['Obstructive uropathy is a significant clinical problem that results in apoptotic renal cell death and progressive renal fibrosis. A number of different inflammatory mediators have been implicated in the pathophysiology of obstruction induced renal injury including tumor necrosis factor-alpha (TNF)-alpha. The cellular source of obstruction induced renal TNF-alpha production and its relationship to renal inflammatory cell infiltration remain unknown.', 'Male Sprague-Dawley rats were anesthetized and exposed to varying lengths of unilateral ureteral obstruction vs sham operation. The kidneys were harvested following renal injury and evaluated for TNF-alpha mRNA expression (reverse transcriptase polymerase chain reaction), TNF-alpha protein production (enzyme-linked immunosorbent assay), TNF-alpha cellular localization (immunohistochemistry) and leukocyte infiltration (leukocyte staining).', 'Renal TNF-alpha mRNA expression and protein production peaked following 3 days of ureteral obstruction (54 +/- 5% vs sham 22 +/- 9% of glyceraldehyde-3-phosphate dehydrogenase mRNA, p <0.05 and 204 +/- 13 vs sham 84 +/- 9 pg/ml, p <0.05, respectively). TNF-alpha production localized primarily to renal cortical tubular cells following obstruction and the time point of maximal TNF-alpha production (3 days of obstruction) were not associated with a significant renal inflammatory cell infiltrate.'] Does unilateral ureteral obstruction induce renal tubular cell production of tumor necrosis factor-alpha independent of inflammatory cell infiltration?