[Polyamine concentrations in the liver and kidney tissues of rats of different ages]

The spermidine and spermine contents in the liver and kidney tissues were determined for rats of different age. The age peculiarities in the polyamine content are revealed in the rat liver and are not observed in the kidneys. Spermidine prevails in the young rat liver, but spermine in the adult rat liver. The spermidine content in the young rat liver calculating per 1 g of fresh weight or per 1 mg of RNA is on the average twice as high as in adult animals. Spermine prevails in kidneys of both the growing and adult animals. The age peculiarities of the polyamine content in the liver are supposed to be connected with its protein-synthetizing function: the spermidine high content may be due to rapid synthesis of extracellular proteins which are necessary to the growing organism.