wet Weight ◽  
Specific Activities

We questioned whether polyamines coming from the diet or produced by intestinal microflora or by intracellular metabolism influence intestinal functions. Therefore, we compared pathogen-free rats and germ-free rats receiving a diet with low polyamine content and either treated or not treated with difluoromethylornithine (DFMO) and/or methylglyoxal bis (guanylhydrazone) (MGBG). Wet weight, protein content, DNA content, sucrase (EC3.2.1.48), maltase (EC 3.2.1.20) and lactase (EC 3.2.1.23) specific activities, amounts of putrescine, spennidine and spemine were measured in the mucosa of the proximal and distal intestine. Body weight was also determined. Rats without microflora had a higher specific activity of maltase and higher amounts of spermidine and spermine but lower lactase specific activity than pathogen-free animals; the low-polyamine diet given to gem-free rats had little effect on the functional variables measured (decrease of maltase and lactase specific activities) and did not modify the amounts of polyamines. DFMO and/or MGBG administered to germ-free rats receiving a low-polyamine diet induced modifications of most of the variables studied. Body weight and wet weight of proximal and distal intestine decreased, disaccharidase specific activities decreased, and amounts of polyamines changed according to the inhibitor used. Thus, our results showed that the deprivation of polyamine supply from microflora or from the diet failed, under our experimental conditions, to affect the intestinal properties analysed but exogenous and endogenous polyamine restriction altered general properties of the organism as well as intestinal functions.

Rat pancreatic response to intestinal infusion of intact and hydrolyzed protein

1983 ◽  
Vol 245 (3) ◽  
pp. G394-G398 ◽  
Author(s):  
G. M. Green ◽  
K. Miyasaka
Keyword(s):  
Pancreatic Juice ◽  
Trypsin Inhibitor ◽  
Pancreatic Secretion ◽  
Feedback Inhibition ◽  
Casein Hydrolysate ◽  
Fluid Secretion ◽  
Common Mechanism ◽  
Intraduodenal Infusion ◽  
Intact Proteins ◽  
Hydrolyzed Protein

The effect of partial exclusion of pancreatic juice from the intestine on the pancreatic response to intraduodenal infusion of casein, casein hydrolysate, and trypsin inhibitor was investigated in conscious rats with chronic pancreatic and biliary fistulas. In controls all pancreatic juice collected was returned to the intestine. In partial diversion groups only 10% of the pancreatic juice collected was returned during each collection period. All bile was returned. Partial diversion of pancreatic juice slightly increased the response to NaCl, had no effect on the incremental response to casein hydrolysate, but doubled the incremental protein and volume response to casein infusion. Trypsin inhibitor infusion did not stimulate pancreatic secretion in controls but greatly increased pancreatic protein and fluid secretion in rats with partial diversion of pancreatic juice. The results confirm that protein hydrolysates are weak stimulants of pancreatic secretion in the rat compared with intact proteins and support the view that intact proteins and trypsin inhibitors stimulate pancreatic secretion in the rat by a common mechanism, i.e., by reducing feedback inhibition from luminal pancreatic proteases.

Feedback Inhibition of Adrenocorticotropin Release by Corticosterone Infusions in the Adrenalectomized Rat

1975 ◽  
Vol 53 (3) ◽  
pp. 475-478 ◽  
Author(s):  
William Rotsztejn ◽  
Josée Lalonde ◽  
Maurice Normand ◽  
Claude Fortier
Keyword(s):  
Body Weight ◽  
Infusion Rate ◽  
Feedback Inhibition ◽  
Inhibitory Effect ◽  
Plasma Corticosterone ◽  
Rat Plasma ◽  
Metabolic Clearance ◽  
Experimental Conditions ◽  
Corticosterone Concentration ◽  
Acth Release

