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Stimulatory Effect Ofpancreozymin-Cholecystokinin on Calcium Secretion in Pancreatic Juice of Dogs 479

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Stimulatory Effect Ofpancreozymin-Cholecystokinin on Calcium Secretion in Pancreatic Juice of Dogs 479 Gut: first published as 10.1136/gut.13.6.477 on 1 June 1972. Downloaded from Gut, 1972, 13, 477-482 Stimulatory effect of pancreozymin-cholecystokinin on calcium secretion in pancreatic juice of dogs2'3 H. GOEBELL1, Ch. STEFFEN, AND Ch. BODE From the Department of Medicine, Philipps-Universitdt, Marburg/Lahn, Germany SUMMARY In four dogs with a permanent duodenal Thomas fistula the secretion ofcalcium, sodium, potassium, protein, and two pancreatic enzymes in pancreatic juice was studied. Infusion of secretin led to a decrease in concentration of calcium and of protein with increasing rates of fluid production. Pancreozymin-cholecystokininwas given in single injections superimposed on the secretin-stimulated flow of juice. This hormone stimulated the secretion of both calcium and enzyme protein in a parallel and closely correlated fashion. The secretion of this protein-bound calcium fraction I is assumed to occur in the acinar cell. A calcium fraction II, which was independent of protein secretion and pancreozymin stimulation, was demonstrated in concentrations of about 0.4 to 0.6 m-equiv/l. This fraction is thought to originate in the interstitial fluid. The secretion of two calcium-containing fluids is in accordance with the two-component theory of secretion proposed by Hollander and Birnbaum (1952). The concentration of sodium and potassium in pancreatic juice of dogs, using a permanent duodenal pancreatic juice has been found to lie in the same Thomas cannula. range as that in the serum under different rates of http://gut.bmj.com/ flow (Johnston and Ball, 1930; Solomon, 1952; Methods Dreiling and Janowitz, 1956); In contrast, it has been known since the investigations of Ball (1930) Four male mongrel dogs with a mean weight of 25 kg that the concentration of calcium in pancreatic were equipped under pentobarbital anaesthesia with juice, at 1-2 m-equiv/l, is much lower than in the a permanent duodenal cannula according to the serum. This suggests that the entrance of calcium procedure described by Thomas (1959). The access- into the pancreatic juice is governed by a mechanism ory ducts were ligated. The animals were allowed on September 27, 2021 by guest. Protected copyright. which is different from that responsible for sodium to recover for four weeks after operation. The and potassium movements. experiments were then carried out once or twice a In human subjects with normal pancreatic week. Before beginning the experiments the animals function we found a significant increase in calcium were trained to stand in a harness. Food was concentration and output in duodenal juice following withdrawn for 12 hours before each experiment. The the administration of pancreozymin-cholecystokinin investigations were made on the conscious animals (Goebell, Bode, and Horn, 1970a). This suggested a (first part of standard experiment), as well as under stimulatory action of this gastrointestinal hormone light anaesthesia with pentobarbital (Nembutal on the secretion of calcium in the pancreas. To 25 mg/kg). The pancreatic juice was collected confirm this hypothesis we studied the influence of continuously in five or 10-minute periods in ice- secretin and pancreozymin-cholecystokinin on the cooled, 10-ml graduated tubes. The volume of secretion of calcium and enzyme protein in the pure pancreatic flow was stimulated throughout the course of the experiments by a constant infusion of 'Present address: Dr H. Goebell, D-79 Ulm/Donau, Zentrumfur 1 clinical unit ofsecretinl/kg per hour viathe femoral Tumere Medi£in, Section of Gastroenterology, University of Ulm, Steinhovelstr. 9. vein, the corresponding amount of secretin per hour 'Some of the results given in this paper were presented at the 4th being dissolved in 30 ml of 0.9 % NaCl. The secreted World Congress of Gastroenterology, Copenhagen, 1970. pancreatic juice was constantly replaced during the 'Supported by grant GO 11816 from the Deutsche Forschungsge- experiments by the infusion of an equal volume of meinschaft. 0.9 % saline solution into a femoral vein. In the Received for publication 29 February 1972. 'Secretin, Karolinska Institut (Professor Jorpes), Stockholm. 