The experiments concerned the effects of beta-adrenoceptor agonists and antagonists on the leukotriene-C4 (LTC4)-induced secretory release response from carrageenan-elicited rat peritoneal macrophages. Both the non-selective beta-adrenoceptor agonist isoprenaline and the selective beta 2-adrenoceptor agonist salbutamol reversed the LTC4-induced release response. Addition of the non-selective beta-adrenoceptor antagonist sotalol or the beta 2-selective antagonist H3525 abolished these effects. Practolol, a selective beta 1-adrenoceptor antagonist was without any effect on the isoprenaline-LTC4 interaction. These results are consistent with the presence of beta 2-adrenoceptors on macrophages. The results of this study are discussed in view of a possible, cyclic adenosine 3'5'-monophosphate (cAMP)-mediated interaction between prostaglandin E2 and LTC4 in modulating macrophage function.