Induction of Hypermetabolism in Guinea Pigs by Endotoxin Infused Through the Portal Vein

Endotoxin has been suspected of inducing hypermetabolism in animals. To delineate its mechanism more precisely, three experiments were performed using male Hartley guinea pigs that involved intermittent or continuous administration of endotoxin intraperitoneally for seven days and continuous infusion of low-dose endotoxin through the portal vein for five days. The doses of endotoxin were 0.3 mg, 0.36 mg, and 0.014 mg per 100 g of body weight per day, respectively. Hypermetabolic response was induced only in the experiment involving the infusion of endotoxin through the portal vein; the hypermetabolic response was correlated significantly with endotoxin levels in the plasma. These results indicate that endotoxin translocated from the gut into the mesenteric vein will induce hypermetabolism more readily than endotoxin translocated into the peritoneal cavity.