Relationship between in Vivo Insulin Resistance and Decreased Insulin Receptors in Obese Man*

Abstract

ABSTRACT We have studied the relationship between in vivo insulin sensitivity and in vitro insulin binding to adipocytes in obese and nonobese subjects. Insulin binding studies demonstrated a 40% (P > 0.01) decrease in the number of receptor sites per cell in adipocytes from the obese patients. Insulin sensitivity was assessed by a previously defined technique in which insulin and glucose are constantly administered while endogenous insulin secretion is inhibited by an infusion of epinephrine (6 μg/min) and propranolol (0.08 mg/min). Using this technique, the resulting steady state plasma glucose (SSPG) levels provide a measure of overall in vivo insulin sensitivity. The dose-response relationship between the steady state plasma insulin concentration and glucose disposal was determined by performing three separate infusions on each subject in which the glucose infusion rate was kept constant while the rate of insulin infusion was serially increased in each study. Compared to the normal subjects, the dose-...