RESUMEN
We studied the age-related features of circadian rhythms of superoxide dismutase (SOD) and catalase activity in the liver of rats under light deprivation. In standard light conditions (LD), significant daily fluctuations in SOD activity with a maximum at 07:00 am was detected only in young animals (1,5 months) but catalase activity was observed in young (1,5 months) and in adults (7,5 months) with peak at 04:00 am. The daily dynamics of total and specific activity of SOD and catalase in the liver in young and adult rats differed depending on the period of ontogeny in which the impact of light deprivation began. When the females and offspring were moved to darkness after birth (group LD/DD), the circadian rhythms of SOD and catalase activitys were observed in young and were absent in adult rats. However, circadian rhythms of the antioxidant enzymes (AOE) activities were inherent only adult rats when light deprivation impacted on pregnant females (group DD/DD). Changes in circadian rhythms under light deprivation were characterized either by a phase shift of the enzymes activity (in the LD/DD group) or by a violation of their develpoment in ontogeny (in the DD/DD group). During aging significant decreasing of catalase activity was compensated by an increase in the amplitude of circadian rhythms of activity of this enzyme in animals of all groups. A distinctive feature of daily fluctuations in AOÐ activity in young rats in LD and LD/DD groups can be considered the presence of an ultradian rhythm in the general circadian cycle, which had a second peak with a smaller amplitude and shorter period.
