The Insulin Receptor

Studies with bulky and insoluble insulin derivatives indicate that this hormone can activate various metabolic processes by interaction with cell surface structures. A definition of “receptor” is offered which is operationally useful in studies directed to the identification and purification of receptor structures. Studies are described which measure the specific binding of insulin to intact fat cells and liver and fat cell membranes. The properties of these interactions and the correlation with metabolic events indicate that biologically significant receptors are being studied. The possible contribution of membrane carbohydrates, proteins and lipids to the environment and function of the receptor is considered. Studies pertinent to the extraction and purification of the insulin receptor are discussed.