In the present study, we investigated the effects of some anti-asthmatic drugs on the production of the CC chemokine, macrophage inflammatory protein-1 alpha (MIP-1 alpha), in response to lipopolysaccharide (LPS) by peripheral blood mononuclear cells (PBMC). MIP-1 alpha production was induced by LPS in a concentration-dependent fashion and reached the maximum at 10 micrograms/ml LPS (27.5 +/- 2.3 ng MIP-1 alpha/10(6) PBMC). At a submaximal concentration of LPS (1 microgram/ml), the release of MIP-1 alpha increased with time and reached the maximum 24 h after LPS stimulation. Actinomycin D and cycloheximide inhibited MIP-1 alpha production completely, but glucocorticoids did not completely inhibit MIP-1 alpha production, with a maximum inhibition of 70%. We examined the effect of beta-stimulants and phosphodiesterase inhibitors, which upregulate intracellular cyclic AMP levels, on MIP-1 alpha production. When PBMC were treated with beta-stimulants alone, beta-stimulants showed a slightly inhibitory effect on MIP-1 alpha production. However, the coadministration of roliplam significantly potentiated the inhibitory effect of beta-stimulants on MIP-1 alpha production. Moreover, db-cAMP suppressed MIP-1 alpha production dose-dependently. The above data indicate that the production of MIP-1 alpha is regulated by cyclic AMP and that cyclic AMP could provide a useful target for therapeutic treatment in asthmatic diseases and other diseases where MIP-1 alpha is involved in their etiology.