Somatomedin Inhibitors in Serum and Liver of Growth Hormone-Deficient Diabetic Rats

Diabetes of moderate severity was induced with streptozotocin in growth hormone (and therefore somatomedin)-deficient rats. Somatomedin inhibitors were identified in the serum and liver perfusate of these animals, as shown by the ability of samples to blunt basal cartilage sulfation and cartilage stimulation by added normal serum. The data suggest that the induction of somatomedin inhibitors is under the influence of insulin and nutrition rather than growth hormone, indicating that their regulation may differ from that of growthpromoting somatomedins. With this model, it is possible to obtain preparations that are relatively free of somatomedins in which to study the properties of somatomedin inhibitors.