[Concentration of free nucleotides and turnover of adenine nucleotides in the liver of birds of different ages].

The content of free nucleotides and exchangeability of adenine nucleotides were studied in the liver of 1- and 18-month cocks. It is established that adenine nucleotides in the young cocks liver account for 40%, uridine nucleotides for 29%, cytidine nucleotides for 13% of the total amount of nucleotides. These ratios are maintained with age but the amount of adenine nucleotides decreases by 35% and that of uridine nucleotides by 22%. Against a background of a relatively constant level of adenine and uridine nucleotides the content of cytidine and guanine nucleotides varies synchronously within wide ranges, which can evidence for the presence of a common mechanism of regulating synthesis of these metabolites. A direct correlation is detected between the amount of adenine nucleotides and their specific radioactivity. This is due to a higher intensity of synthetic processes in young cocks. The inverse correlation is observed in adult cocks, that results from the effect of "label dilution".