CAMP ACTIVATES MAGNESIUM EFFLUX VIA THE NA MG ANTIPORTER IN ASCITES-CELLS/

In intact ascites cells magnesium efflux is substantially stimulated b y cAMP analogues and by low concentrations of prostaglandins (PGE(1) a nd PGE(2)) which increases the synthesis of cAMP. cAMP stimulates magn esium efflux by directly stimulating the Na-Mg antiporter rather than determining a magnesium release from mitochondria as reported for othe r cell types. Protein kinase inhibitors abolish the cAMP stimulated ma gnesium efflux suggesting that the stimulation is mediated by the phos phorylation of the carrier protein, increasing its affinity for intrac ellular magnesium. These data provide evidence that receptor-mediated stimuli eventually leading to cell activation are directly connected t o the regulation of intracellular magnesium. (C) 1994 Academic Press, Inc.