An investigation of the distribution of gastrin-like activity, and its nature, in the gastrointestinal tract of the sheep
type: CreativeWork
description: Using a modification of the extraction procedure of Gregory and Tracy (1964), and a perfused rat stomach bioassay, gastrin-like activity has been located in the ovine rumen, reticulum, omasum, abomasal body, antrum, duodenum and caecum. The antrum showed the highest concentration of gastrin-like activity, but substantial concentrations were found in the rumen, reticulum, omasum and caecum and proximal duodenum declining progressively with distance from the pylorus. A lesser concentration occurred in the abomasal body. Consideration of the relative total content of gastrin-like activity showed that the amount of extra-antral activity was substantial. The active principle was unlikely to have been cholecystokinin as the extracts had isoelectric points of a more acidic nature than that of cholecystokinin. Similarly, bioassay using an isolated guinea-pig ileum showed histamine to be absent from the extracts. Extraction of rumenal, reticular, omasal, abomasal body and antral mucosa and muscle separately showed that the gastrin-like activity resided almost completely in the mucosa. An investigation of the gastrin-like activity of air dried and freeze dried extracts showed that the freeze dried extracts were approximately 50% more active than the air dried extracts. Bioassay of a freeze dried antral extract over a twenty four week period showed that the activity was maintained for the initial six weeks, and that 80% of the activity was then lost over the following eighteen weeks. Studies using columns of Sephadex have shown that extracts from all regions of the ovine gastro-intestinal tract investigated were similar and consisted of several components of differing molecular weight. By a comparison of their respective molecular weights, to those reported for components separated from extracts of non-ruminant origin, it seems likely that components corresponding to MG, HLG, BG, BBG and component I were present in varying amounts. The response to infusions of gastrin extract …
abstract: Using a modification of the extraction procedure of Gregory and Tracy (1964), and a perfused rat stomach bioassay, gastrin-like activity has been located in the ovine rumen, reticulum, omasum, abomasal body, antrum, duodenum and caecum. The antrum showed the highest concentration of gastrin-like activity, but substantial concentrations were found in the rumen, reticulum, omasum and caecum and proximal duodenum declining progressively with distance from the pylorus. A lesser concentration occurred in the abomasal body. Consideration of the relative total content of gastrin-like activity showed that the amount of extra-antral activity was substantial. The active principle was unlikely to have been cholecystokinin as the extracts had isoelectric points of a more acidic nature than that of cholecystokinin. Similarly, bioassay using an isolated guinea-pig ileum showed histamine to be absent from the extracts. Extraction of rumenal, reticular, omasal, abomasal body and antral mucosa and muscle separately showed that the gastrin-like activity resided almost completely in the mucosa. An investigation of the gastrin-like activity of air dried and freeze dried extracts showed that the freeze dried extracts were approximately 50% more active than the air dried extracts. Bioassay of a freeze dried antral extract over a twenty four week period showed that the activity was maintained for the initial six weeks, and that 80% of the activity was then lost over the following eighteen weeks. Studies using columns of Sephadex have shown that extracts from all regions of the ovine gastro-intestinal tract investigated were similar and consisted of several components of differing molecular weight. By a comparison of their respective molecular weights, to those reported for components separated from extracts of non-ruminant origin, it seems likely that components corresponding to MG, HLG, BG, BBG and component I were present in varying amounts. The response to infusions of gastrin extract …
author: Jury, Denis R.
license: https://researchcommons.waikato.ac.nz/bitstreams/e1034ae0-cda1-4486-9d48-36c5982281e9/download
date published: 1978
date modified: 2026-07-24T05:57:21Z
provider: University Waikato
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: The University of Waikato