Interleukin-1 beta regulates nitric oxide production and gamma-glutamyl transpeptidase activity in Sertoli cells

Several cytokines have been involved in the regulation of Sertoli cell func tion. Further investigations are required to elucidate the role of interleu kin-1 beta (IL1 beta) in Sertoli cell physiology. Twenty-day-old rat Sertol i cell cultures were used to investigate a possible role of IL1 beta in the regulation of gamma -glutamyl transpeptidase (gamma GTP) and to elucidate the signaling pathway utilized by this cytokine. gamma GTP is a membrane-bo und enzyme that has been involved in amino acid transport across the plasma membrane and in protection from oxidative stress through its importance in the regulation of glutathione levels. Previous studies suggested that IL1 beta stimulates NO biosynthesis in other cell types. Therefore, we investig ated whether IL1 beta modified the level of nitrite, a stable metabolite of NO, in Sertoli cells. Dose-response curves to IL1 beta for gamma GTP activ ity and nitrite production were observed. The increments observed in gamma GTP activity and nitrite production were partially and completely blocked b y simultaneous treatment with the NO synthase inhibitor aminoguanidine. Tre atment of Sertoli cell cultures with the NO donors sodium nitroprusside and S-nitroso-N-acetylpenicillamine resulted in an increase in gamma GTP activ ity. The presence of neural, endothelial, and inducible isoforms of NO synt hase (NOS) was investigated by a immunohistochemical technique using specif ic antibodies. The 2 constitutive isoforms were present under basal conditi ons, and the inducible protein appeared in IL1 beta -treated cultures. Fina lly, translocation of NF-kappaB p65 subunit to the nucleus in IL1 beta -tre ated cultures was observed. These findings suggest that the action of IL1 b eta on Sertoli cell gamma GTP activity is partially mediated via activation of NF-kappaB and increments in iNOS and cellular production of NO.