Linked Life Data

1690157

Source:http://linkedlifedata.com/resource/pubmed/id/1690157

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1990-4-19
pubmed:abstractText
Concentration and voltage dependence of unidirectional magnesium fluxes across the stripped mucosa of the rat terminal ileum were measured in an Ussing chamber. The mucosa-to-serosa magnesium flux exhibited a curvilinear concentration dependence, whereas serosa-to-mucosa flux of magnesium was linearly related to magnesium concentration between 0.25 and 5 mM. At low concentrations magnesium was absorbed, whereas at the magnesium concentration of 5 mM the serosa-to-mucosa magnesium flux was higher than the mucosa-to-serosa flux, resulting in magnesium secretion. Only the mucosa-to-serosa flux of magnesium had a voltage-independent (i.e., nondiffusive) cellular component. Due to the high capacity of this cellular mucosa-to-serosa transport of magnesium, which was about 7.5 times greater than that of calcium, absorption of magnesium was performed in the terminal ileum in contrast to calcium, which was secreted under the same conditions. However, magnesium serosa-to-mucosa flux was totally voltage dependent (i.e., diffusive) and probably restricted to the paracellular pathway. The diffusive serosa-to-mucosa flux of magnesium was about two times greater than the diffusive fraction of the mucosa-to-serosa transport of magnesium. The prevalence of the diffusive serosa-to-mucosa flux of magnesium over that from mucosa to serosa, responsible for magnesium secretion observed at the magnesium concentration of 5 mM, may be explained by an "anomalous solvent drag effect." Voltage clamp experiments showed that magnesium had no effect on the cellular mucosa-to-serosa transport of calcium. However, it decreased the diffusive calcium flux in this direction. 1 alpha,25-dihydroxyvitamin D3 did not influence the unidirectional or net magnesium transport but increased the calcium flux in both directions to the same degree. In conclusion, magnesium is absorbed in the terminal ileum at least partially by a cellular, vitamin D3-insensitive process that is different from the calcium transport mechanism.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0016-5085
pubmed:author
pubmed:issnType
Print
pubmed:volume
98
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
985-92
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Cellular and paracellular magnesium transport across the terminal ileum of the rat and its interaction with the calcium transport.
pubmed:affiliation
University of Munich, Medizinische Klinik Innenstadt, Homburg/Saar, Federal Republic of Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't