Diurnal factors influence the metabolic response to endotoxins

Abstract

Rats were injected with trichloroacetic acid or butanol extracts of E.coli endotoxin during the resting or active phases of their daily life cycle. Changes in body temperature, elevation of corticosterone, depression of serum zinc, gain in liver protein and loss of muscle protein and skin weight occurred. While the butanol extract of endotoxin produced a small fever and the trichloroacetic acid extract a transient hypothermia during the resting phase, both types of endotoxin produced hypothermia during the active phase of the daily life cycle. The degree of hypothermia and depression of serum zinc were significantly correlated. Responsiveness to endotoxin is greatest during the active part of the daily life cycle.