Evidence for a regulatory loop between cholecystokinin (CCK) and tryptic enzyme activity in Atlantic cod larvae (Gadus morhua)
In order to maximize protein digestion, the release of enzymes into the gut lumen is closely controlled by a regulatory loop. Cholecystokinin (CCK) is among the enteric hormones that play a key role in the control of digestive enzyme secretion, but its role in first-feeding larvae is still unclear a...
Published in: | Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology |
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Format: | Article in Journal/Newspaper |
Language: | English |
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Online Access: | https://oceanrep.geomar.de/id/eprint/22070/ https://oceanrep.geomar.de/id/eprint/22070/1/1-s2.0-S1095643313002080-main.pdf https://doi.org/10.1016/j.cbpa.2013.08.001 |
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ftoceanrep:oai:oceanrep.geomar.de:22070 2023-05-15T15:27:47+02:00 Evidence for a regulatory loop between cholecystokinin (CCK) and tryptic enzyme activity in Atlantic cod larvae (Gadus morhua) Tillner, Robert Rønnestad, Ivar Harboe, Torstein Ueberschär, Bernd 2013-11-01 text https://oceanrep.geomar.de/id/eprint/22070/ https://oceanrep.geomar.de/id/eprint/22070/1/1-s2.0-S1095643313002080-main.pdf https://doi.org/10.1016/j.cbpa.2013.08.001 en eng Elsevier https://oceanrep.geomar.de/id/eprint/22070/1/1-s2.0-S1095643313002080-main.pdf Tillner, R., Rønnestad, I., Harboe, T. and Ueberschär, B. (2013) Evidence for a regulatory loop between cholecystokinin (CCK) and tryptic enzyme activity in Atlantic cod larvae (Gadus morhua). Comparative Biochemistry and Physiology Part A: Molecular and Integrative Physiology, 166 (3). pp. 490-495. DOI 10.1016/j.cbpa.2013.08.001 <https://doi.org/10.1016/j.cbpa.2013.08.001>. doi:10.1016/j.cbpa.2013.08.001 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2013 ftoceanrep https://doi.org/10.1016/j.cbpa.2013.08.001 2023-04-07T15:10:22Z In order to maximize protein digestion, the release of enzymes into the gut lumen is closely controlled by a regulatory loop. Cholecystokinin (CCK) is among the enteric hormones that play a key role in the control of digestive enzyme secretion, but its role in first-feeding larvae is still unclear and may differ between species. However, in all marine fish larvae that have not developed a stomach by first-feeding, trypsin is the most important proteolytic enzyme. In order to examine the regulation and feedback mechanisms in the gut of larval cod, we therefore studied the interactions between cholecystokinin and tryptic enzyme activity following the administration of solutions containing test substances directly into the gut. We tube-fed a single dose of physiological saline solution containing either CCK, CCK antagonist, trypsin inhibitor, phytohemagglutinin (PHA; a possible trigger for the digestive response) or physiological saline alone, while a further control group was left untreated. We then followed the response in CCK and tryptic enzyme activity for 0.5–8 h after the administration. We performed the experiment on larvae at 26 day post first-feeding, which is before the stomach has evolved and the size of the larvae allows easier handling. Individual larvae were analyzed for CCK and tryptic enzyme activity using radioimmunoassay and fluorimetric techniques respectively. Both factors varied over time in the untreated control group, possibly due to an endogenous daily rhythm. The higher CCK levels at 4 h and 8 h in the saline-injected group may be caused by reflexes initiated by distension of the gut. An increase in tryptic enzyme activity after injection of CCK supports the hypothesis that this hormone plays a part in the release of pancreatic enzymes in larval cod at this developmental stage. However, administration of a CCK antagonist and a trypsin inhibitor did not reveal conclusive results, probably due to the relatively low concentrations used. The response in tryptic activity in the PHA group was ... Article in Journal/Newspaper atlantic cod Gadus morhua OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 166 3 490 495 |
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Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
