Gastric bypass has been reported to be associated with markedly suppressed plasma ghrelin levels, suggesting that it is one of the possible weight-reducing factors related to this procedure. The aim of this study was the evaluation of plasma ghrelin levels in patients who had undergone laparoscopic Roux-en-Y gastric bypass (LRYGBP) and laparoscopic adjustable silicone gastric banding (LASGB). Normoweight, obese subjects and patients who had undergone total gastrectomy were used as controls. In this cross-sectional study, we selected 10 subjects who underwent LASGB, 11 subjects with LRYGBP, 10 obese subjects, eight patients with total gastrectomy, and eight normoweight subjects. Plasma ghrelin, insulin, and glucose profiles were determined before and after breakfast and lunch. Obese subjects showed a ghrelin plasma level significantly lower than normoweight subjects (407.3 +/- 21.6 vs. 813 +/- 72.4 pg/ml, P < 0.01). Patients with LRYGBP showed baseline ghrelin levels lower than LASGB (213.5 +/- 73.9 vs. 314.2 +/- 84.3 pg/ml, P = 0.04). Both groups of patients who underwent bariatric surgical procedures also had ghrelin lower than normoweight and obese subjects (P < 0.01 and P < 0.05, respectively). Patients with total gastrectomy showed plasmatic ghrelin levels extremely lower than those in all other groups (32.6 +/- 18.7 pg/ml, P < 0.001 for all). The ghrelin profile in both groups of subjects who underwent LRYGBP and LASGB did not show any meal-related changes as observed in obese and normoweight control groups. Significant difference in plasma ghrelin levels between LRYGBP and LASGB was found, suggesting that both procedures could induce weight loss by different mechanisms in which ghrelin could be involved.