Stimulation of 3H-uridine incorporation into ribosomal ribonucleic acids by insulin

Ribosomal RNA was extracted from hepatic ribosomal subunits of rats treated with alloxan or with alloxan and insulin and additionally injected with 3H-uridine. Sedimentation of the extracted RNA through sucrose, gradients with registration of the optical density and with measurement of the radioactivity of rRNA reveals reduction of uridine incorporation after the induction of diabetes of diabetes mellitus. If alloxan-diabetic animals are substituted with insulin, this decrease in uridine incorporation is reversed to incorporation rates which even exceed uridine incorporation of control animals. With regard to the reduction of protein synthesis in diabetes mellitus this finding of reduced rRNA synthesis is suggested to be an additional factor in the reduction of ribosomal aggregation.