Temporal expression of tumor necrosis factor-alpha and nitric oxide synthase 2 in rat small intestine after endotoxin.

Temporal changes in tumor necrosis factor-alpha (TNF-alpha) and nitric oxide synthase 2 (NOS 2) were evaluated in segments of duodenum, jejunum, and ileum removed from male Sprague-Dawley rats 30, 60, 120, 180, and 240 min after lipopolysaccharide (LPS), 5 mg/kg, intraperitoneally. Plasma was assayed for TNF-alpha and for nitrate/nitrite (NOx). Intestinal and plasma TNF-alpha were elevated by 60 min after LPS and were back to control levels by 180 min. For control rats, NOS 2 was detected in the ileum, but not in the duodenum or the jejunum. In rats treated with LPS, NOS 2 was detected in all areas of the intestine at 120 min and was greatest at 240 min. Plasma NOx was elevated at 120 min and continued to increase to 240 min. The time course of changes in intestinal TNF-alpha and NOS 2 were similar to those reported for other tissues and suggest that the early and late actions of the LPS on the intestine may involve both mediators.