Abstract
The developmental plaarmacology of endotoxin (Escherichia coli UKT-b) inthe rabbit was studied. When newborn rabbits were kept at a high ambient temperatureat which its basal metabolism was considered minimal, a small but definite febrile responsewas observed to endotoxin administered intravenously (0.5 pg/kg), subcutaneously (l pg/kg)or intracisternally (0.1 ng/kg). At room temperature (25C), such a significant febrileresponse was not observed. The febrile response increased in magnitude with the advancein age. Susceptibilities to the lethal effect of intravenous or intracisternal endotoxin werehigh in rabbits from the lst to 3rd day of life. They decreased over a period from the 7thto 21st day of life. Thereafter, tltey increased with the advance in age. Neither skinreaction nor shock by endotoxin was observed in rabbits under 21 days of age. Theseresults suggested that the receptor-effector mechanisms to endotoxin might be developedfairly in the CNS, but very poorly in the peripheral organs of rabbits in the early postnatal age.
