Role of Growth Hormone Antagonism in Modulating Insulin Sensitivity in Subjects With Insulin Resistance But Without Diabetes

Growth hormone is well known to cause changes in glucose regulation. People with Laron syndrome are born without the growth hormone receptor and are protected from diabetes. Mice who are engineered without the growth hormone receptor are similarly protected from diabetes. Conversely, people who have excessive amounts of growth hormone, such as patients with acromegaly, have an increased risk for type 2 diabetes. In acromegaly patients, treatment with pegvisomant, a medication that reduces insulin like growth factor-1 by blocking the growth hormone receptor, significantly improves insulin resistance. Pegvisomant has not been explored as a possibility for the treatment of type 2 diabetes or insulin resistance in people without acromegaly. In this study, the investigators hope to study the metabolic effects of pegvisomant on people who have insulin resistance but not diabetes. Pegivosmant is expected to improve insulin resistance in the liver, fat and muscle as well as decrease serum free fatty acids.