Advantage was taken of a specific and sensitive bioassay for rat plasma adrenocorticotropin (ACTH) based on the dispersion of rat adrenal cells with trypsin, to investigate the relationship between plasma corticosterone concentration and inhibition of ACTH release under steady-stale conditions achieved by graded rates (0–5.12 μg/min per 100 g body weight) of intravenous infusion of the steroid for 45 min in 28-day adrenalectomized rats. In contrast to prior reports involving suppression of stress-induced ACTH release, the inhibitory effect of corticosterone was shown, under our experimental conditions, to be exerted also on the basal rate of ACTH secretion. Indeed, a slight though not significant decrease of plasma ACTH concentration was observed with the corticosterone infusion rate of 0.64 μg/min per 100 g body weight, and further progressive and highly significant drops in concentration were recorded for infusion rates of 2.56 and 5.12 μg/min per 100 g body weight. An increase of the metabolic clearance rate of corticosterone, observed as a function of the infusion rate, was ascribed to saturation by the steroid of the plasma transcortin binding sites.

Nonparallel secretion of enzymes by the rabbit pancreas

1986 ◽  
Vol 64 (3) ◽  
pp. 297-302 ◽  
Author(s):  
R. G. Lahaie ◽  
R. Michel ◽  
G. Michel ◽  
J. C. Dagorn
Keyword(s):  
Pancreatic Juice ◽  
Pancreatic Secretion ◽  
Exocrine Pancreas ◽  
Specific Activity ◽  
Experimental Models ◽  
Rabbit Pancreas ◽  
Protein Output ◽  
Recent Claim ◽  
Stimulation Of

Since nonparallel secretion of enzymes by the exocrine pancreas has been demonstrated with several experimental models, we were interested in verifying a recent claim that enzyme secretion remained strictly proportional (parallel) upon stimulation of the in vivo rabbit pancreas. Pancreatic juice was collected by extraduodenal cannulation of the pancreatic duct, in two different protocols. In the first protocol the administration of pentobarbital induces a mild anesthesia. Under this condition, amylase and chymotrypsin secretion remained parallel after cholecystokinin stimulation. In a second protocol, a deeper and constant anesthesia was attained with Fluothane resulting in a lower basal protein output than in the first protocol. Pancreatic secretion was collected under intravenous secretin perfusion (4.5 clinical units∙kg−1∙h−1). After stabilization and basal collection periods, pancreatic secretion was stimulated with an i.v. bolus injection of either cholecystokinin (2 Ivy dog units/kg), caerulein (0.1 μg/kg), or carbachol (6 μg/kg). Upon stimulation of the pancreas, protein output increased an average of 30-fold and there was a concomitant 20–25% decrease in the ratio of the specific activities of amylase to chymotrypsin which resulted from a greater increase in the specific activity of chymotrypsin in pancreatic juice after stimulation of secretion. Thus, under appropriate conditions, nonparallel secretion of enzymes by the exocrine pancreas can be demonstrated in yet another experimental model. Furthermore, the proportion of amylase and chymotrypsin activities in pancreatic juice are once more shown to be dependent, up to a threshold, upon the rate of protein output by this exocrine gland.

Effects of age, body size and growth hormone on level of tryptophan peroxidase-oxidase in rat liver

1959 ◽  
Vol 197 (1) ◽  
pp. 65-67 ◽  
Author(s):  
Richard S. Rivlin ◽  
W. Eugene Knox
Keyword(s):  
Growth Hormone ◽  
Body Weight ◽  
Enzyme Activity ◽  
Body Size ◽  
Rat Liver ◽  
Specific Activity ◽  
Bovine Growth Hormone ◽  
Physiological Conditions ◽  
Enzyme Adaptation

The specific activity of rat liver tryptophan peroxidase increased with age, and at 400 days was more than double the level at 38 days of age. The amount of enzyme per 100 gm body weight also increased significantly. This change of enzyme activity with age was attributed to a substrate-induced enzyme adaptation occurring under physiological conditions caused by the tryptophan available for catabolism as growth slowed. Bovine growth hormone injections increased the level of the enzyme in rats.

