Refractoriness of the cyclic AMP response to adenosine and prostaglandin E1 in thymic lymphocytes. Dependence on protein synthesis and energy-providing substrates.

摘要: Rat thymic lymphocytes exposed to the cyclic AMP-elevating agent, adenosine, become refractory a subsequent adenosine stimulation. This refractoriness appears distinct from types of observed in other tissues. Here induction is not dependent on prior stimulus per se but rather utilization ribose moiety as an energy source. Early addition energy-providing substrates, glucose or pyruvate, instead also induces adenosine. These circumstances suggest that this instance, metabolic state cell than presence may be most important determinant. A action prostaglandin E/sub 1/ develops without exposure stimulus. However, case, rapidly even when no source provided. The data indicate for both and PGE/sub 1/, result accumulation feedback inhibitors nor, at least desensitization adenylate cyclase. In cases, development arrested by inhibiting protein synthesis with either cycloheximide emetine. While under appropriate conditions, onset fairly rapid, it does notmore » reverse quickly; partially cells leads only slight restoration responsiveness within 2 h. Although some observations synthesis-dependent widespread phenomenon, lymphoid tissues, its physiological meaning present poorly understood.« less