AR and other cytokines are regulated reciprocally by cAMP signals. In contrast to the enhancement of AR expression, the cAMP agonist inhibited expression of many other cytokines ( Figure 7E ), and all four PKA-activating agents described in Figure 7 inhibited expression of IL-2 and IFNc (data not shown). These results are consistent with previous studies with cAMP agonists and natural cAMP elevating agents, such as PGE2 and adenosine [19, 20] . Thus AR expression in T cells is enhanced under conditions that suppress the production of many other cytokines.