In vivo Production of Soluble Inorganic Pyrophosphatases in Two Strains of Vibrio cholerae

1970 ◽  
Vol 24 (1) ◽  
pp. 38-41
Author(s):  
Taslima Taher Lina ◽  
Mohammad Ilias
Keyword(s):  
Vibrio Cholerae ◽  
Specific Activity ◽  
Experimental Conditions ◽  
Environmental Strain ◽  
Cell Extracts ◽  
Atcc Strain ◽  
The Family ◽  
Effects Of Ph ◽  
Vibrio Cholerae O1

The in vivo production of soluble inorganic pyrophosphatases (PPases) was investigated in two strains, namely, Vibrio cholerae EM 004 (environmental strain) and Vibrio cholerae O1 757 (ATCC strain). V. cholerae is known to contain both family I and family II PPase coding sequences. The production of family I and family II PPases were determined by measuring the enzyme activity in cell extracts. The effects of pH, temperature, salinity of the growth medium on the production of soluble PPases were studied. In case of family I PPase, V. cholerae EM 004 gave the highest specific activity at pH 9.0, with 2% NaCl + 0.011% NaF and at 37°C. The strain V. cholerae O1 757 gave the highest specific activity at pH 9.0, with media containing 0% NaCl and at 37°C. On the other hand, under all the conditions family II PPase did not give any significant specific activity, suggesting that the family II PPase was not produced in vivo in either strains of V. cholerae under different experimental conditions. Keywords: Vibrio cholerae, Pyrophosphatases (PPases), Specific activityDOI: http://dx.doi.org/10.3329/bjm.v24i1.1235 Bangladesh J Microbiol, Volume 24, Number 1, June 2007, pp 38-41

The effects of furosemide and bumetanide on lung liquid production by in vitro lungs from fetal guinea pigs

1990 ◽  
Vol 68 (8) ◽  
pp. 1131-1135 ◽  
Author(s):  
J. Thom ◽  
A. M. Perks
Keyword(s):  
Body Weight ◽  
Guinea Pig ◽  
Guinea Pigs ◽  
Loop Diuretics ◽  
Dilution Technique ◽  
Blue Dextran ◽  
Lung Fluid ◽  
Lung Liquid ◽  
Secretion Rates

Lungs from fetal guinea pigs of 61 ± 3 days of gestation were supported in vitro for 3 h, and lung liquid secretion rates were measured by a dye dilution technique based on Blue Dextran 2000. Ten preparations that had received no treatment showed an average secretion rate of 1.12 ± 0.28 mL∙kg−1 body weight∙h−1 during the first hour, and there were no significant changes over the following 2 h. In studies of 54 fetal lungs, furosemide, bumetanide, control ethanol carrier, or saline alone were placed in the supporting medium during the middle hour of the 3-h incubations (ABA design). Furosemide at 10−3 M reduced secretion 83.4 ± 16.8%; at 10−4 and 10−5 M it produced smaller reductions. Bumetanide at 10−3 M usually produced reabsorption (129.9 ± 23.0% reduction), at 10−4 M it reduced secretion 30.9 ± 11.8%, but at 10−5 M it was ineffective. Control carrier and saline were without effect. The ability of the loop diuretics to produce reabsorption of fluid in some preparations suggests the unmasking of an active reabsorptive process. The results also suggest that lung liquid secretion in the fetal guinea pig, as in the sheep, is dependent on a Na+ and Cl− cotransport system.Key words: fetus, lung fluid, bumetanide, furosemide.

