Insulin receptor binding and tyrosine kinase activity in liver and skeletal muscle from fasted rats

Insulin binding and tyrosine kinase activity of the insulin receptor have been measured in the liver and muscles of rats fed or submitted to a 72-h-fasting. In both tissues, insulin binding increased in fasting rats. In liver, the ability of insulin to simulate receptor tyrosine kinase activity greatly unpaired during fasting, but remained unchanged in muscle. The change during fasting of the insulin-stimulated tyrosine kinase activity of the insulin receptor is specific to certain tissue.