[The effect of insulin on the metabolism of isolated rat glomeruli (author's transl)].

Glomeruli isolated from the kidneys of metabolically normal and diabetic rats were investigated morphologically and metabolically. Glomeruli from chronically diabetic animals showed significantly increased contents of DNA and protein, and an altered DNA/protein ratio. These changes were prevented by insulin treatment in vivo of diabetic rats. Insulin had no effect on glucose degradation by the glomeruli of normal or diabetic rats. Protein synthesis is unchanged in the glomeruli from acutely diabetic rats, but shows a significant increase in those from chronically diabetic animals. In the glomeruli of normal animals, both protein synthesis and RNA synthesis are increased in vitro by insulin, but this effect is absent from the glomeruli of diabetic rats. Under in vitro conditions there is a resistance to insulin. Changes in protein and RNA synthesis can be prevented by insulin only when it is administered in vivo. In addition, the incorporation of lysine and uridine in the glomeruli of normal animals was dependent on the glucose concentration. It is concluded from these results that insulin deficiency and increased blood sugar level are accompanied by characteristic changes in the metabolism of protein and RNA, which are related to morphologically and biochemically detectable structural changes.