Changes in serum ghrelin concentration following biliopancreatic diversion for obesity.

OBJECTIVE: Ghrelin is a recently discovered hormone that is produced mainly by the stomach and that increases food intake in rodents and humans. It has been postulated that the weight loss after gastric bypass surgery for obesity might be related to changes in serum ghrelin concentration. RESEARCH METHODS AND PROCEDURES: Serum leptin and ghrelin concentrations were measured in a group of obese patients before biliopancreatic diversion (BPD) and 2 and 12 months postoperatively. Insulin sensitivity was determined from serum glucose and insulin levels according to the homeostatic model of assessment for insulin resistance (HOMA IR). RESULTS: A sharp drop was observed in body weight, in BMI values, in HOMA IR data, and in serum leptin concentration at 2 and 12 months after BPD, whereas a significant increase of serum ghrelin level was observed at 12 months, when food intake had returned to preoperative levels. A negative correlation between the postoperative changes of serum ghrelin concentration and those of HOMA IR values was observed at 2 and 12 months after BPD. DISCUSSION: No evidence upholding a relationship between serum ghrelin concentration and food intake after BPD was seen; the postoperative changes likely reflected the achievement of a new state of energy balance. The negative relationship observed between post-BPD changes in HOMA IR values and changes in serum ghrelin concentration supported the role of insulin in the modulation of ghrelin production.