Switch to
Predicate | Object |
---|---|
rdf:type | |
lifeskim:mentions | |
pubmed:issue |
4
|
pubmed:dateCreated |
1991-10-30
|
pubmed:abstractText |
In mouse thymocytes, a stereospecific saturable energy-dependent and ouabain-inhibitable system facilitates T3, but not T4, entry. We studied here the effect of sodium depletion on cellular uptake of thyroid hormones by mouse thymocytes. Time-course experiments indicated that extracellular sodium depletion reduced [125I]T3 uptake at each time studied. At equilibrium, the removal of extracellular sodium and its substitution with isoosmotic choline decreased saturable [125I]T3 uptake by 60 +/- 10%; this effect was dose dependent. The substitution of sodium with lithium, instead of choline, had no effect on the uptake process. [125I]T4 uptake was lower than that of [125I]T3 and not affected by sodium depletion. The half-maximal effect of sodium deprivation on [125I]T3 uptake was reached at an extracellular sodium concentration of about 40 mM. The variation of external pH influenced T3 accumulation by thymocytes. [125I]T3 progressively decreased from acid to alkaline pH under normal and sodium-depleted conditions; however, the sodium-dependent fraction was more than doubled at physiological pH compared to that at more acidic and more alkaline pH. The sodium ionophore monensin decreased T3 uptake by 51% at a concentration of 20 microM. These results indicated the existence of a sodium-related mechanism of T3 uptake into mouse thymocytes that does not operate for T4 uptake.
|
pubmed:language |
eng
|
pubmed:journal | |
pubmed:citationSubset |
AIM
|
pubmed:chemical | |
pubmed:status |
MEDLINE
|
pubmed:month |
Oct
|
pubmed:issn |
0013-7227
|
pubmed:author | |
pubmed:issnType |
Print
|
pubmed:volume |
129
|
pubmed:owner |
NLM
|
pubmed:authorsComplete |
Y
|
pubmed:pagination |
2175-9
|
pubmed:dateRevised |
2006-11-15
|
pubmed:meshHeading |
pubmed-meshheading:1915098-Animals,
pubmed-meshheading:1915098-Extracellular Space,
pubmed-meshheading:1915098-Hydrogen-Ion Concentration,
pubmed-meshheading:1915098-Lithium,
pubmed-meshheading:1915098-Mice,
pubmed-meshheading:1915098-Osmolar Concentration,
pubmed-meshheading:1915098-Sodium,
pubmed-meshheading:1915098-Thymus Gland,
pubmed-meshheading:1915098-Thyroxine,
pubmed-meshheading:1915098-Triiodothyronine
|
pubmed:year |
1991
|
pubmed:articleTitle |
Effect of extracellular sodium on thyroid hormone uptake by mouse thymocytes.
|
pubmed:affiliation |
Department of Experimental Medicine, University La Sapienza, Rome, Italy.
|
pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|