Temporal Variation in Hepatic Superoxide Dismutase Activity in Mice

Abstract

Circadian variations in superoxide dismutase (SOD) activity were determined in liver homogenates of Balb-C mice that were synchronized under controlled environmental conditions with 12 h light:12 h dark. The activity of hepatic SOD exhibited a significant circadian rhythm, with a minimum at 01:00 h and a maximum at 10:00-13:00 h. It is concluded that fluctuations in hepatic SOD activity render mice more susceptible to the toxic effects of reactive oxygen radicals at particular times of the day.