Estimation of water content by tritium dilution of animals subjected to rapid live-weight changes

1969 ◽  
Vol 72 (1) ◽  
pp. 31-40 ◽  
Author(s):  
W. R. McManus ◽  
R. K. Prichard ◽  
Carolyn Baker ◽  
M. V. Petruchenia
Keyword(s):  
Body Weight ◽  
Water Content ◽  
Total Body Water ◽  
Compensatory Growth ◽  
Specific Activity ◽  
Tritiated Water ◽  
Body Water ◽  
Under Nutrition ◽  
The Mean ◽  
Total Body

SUMMARYThe use of tritiated water to estimate total body-water content of animals experiencing recovery from under-nutrition was studied.The time for equilibration of tritiated water (TOH), given intraperitoneally, with total body water (TBW) was determined in rabbits and in rats. As judged by the specific activity of blood water, equilibration had occurred by 76–125 min in the rabbit and did not appear to be affected by the plane of nutrition. However, between slaughter groups the specific activity of water obtained from the liver 180 min after injection of TOH was significantly different from the specific activity of water simultaneously obtained from the blood plasma. It is concluded that the liver is not a suitable tissue to use for testing achievement of equilibration.As judged by the specific activity of blood water compared to that of water from the whole body macerate, equilibration in mature rats either in stable body condition or undergoing rapid compensatory growth occurred in less than 60 min.A trial comparing TOH-space (corrected by 3% body weight) and actual TBW (by desiccation) was conducted on thirty rabbits which experienced under-nutrition followed by compensatory growth.Prior to under-nutrition the agreement between actual and estimated TBW was satisfactory and within 2·3%. During compensatory growth the agreement was poor— the TOH values over-estimating actual TBW by about 12%.A trial with mature rats confirmed the findings with rabbits. For rats in stable body weight the mean estimated TOH-space for fourteen animals was within 1·2% of the actual TBW. For fourteen rats undergoing compensatory growth the mean estimated TOH-space (corrected by 3% body weight) overestimated actual TBW by 6·2%.

Microinjection of exogenous somatostatin in the dorsal vagal complex inhibits pancreatic secretion via somatostatin receptor-2 in rats

2007 ◽  
Vol 292 (3) ◽  
pp. G746-G752 ◽  
Author(s):  
Zhuan Liao ◽  
Zhao-Shen Li ◽  
Yan Lu ◽  
Wei-Zhong Wang
Keyword(s):  
Pancreatic Secretion ◽  
Exocrine Pancreas ◽  
Feedback Inhibition ◽  
Somatostatin Receptor ◽  
Inhibitory Effect ◽  
Receptor Subtype ◽  
Dependent Manner ◽  
Dorsal Vagal Complex ◽  
Somatostatin Receptor Antagonist ◽  
Dose Dependent

Previous studies have suggested that somatostatin inhibits pancreatic secretion at a central vagal site, and the dorsal vagal complex (DVC) is involved in central feedback inhibition of the exocrine pancreas. The aim of this study was to investigate the effect of exogenous somatostatin in the DVC on pancreatic secretion and the somatostatin receptor subtype(s) responsible for the effect. The effects of somatostatin microinjected into the DVC on pancreatic secretion stimulated by cholecystokinin octapeptide (CCK-8) or 2-deoxy-d-glucose (2-DG) were examined in anesthetized rats. To investigate the somatostatin inhibitory action site, a somatostatin receptor antagonist [SRA; cyclo(7-aminoheptanoyl-Phe-d-Trp-Lys-Thr)] was microinjected into the DVC before intravenous infusion of somatostatin and CCK-8/2-DG. The effects of injection of a somatostatin receptor-2 agonist (seglitide) and combined injection of somatostatin and a somatostatin receptor-2 antagonist (CYN 154806) in the DVC on the pancreatic secretion were also investigated. Somatostatin injected into the DVC significantly inhibited pancreatic secretion evoked by CCK-8 or 2-DG in a dose-dependent manner. SRA injected into the DVC completely reversed the inhibitory effect of intravenous administration of somatostatin. Seglitide injected into the DVC also inhibited CCK-8/2-DG-induced pancreatic protein secretion. However, combined injection of somatostatin and CYN 154806 did not affect the CCK-8/2-DG-induced pancreatic secretion. Somatostatin in the DVC inhibits pancreatic secretion via somatostatin receptor-2, and the DVC is the action site of somatostatin for its inhibitory effect.

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