[Effect of x-irradiation, nicotinic acid and neostigmine methylsulfate on the interrelation between methylation and biosynthesis of tRNA].

Experiments on rats established that tRNA of the liver under the effect of total X-irradiation (800 R), nicotinic acid and neostigmine methylsulphate proves to be hypermethylated. In this case tRNA molecules undergo conformation changes. Nicotinic acid and neostigmine methylsulphate administered to the animals under experiment an hour before irradiation favour the normalization of these indexes. As a rule, a correlation is observed between changes in methylation of tRNA and activity of their methylases. Irradiation inhibits the processes of tRNA synthesis which are normalized under the effect of nicotinic acid administered before the irradiation. Nicotinic acid and neostigmine methylsulphate produce no effect on synthesis of tRNA in the liver of normal animals. The activity of acid tRNase under the effect of nicotinic acid is not changed, under other conditions of the experiment it decreases. Irradiation against a background of nicotinic acid and neostigmine methylsulphate administered to animals and neostigmine methylsulphate administration to the intact animals inhibit the activity of alkaline tRNase.