Comparison of the Inhibitory Effects of Interferons-α and -γ on Testosterone Production in Porcine Leydig Cell Culture

In porcine Leydig cell culture, incubation with natural or recombinant human interferon-alpha (IFN-alpha), or recombinant porcine IFN-gamma preparations were effective in inhibiting basal and human chorionic gonadotropin (hCG)-stimulated testosterone production in a dose-dependent manner. Combined treatment with any of the human IFN-alpha preparations plus recombinant porcine IFN-gamma at the maximal inhibitory dose (1,000 pmoles/liter) further increased the inhibitory effect of any single IFN preparation on hCG-stimulated testosterone production. These results show that in porcine Leydig cells, both human IFN-alpha and porcine IFN-gamma are able to inhibit testosterone production and that the inhibitory action can be enhanced significantly by combined treatment with these types of IFNs. The enhancement of the inhibitory effect by combined treatment is consistent with the known presence of distinct cell membrane receptors for IFN-alpha and IFN-gamma.