[Characteristics of the levels of various nucleic acid precursors in the tissues of rabbits with various thyroid conditions].

The content of the precursors and metabolites of nucleic acids in the brain and liver of normal rabbits, rabbits with hypothyrosis (thyroidectomy) and hyperthyrosis (100-150 Mg of L-thyroxine per 1 kg of body mass daily for 10-12 days) was determined by liquid chromatography with a high resolution. A decrease in the content of deoxyguanosine, thymine, hypoxanthine, cytosine, thymidine and an increase in the content of inosine, adenine and adenosine in the liver of animals with hypothyrosis were shown. In the brain of these rabbits the level of cytidine was lowered, and the levels of deoxyguanosine, thymine, inosine, hypoxanthine, adenine and uracil were on an increase. An increase in the levels of deoxyguanosine, thymine, adenine, thymidine and a decrease in the levels of cytidine, hypoxanthine, cytosine, adenine and uracil in the liver were noted in hyperthyrosis. In the brain of rabbits with hyperthyrosis an increase in the levels of deoxyguanosine, cytidine, inosine and adenine was combined with a decrease in the levels of thymine and hypoxanthine. These thyroid-dependent changes in the content of registered metabolites and precursors of nucleic acids in tissues suggest that the observed shifts illustrate one of many mechanisms of the regulation of cell metabolism by thyroid hormones.