Possible differences in the mechanism(s) of action of different glucocorticoid hormone compounds.

Different glucocorticoid hormones (GCH) show differences in the intensity and in the kinetics of their immunomodulating activity. The mechanism(s) of action of GCH is under investigation, but is has been noted that they exert immune activity via the genomic pathway. We have studied the effects of prednisone (PDN), deflazacort (DFC), and dexamethasone (DXM) on the production of cytokines (IL-2, IL-6, TNF-alpha, IL-10) by peripheral T lymphocytes, and the effects on the inhibition of NF-kB DNA binding activity by activated Jurkat cell line. The data obtained show that the three GCH molecules exert an immunosuppression on cytokine production by T lymphocytes and a strong decrease in the nuclear translocation of NF-kB in Jurkat cells; moreover, (a) not all the cytokines investigated were affected, and not with the same intensity, by the three GCH and (b) DXM inhibited the binding activity of NF-kB less than that of DFC and PDN. These data are in agreement with the concept that different GCH compounds might differ in their binding and affinity properties, tissue-specific metabolism, and interaction with transcription factor.