The action of magnesium upon stimulus-secretion coupling in the exocrine pancreas
type: CreativeWork
description: I. Investigations were carried out to establish (a) the regulation of magnesium homeostasis in the exocrine pancreas under agonist stimulation (b) that secretagogueevoked cellular processes in the exocrine pancreas are sensitive to physiological changes in Mg2+ and (c) the intracellular roles of Mg2+ in the secretagogue-evoked exocytotic processes in the exocrine pancreas. H. CCK8 and ACh can induce a dose-dependent transmembrane efflux of Mg2+ which results in a subsequent lowering of [M g2+] . The routes for movement of Mg2+ do not appear to be associated with those sites of Ca2+ mobilisation from either the internal Ca2+ stores or across cell membranes but appears to be associated with those of Na+ and is ATP-dependent. Stimulation with secretin results in an elevation of [Mg2+] compared to resting values. The secretin-evoked elevation of [Mg2+] may be coupled to G protein activation of adenylate cyclase. Digital imaging technology further demonstrates that mobilisation of Mg2+ follows a different route from that of Ca2 . The CCK8-evoked Ca2 signal is initiated in an area towards the luminal pole of the pancreatic acini and rapidly spreads throughout the entire cell. Stimulation of single pancreatic acini with CCK8 results in an initial transient increase in [Mg 2 ] throughout the entire cell which is followed by a sustained decrease in [Mg2+] which is more prominent around the basolateral membrane. III. Pertubations in extracellular and intracellular Mg2+ had marked effects on the CCK5- and secretin-evoked pancreatic juice flow and protein output in (a) the isolated perfused intact pancreas, and (b) amylase release in pancreatic segments and permeabilised pancreatic acini. A nominally Mg2+ deficient saline augments the CCK8-induced responses, whereas elevated Mg2+ attenuated secretion compared to normal (1.0 mM) Mg2 conditions. Parallel effects were found on Ca 2 mobilisation in Fura 2 loaded acini suspensions and on oscillations of Ca2+ in single acini stimulat…
abstract: I. Investigations were carried out to establish (a) the regulation of magnesium homeostasis in the exocrine pancreas under agonist stimulation (b) that secretagogueevoked cellular processes in the exocrine pancreas are sensitive to physiological changes in Mg2+ and (c) the intracellular roles of Mg2+ in the secretagogue-evoked exocytotic processes in the exocrine pancreas. H. CCK8 and ACh can induce a dose-dependent transmembrane efflux of Mg2+ which results in a subsequent lowering of [M g2+] . The routes for movement of Mg2+ do not appear to be associated with those sites of Ca2+ mobilisation from either the internal Ca2+ stores or across cell membranes but appears to be associated with those of Na+ and is ATP-dependent. Stimulation with secretin results in an elevation of [Mg2+] compared to resting values. The secretin-evoked elevation of [Mg2+] may be coupled to G protein activation of adenylate cyclase. Digital imaging technology further demonstrates that mobilisation of Mg2+ follows a different route from that of Ca2 . The CCK8-evoked Ca2 signal is initiated in an area towards the luminal pole of the pancreatic acini and rapidly spreads throughout the entire cell. Stimulation of single pancreatic acini with CCK8 results in an initial transient increase in [Mg 2 ] throughout the entire cell which is followed by a sustained decrease in [Mg2+] which is more prominent around the basolateral membrane. III. Pertubations in extracellular and intracellular Mg2+ had marked effects on the CCK5- and secretin-evoked pancreatic juice flow and protein output in (a) the isolated perfused intact pancreas, and (b) amylase release in pancreatic segments and permeabilised pancreatic acini. A nominally Mg2+ deficient saline augments the CCK8-induced responses, whereas elevated Mg2+ attenuated secretion compared to normal (1.0 mM) Mg2 conditions. Parallel effects were found on Ca 2 mobilisation in Fura 2 loaded acini suspensions and on oscillations of Ca2+ in single acini stimulat…
author: Wisdom, Denham Maynard
language: en
keywords: F410 - Forensic science
date published: 1994-05
date modified: 2026-07-24T01:36:03Z
provider: University of Central Lancashire
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Central Lancashire