[Effect of calorie deficient nutrition on thiol group content of liver cell nuclei from white rats of different ages].

The sulfydryl and disulfide groups content in summary histones of the hepatic cell nuclei in the Wistar albino rats aged 1, 3, 12 and 24 months was studied by employing amperometric titration under normal conditions and under the action on the organism of calorifically substandard nutrition tending to significantly prolong the life-span in these animals. In intact animals the content of thiol groups in histones was found to reach the maximum on the 3d month of their life, to continue at this level during the first year and to decline in old (34 month old) animals. In the post-natal ontogenesis of the rats the ratio of sulfhydryl to disulfide groups in the histone proteins does not show any noticeable changes. With calorific deficiency this ratio increases in histones of old animals. The possible significance of the thiol groups balance in the histone proteins in regulating the genome activity during age-dependent development of the animals is discussed.