Prolonged malnutrition in individuals with anorexia nervosa (AN) has been associated with alterations in endocrine function that may play a sustaining role in the disorder. We hypothesized that abnormalities in endocrine responses to ingestion of a meal in AN are reversible and depend on weight restoration. We measured meal-induced endocrine responses in AN subjects at three time points during hospitalization: before refeeding (n = 13, mean BMI 16.7 kg/m(2)), after 2 wk of refeeding (mean BMI 18.0 kg/m(2)), and in the weight-restored state (mean BMI 20.3 kg/m(2)). Control subjects (n = 13, BMI 19-24.9 kg/m(2)) were tested once. Tests were 2.5-h sessions in which blood was drawn every 15 min before, during, and after a approximately 650-kcal test breakfast. Relative to controls, peak levels of glucose were depressed and peak levels of insulin in response to ingestion of the test meal were delayed, with response patterns in the third trial most similar to controls. Pancreatic polypeptide (PP) levels were increased in AN relative to controls regardless of weight status. The delay in insulin release and elevated PP levels did not correct with short-term refeeding and may contribute to the high relapse rates and maintenance of AN.