Activation of Na+/Mg2+ antiport in thymocytes by cAMP.
Mg2+ efflux from Mg(2+)-loaded rat thymocytes was stimulated by 0.1 mM dibutyryl cAMP (db cAMP). The activation of Mg2+ efflux by db cAMP was more expressed at lower Mg(2+)-loading. cAMP induced only a very small increase in the concentration of intracellular free Mg2+ which cannot explain the activation of Na+/Mg2+ antiport. From these results it was concluded that cAMP increases the affinity of the Na+/Mg2+ antiporter for intracellular Mg2+, probably by phosphorylation.
Günther
T
T
Institute of Molecular Biology and Biochemistry, Free University of Berlin, Germany.
Vormann
J
J
D000818:Animals; D001692:Biological Transport; D003994:Bucladesine / Q000494:pharmacology*; D002412:Cations; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000494:pharmacology*; D008274:Magnesium / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D002412:Cations; D003994:Bucladesine; D012964:Sodium; D000242:Cyclic AMP; D008274:Magnesium