INCREASED LEVELS OF ADENOSINE 3',5'-CYCLIC-MONOPHOSPHATE IN TETRAHYMENA STIMULATED BY GLUCOSE AND MEDIATED BY CA-2+ AND EPINEPHRINE

Stationary phase Tetrahymena cells exposed to 0.5-1% glucose experience and 8-fold increase in intracellular cyclic[c]AMP within 1 h. The increase follows an enhanced uptake of Ca2+ triggered by the glucose addition. Inhibiting the Ca2+ influx with ethylene glycol bis(.beta.-aminoethyl ether)-N,N,N'',N''-tetraacetic acid blocks the increase in cAMP, but the block can be reversed by the addition of epinephrine. The epinephrine effect and the glucose-induced increase in cAMP are counteracted by the .beta.-adrenergic inhibitor dichloroisoproterenol.