Increased levels of adenosine 3',5'-cyclic monophosphate in Tetrahymena stimulated by glucose and mediated by Ca2+ and epinephrine.

Stationary phase Tetrahymena cells exposed to 0.5-1% glucose experience an 8-fold increase in intracellular cyclic AMP within 1 hr. 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 cyclic AMP, but the block can be reversed by the addition of epinephrine. Both this epinephrine effect and the glucose-induced increase in cyclic AMP are counteracted by the beta-adrenergic inhibitor dichloroisoproterenol.