BIOLOGIC RELATIONSHIP OF ENDOTOXIN AND OTHER TOXIC PROTEINS. III. EFFECT OF FERROUS IRON ON TOXICITY OF ENDOTOXIN AND SNAKE VENOM

Summary1. Incubation of ferrous sulfate with endotoxin for 6 hours at 37°C prior to injection did not alter the endotoxin-induced-hypersusceptibility-state (EIHS) to water moccasin venom in rabbits. 2. Incubation of ferrous sulfate with snake venom under the same conditions prior to injection gave significant protection against the lethal effects of the venom in endotoxin-pretreated rabbits. 3. Intravenous ferrous sulfate protected a significant number of animals against the lethal effects of snake venom when administered between the preparing endotoxin and the challenging dose of moccasin venom. 4. Prior intravenous ferrous sulfate also resulted in protection against an LD100 of moccasin venom in normal rabbits. 5. Finally, it was shown that administration of large, but non-toxic, doses of ferrous sulfate to endotoxin-pretreated animals resulted in the delayed death of most of the animals.