Effect of different lighting conditions on beta-acetylglucosaminidase activity changes in mouse liver as related to...

The effect of a 30-minute light stimulus applied at various times of the 24-hour cycle on changes in the activity of beta-acetylglucosaminidase was studied in the liver of male mice. The animals were kept in darkness with the light switched on for 30 minutes from 9 to 9.30 a.m. in two experimental groups and from 9 to 9.30 p.m. in another two groups. The total beta-acetylglucosaminidase activity in the homogenate was determined by the method of Sellinger et al. at intervals of 4 hours after 1 and 4 weeks of this experiment. At the same time, in all groups the locomotor activity of the animals was recorded. The obtained results showed that: 1) under the conditions of this experiment rhythmic changes of beta-acetylglucosaminidase activity persisted evidencing their endogenous origin; 2) the effect produced by light depended on the time of the 24-hour period at which it was applied; 3) the rhythm of locomotor activity seems to be synchronized directly by the light-darkness changes.