We have previously shown impaired neuroendocrine responses to ghrelin in patients with AN. The aim of this study was to investigate the metabolic responses during infusions of active ghrelin in severly malnourished patients with AN and compare them with responses of amenorrhoic AN patients who recovered body weight (PRAN) and constitutionally thin subjects (CTS) with regular menstrual cycles and without history of eating disorder and recent weight loss. Study was approved by the local ethics comitee and informed consent obtained from the patients.Twenty-five young women: 9 diagnosed with AN with very low body weight and BMI (12±0.4 kg/m2) 6 PRAN patients (17,2±1.3 kg/m2) and 10 CTS (17,6±0.4 kg/m2) were studied during 300 minute iv infusion of active ghrelin (dose 5 pmol/kg/min). Blood samples were obtained every 15 min. during first 2 hours and every 30 min. from that time point until the end of infusion for measurements of ghrelin, insulin, c-peptide and glycemia. At baseline, AN and PRAN patients had lower glycemia and higher insulin and c-peptide levels than CTS, but these differences were not statistically significant. Blood glucose levels significantly increased during ghrelin infusions in all three groups, but were significantly higher in CTS compared to PRAN and AN patients. In AN and PRAN patients insulin and c-peptide tended to decrease, but only changes in c-peptide levels in PRAN patients were statistically significant. In CTS, insulin and c-peptide levels significantly decreased and were significantly lower compared to AN and PRAN patients.
In conclusion, metabolic responses to ghrelin are impaired in patients with AN compared to constitutionally thin subjects and tend to improve with the gain of body weight.