[Formation of microliths in the kidneys of rats on a diet with high RNA content]

When 25% RNA to the protein mass was introduced in the ration given to rats, deposition of urates occurred in the kidneys of the animals in the form of microlites of different sizes. These microlites were found in lumina of distal parts of the convoluted tubules and collective tubules at 21 days of the experiment. In addition to RNA, microlites included RNA, neutral and acid mucopolysaccharides, as well as calcium salts. The epithelium of the tubules at sites of microlite localization underwent necrobiotic changes, sometimes it was desquamated, and the walls of the tubules were represented only by a markedly thickened basal membrane. As a rule, no interstitial tissue reaction was observed at sites of microlites localization.