Background: Sex hormones have profound effects on immune responses andmay influence the disease which caused by intracellular parasite(Leishmania) and bacterial (tuberculosis)andalso autoimmune disease such as rheumatoid arthritis (RA). It has also been demonstrated that 5α-Dihydrotestosterone(5α-DHT) modulate nitric oxide and cytokine release by macrophages. These effects seem to be exertedby specific receptors for androgen in macrophages. Material/Methods: Protein secretion: The effect of5α-DHT on protein secretion by peritoneal macrophages of NZBBALBc mice was investigated using radiolabelledprotein secretion following SDS-PAGE and Fluorography. Binding Assay: Androgen binding was also investigatedusing an autoradiography method. Peritoneal macrophages were treated with [[sup]3[/sup]H]- 5α-DHT and incubatedfor 2 h before smearing on to microscope slides. Slides were air dried, dipped in Kodak NTB photographicemulsion, sealed in light proof boxes and left at 4 degrees C for 6 weeks. Results: The results showedthat protein secretion by macrophages changed under 5α-DHT treatment. Analysis of the data accordingto quantitation of [[sup]3[/sup]H]-5αDHT binding receptors in fixed-slide mounted cells, identified a highspecific androgen binding at physiological concentration. The receptors had a relatively high affinityfor the 5α-DHT, So that binding affinity was not inhibited in the presence of 100-fold excess ofnon labelled 17-β Estradiol. Conclusions: These results suggest that the immunosuppressive actionexerted by androgen is at least partially achieved through a direct influence on macrophages.

Keywords: Androgens - pharmacology, Autoradiography, Dihydrotestosterone - pharmacology, Estradiol - metabolism, Macrophages, Peritoneal - metabolism, Radioligand Assay, Receptors, Androgen - metabolism