Macrophages are essential for the inflammatory response process because they release a wide variety of proinflammatory mediators. Endosulfan is extremely toxic to invertebrates and has been implicated in various mammalian toxicities. However, its influence on production of cytokine or on the functions of macrophages, is unclear. This study examined the effects of endosulfan on the production of nitric oxide (NO) and proinflammatory cytokines (IL-beta, IL-6, TNF-alpha), and examined the molecular mechanism in macrophages. Exposing macrophages to endosulfan induced the production of NO and proinflammatory cytokines and the expression of these genes. The transient transfection and electrophoretic mobility shift assays with the NF-KB binding sites showed that the NF-KB transcription factor mediated the endosulfan-induced increase in the expression levels of iNOS and proinflammatory cytokines. These results show that endosulfan stimulates the production of NO and proinflammatory cytokines and can up-regulate the gene expression levels through NF-KB transactivation. Overall, these results suggest that endosulfan has inflammatory potential. (c) 2007 Elsevier Inc. All rights reserved.