In order to maximize protein digestion, the release of enzymes into the gut lumen is closely controlled by a regulatory loop. Cholecystokinin (CCK) is among the enteric hormones that play a key role in the control of digestive enzyme secretion, but its role in first-feeding larvae is still unclear and may differ between species. However, in all marine fish larvae that have not developed a stomach by first-feeding, trypsin is the most important proteolytic enzyme. In order to examine the regulation and feedback mechanisms in the gut of larval cod, we therefore studied the interactions between cholecystokinin and tryptic enzyme activity following the administration of solutions containing test substances directly into the gut. We tube-fed a single dose of physiological saline solution containing either CCK, CCK antagonist, trypsin inhibitor, phytohemagglutinin (PHA; a possible trigger for the digestive response) or physiological saline alone, while a further control group was left untreated. We then followed the response in CCK and tryptic enzyme activity for 0.5–8 h after the administration. We performed the experiment on larvae at 26 day post first-feeding, which is before the stomach has evolved and the size of the larvae allows easier handling. Individual larvae were analyzed for CCK and tryptic enzyme activity using radioimmunoassay and fluorimetric techniques respectively. Both factors varied over time in the untreated control group, possibly due to an endogenous daily rhythm. The higher CCK levels at 4 h and 8 h in the saline-injected group may be caused by reflexes initiated by distension of the gut. An increase in tryptic enzyme activity after injection of CCK supports the hypothesis that this hormone plays a part in the release of pancreatic enzymes in larval cod at this developmental stage. However, administration of a CCK antagonist and a trypsin inhibitor did not reveal conclusive results, probably due to the relatively low concentrations used. The response in tryptic activity in the PHA group was ... |
format |
Article in Journal/Newspaper |
author |
Tillner, Robert Rønnestad, Ivar Harboe, Torstein Ueberschär, Bernd |
spellingShingle |
Tillner, Robert Rønnestad, Ivar Harboe, Torstein Ueberschär, Bernd Evidence for a regulatory loop between cholecystokinin (CCK) and tryptic enzyme activity in Atlantic cod larvae (Gadus morhua) |
author_facet |
Tillner, Robert Rønnestad, Ivar Harboe, Torstein Ueberschär, Bernd |
author_sort |
Tillner, Robert |
title |
Evidence for a regulatory loop between cholecystokinin (CCK) and tryptic enzyme activity in Atlantic cod larvae (Gadus morhua) |
title_short |
Evidence for a regulatory loop between cholecystokinin (CCK) and tryptic enzyme activity in Atlantic cod larvae (Gadus morhua) |
title_full |
Evidence for a regulatory loop between cholecystokinin (CCK) and tryptic enzyme activity in Atlantic cod larvae (Gadus morhua) |
title_fullStr |
Evidence for a regulatory loop between cholecystokinin (CCK) and tryptic enzyme activity in Atlantic cod larvae (Gadus morhua) |
title_full_unstemmed |
Evidence for a regulatory loop between cholecystokinin (CCK) and tryptic enzyme activity in Atlantic cod larvae (Gadus morhua) |
title_sort |
evidence for a regulatory loop between cholecystokinin (cck) and tryptic enzyme activity in atlantic cod larvae (gadus morhua) |
publisher |
Elsevier |
publishDate |
2013 |
url |
https://oceanrep.geomar.de/id/eprint/22070/ https://oceanrep.geomar.de/id/eprint/22070/1/1-s2.0-S1095643313002080-main.pdf https://doi.org/10.1016/j.cbpa.2013.08.001 |
genre |
atlantic cod Gadus morhua |
genre_facet |
atlantic cod Gadus morhua |
op_relation |
https://oceanrep.geomar.de/id/eprint/22070/1/1-s2.0-S1095643313002080-main.pdf Tillner, R., Rønnestad, I., Harboe, T. and Ueberschär, B. (2013) Evidence for a regulatory loop between cholecystokinin (CCK) and tryptic enzyme activity in Atlantic cod larvae (Gadus morhua). Comparative Biochemistry and Physiology Part A: Molecular and Integrative Physiology, 166 (3). pp. 490-495. DOI 10.1016/j.cbpa.2013.08.001 <https://doi.org/10.1016/j.cbpa.2013.08.001>. doi:10.1016/j.cbpa.2013.08.001 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.cbpa.2013.08.001 |
container_title |
Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology |
container_volume |
166 |
container_issue |
3 |
container_start_page |
490 |
op_container_end_page |
495 |
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1766358194889687040 |