477 Gut: first published as 10.1136/gut.13.6.477 on 1 June 1972. Downloaded from 478 H. Goebell, Ch. Steffen, and Ch. Bode presence of a secretin-stimulated flow of juice, Results pancreozymin-cholecystokinin (CCK1) was injected intravenously (2.5 clinical units per kg body weight). BASAL SECRETION In some experiments increasing doses of secretin The volume ofjuice produced under basal conditions per kg per hour were infused by means of a motor varied from 0.2 to 05 ml per 10 minutes. The pump (Perfusor, Braun, Melsungen, Germany). concentration of calcium and protein was high, ie, Sodium, potassium, and calcium were assayed in about 5-6 m-equiv of calcium/l and 30 mg-40 mg of triplicate in the pancreatic juice by flame photometry protein/ml. (flame photometer Eppendorf, Hamburg). Protein was measured without precipitation, using the RESPONSE TO SECRETIN INFUSION biuret method according to Weichselbaum as The start of continuous infusion of secretin with 1 modified by Beisenherz, Boltze, Buicher, Czok, clinical unit/kg/hr promptly caused the volume to Garbade, Meyer-Arendt, and Pfleiderer (1953). increase to about 1 ml/minute, as shown in the Turbidity was eliminated by the addition of KCN to standard experiment in Figure 1. The concentration the test tube (Bode, Goebell, and Staehler, 1968). of bicarbonate rose to about 120 to 140 m-equiv/l. Bicarbonate was measured by titration with 0-01 M Concomitantly, the concentrations of calcium and NaOH after the addition of 0.01 M HCI and boiling protein fell, together with the enzyme activities (Hodes, 1953); the activity of trypsin was measured (Fig. 2 and Table I). The concentration of calcium spectrophotometrically with N-benzoylarginine- was found to lie between 0.6 and 0.8 m-equiv/l. The ethylester (BAEE) (Schwert and Takenaka, 1955). concentration of protein decreased to a mean value For activation 1 ml of the juice was incubated with 1 ml of 0.05 M tris-5 % CaCl2-buffer, pH 7.8, con- Secretin Five Minutes Thirty Minutes taining 0.05 mg enterokinase in 1 ml for one hour at Infusion after Pancreo- after Pancreo- 25°C. Lipase was estimated with the pH-stat (l U/kg hr) zymin zymin titration method of Marchis-Mouren, Sarda, and (n = 20) (n = 27) (n = 75) Desnuelle (1959). All measurements of enzyme Protein (mg/ml) 0- 7 + 0-32 23-5 ± 5-3 11-5 + 10.2 activities were made at 25°C. Calcium (m-equiv/l) 0.79 ± 0.13 2-85 + 0-86 1.82 ± 1-0 Coefficient of http://gut.bmj.com/ The BAEE was purchased from Serva Labora- correlation r + 0409 + 0-826 tories, Heidelberg, enterokinase from Koch and Light Laboratories, England, all the other chemicals Table I Concentrations ofprotein and ofcalcium were obtained from Merck, Darmstadt. in pancreatic juice ofdogs after infusion ofsecretin and superimposed stimulation with pancreozymin- 'Cecekin, Karolinska Institut, Stockholm. cholecystokinin 100- on September 27, 2021 by guest. Protected copyright. |- S E C R E T I N - INFUSION PANCREOZYMIN V co- 2,5 U/kg *0- 20- ,........... 10- ,. .... N- 6- Fig. 1 Standard experiment. ........ Effect of a double stimulation with pancreozymin on the output ofprotein and calcium 2. PROTEIN in pancreatic juice of a dog. 1 as 0.6 Ok Calcium/...., 02 PENTOBARBITAL ANAESTHESIA * 25mg/kg-..W.v 20 io ~~~~~~~~~~~~~~~~~~~~~....__........ib do 169 iio 1t'o ' lio tio M,in AO Gut: first published as 10.1136/gut.13.6.477 on 1 June 1972. Downloaded from Stimulatory effect ofpancreozymin-cholecystokinin on calcium secretion in pancreatic juice of dogs 479 V PANCREOZYMIN ( 2.5 U/kg) V PANCREOZYMIN Fig. 2 Concentrations of POTA^ S S U M calcium, protein, trypsin, sodium, and potassium in pancreatic juice ofa dog, stimulated twice by injections ofpancreozymin. In the N8 CALCIUM secondpart of this standard (meq/) experiment anaesthesia was ZI&A * induced with pentobarbital. PROTEIN YPSIN b (U/ml) 30 m9g /kg men 1180 http://gut.bmj.com/ Fig. 3 Effect ofsecretin infusion with different doses on the volume and the concentration of calcium andprotein in pancreatic juice ofa dog. Anaesthesia with pentobarbital. on September 27, 2021 by guest. Protected copyright. of 0.7 ± 0-32 mg/ml. During the transition from the infusion of 2 units/kg/hr of secretin. The concentra- conscious state to pentobarbital-induced sleep the tions of sodium and potassium were found in the protein concentration was observed to fall to about range of serum values and were not influenced 014-02 mg/ml, without variation in the calcium significantly by secretin infusion. concentration (Fig. 2). Figure 3 gives an example of the influence of a stepwise increase in the dosage of STIMULATION WITH PANCREOZYMIN- infused secretin on flow rate and on calcium and CHOLECYSTOKININ protein concentration in the juice. The volume As shown in the standard experiment of Fig. produced reached a plateau at 2 clinical units/kg/hr. 2, the injection of 2-5 units/kg pancreozymin- Calcium and protein concentrations in the juice cholecystokinin (CCK) induced a sharp increase in were found to decrease, and then to remain stable at the concentrations of both calcium and protein. The relatively low values after about half an hour of activities of trypsin and lipase were strictly pro- Gut: first published as 10.1136/gut.13.6.477 on 1 June 1972. Downloaded from 480 H. Goebell, Ch. Steffen, and Ch. Bode portional to the protein concentration. The basal decline of protein and calcium concentration evoked levels were reached again during the following 50 by CCK is calculated. It now becomes evident that minutes. A second stimulation with a similar dose the calcium concentration in all phases of the experi- of CCK 90 minutes later under pentobarbital an- ment runs parallel to the concentration of enzyme aesthesia was promptly followed by another parallel protein.
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