Advanced

The method of administration of cholecystokinin determines the effects evoked in the pancreas

Ohlsson, Bodil LU ; Van der Borght, Karin LU ; Rehfeld, Jens; Axelson, Jan LU and Sundler, Frank LU (2001) In Pancreas 23(1). p.94-101
Abstract
Earlier studies have shown different effects on cell proliferation and weight characteristics by sulfated cholecystokinin-8 (CCK-8S) in the rat pancreas when the peptide has been administered continuously rather than intermittently. The aim of this study was as follows: (i) to compare the effect of continuous infusion and of intermittent injections of CCK-8S on cell proliferation, weight gain, and induction of apoptosis and (ii) to examine the effect of injections of CCK-8S on CCK-A receptor gene expression in the rat pancreas. Male Sprague-Dawley rats had subcutaneous continuous infusion of CCK-8S in a dose of 5 microg/kg/h or 1% bovine serum albumin (BSA) (vehicle) by implanted osmotic minipumps. The rats were killed after 4 days. Other... (More)
Earlier studies have shown different effects on cell proliferation and weight characteristics by sulfated cholecystokinin-8 (CCK-8S) in the rat pancreas when the peptide has been administered continuously rather than intermittently. The aim of this study was as follows: (i) to compare the effect of continuous infusion and of intermittent injections of CCK-8S on cell proliferation, weight gain, and induction of apoptosis and (ii) to examine the effect of injections of CCK-8S on CCK-A receptor gene expression in the rat pancreas. Male Sprague-Dawley rats had subcutaneous continuous infusion of CCK-8S in a dose of 5 microg/kg/h or 1% bovine serum albumin (BSA) (vehicle) by implanted osmotic minipumps. The rats were killed after 4 days. Other rats were either injected subcutaneously only once or injected twice daily for 3 days with either 6 microg of CCK dissolved in 0.5 mL BSA or 0.5 mL BSA alone. The rats were killed 1, 3, 6, and 12 hours after the last injection. One hour before death they received 5-bromo-2-deoxyuridine (BrdU) intraperitoneally to localize and quantitate the cell proliferation. Plasma was collected for analysis of CCK. The pancreas was dissected and immunohistochemistry was performed for analysis of the expression of the apoptosis promoting protein bax and the apoptosis inhibiting protein bcl-2, and for BrdU and CCK-A receptor localization. In situ hybridization (ISH) was used for examination and semiquantification of CCK-A receptor mRNA expression. Continuous infusion of CCK-8S led to a sixfold increase in plasma CCK and a 40% increase in pancreatic weight without any effect on BrdU labeling. Immunohistochemistry revealed decreased tissue expression of bax but unaffected expression of bcl-2. Intermittent injections of CCK-8S led to hyper-CCK-emia with increased incorporation of BrdU, indicating increased cell proliferation but no increase in pancreatic weight. Immunohistochemistry showed increased expression of bax, whereas bcl-2 remained unchanged. Immunofluorescence and ISH for the CCK-A receptor and its gene expression, respectively, showed a lowest intensity at 3 hours after CCK-8S injections. The results indicate that decreased apoptosis could explain the increased pancreatic weight during continuous infusion of CCK-8S. An increased apoptosis could explain the lack of pancreatic weight gain upon intermittent injections of CCK-8S despite the stimulation of cell proliferation. Injections of CCK-8S only transiently decreased the tissue levels of its receptor. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cholecystokinin, CCK-A receptor, Receptor regulation, Pancreas, Apoptosis, bax, bcl-2
in
Pancreas
volume
23
issue
1
pages
94 - 101
publisher
Lippincott Williams & Wilkins
external identifiers
  • pmid:11451154
  • scopus:0034951089
ISSN
0885-3177
language
English
LU publication?
yes
id
337eb841-9498-4395-9e07-557a6cc29a6f (old id 1119839)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/11451154
date added to LUP
2008-07-09 08:41:53
date last changed
2018-01-07 05:15:23
@article{337eb841-9498-4395-9e07-557a6cc29a6f,
  abstract     = {Earlier studies have shown different effects on cell proliferation and weight characteristics by sulfated cholecystokinin-8 (CCK-8S) in the rat pancreas when the peptide has been administered continuously rather than intermittently. The aim of this study was as follows: (i) to compare the effect of continuous infusion and of intermittent injections of CCK-8S on cell proliferation, weight gain, and induction of apoptosis and (ii) to examine the effect of injections of CCK-8S on CCK-A receptor gene expression in the rat pancreas. Male Sprague-Dawley rats had subcutaneous continuous infusion of CCK-8S in a dose of 5 microg/kg/h or 1% bovine serum albumin (BSA) (vehicle) by implanted osmotic minipumps. The rats were killed after 4 days. Other rats were either injected subcutaneously only once or injected twice daily for 3 days with either 6 microg of CCK dissolved in 0.5 mL BSA or 0.5 mL BSA alone. The rats were killed 1, 3, 6, and 12 hours after the last injection. One hour before death they received 5-bromo-2-deoxyuridine (BrdU) intraperitoneally to localize and quantitate the cell proliferation. Plasma was collected for analysis of CCK. The pancreas was dissected and immunohistochemistry was performed for analysis of the expression of the apoptosis promoting protein bax and the apoptosis inhibiting protein bcl-2, and for BrdU and CCK-A receptor localization. In situ hybridization (ISH) was used for examination and semiquantification of CCK-A receptor mRNA expression. Continuous infusion of CCK-8S led to a sixfold increase in plasma CCK and a 40% increase in pancreatic weight without any effect on BrdU labeling. Immunohistochemistry revealed decreased tissue expression of bax but unaffected expression of bcl-2. Intermittent injections of CCK-8S led to hyper-CCK-emia with increased incorporation of BrdU, indicating increased cell proliferation but no increase in pancreatic weight. Immunohistochemistry showed increased expression of bax, whereas bcl-2 remained unchanged. Immunofluorescence and ISH for the CCK-A receptor and its gene expression, respectively, showed a lowest intensity at 3 hours after CCK-8S injections. The results indicate that decreased apoptosis could explain the increased pancreatic weight during continuous infusion of CCK-8S. An increased apoptosis could explain the lack of pancreatic weight gain upon intermittent injections of CCK-8S despite the stimulation of cell proliferation. Injections of CCK-8S only transiently decreased the tissue levels of its receptor.},
  author       = {Ohlsson, Bodil and Van der Borght, Karin and Rehfeld, Jens and Axelson, Jan and Sundler, Frank},
  issn         = {0885-3177},
  keyword      = {Cholecystokinin,CCK-A receptor,Receptor regulation,Pancreas,Apoptosis,bax,bcl-2},
  language     = {eng},
  number       = {1},
  pages        = {94--101},
  publisher    = {Lippincott Williams & Wilkins},
  series       = {Pancreas},
  title        = {The method of administration of cholecystokinin determines the effects evoked in the pancreas},
  volume       = {23},
  year         = {2001},
}