Tumor necrosis factor-alpha in response to endotoxin administration in the pregnant guinea pig.

Objective: Our purpose was to test the hypothesis that an intramuscular endotoxin challenge induces production of tumor necrosis factor-alpha in the pregnant guinea pig and to investigate some of the metabolic effects.

Study Design: Twelve randomly selected guinea pigs at 33 days' gestation with a sampling catheter in the carotid artery received an intramuscular injection of a solution of endotoxin isolated from Bacteroides fragilis (n = 6) or of solvent alone (n = 6). Plasma values of tumor necrosis factor-alpha, hematocrit, and 6-keto-prostaglandin F1 alpha were determined before and several hours after injection.

Results: Tumor necrosis factor-alpha was detected in five of six guinea pigs, but it could not be demonstrated in five of six placebo animals. The hematocrit was significantly decreased, and prostaglandin F1 alpha significantly increased 24 to 48 hours after endotoxin injection.

Conclusion: In pregnant guinea pigs an intramuscular endotoxin challenge induces the release of tumor necrosis factor-alpha, followed by a reduced hematocrit and an increased prostacyclin concentration. These effects could be involved in the pathogenesis of endotoxin-induced fetal growth retardation.