Acute insulin infusion decreases plasma ghrelin levels in uncomplicated obesity

Background: Plasma ghrelin levels have been shown to decrease after insulin infusion in lean subjects. Nevertheless, the mechanism of the suggested inhibitory effect of insulin on ghrelin is still unclear and no data about the effect of acute insulin infusion on plasma ghrelin concentration in obese subjects are available. Objective: We sight to evaluate plasma ghrelin concentration during an hyperinsulinemic euglycemic clamp in uncomplicated obese subjects. Methods: 35 uncomplicated obese subjects, body mass index (BMI) 43.3 +/- 10.1 kg/m(2), 33 women and 2 men, mean age 34.9 +/- 10, with a history of excess fat of at least 10 years underwent euglycemic hyperinsulinemic clamp. Blood samples for ghrelin were performed at baseline and steady state of euglycemic insulin clamp. Results: Ghrelin concentrations decreased over time to 10.6 +/- 15% (range 2-39%) of baseline, from a mean of 205.53 +/- 93.79 pg/ml to 179.03 +/- 70.43 pg/ml during the clamp (95% Cl, 10.69 to 36.44, P<0.01). In a univariate linear regression analysis baseline plasma ghrelin levels were inversely correlated to BMI (r = - 0.564, P = 0.04). A linear positive trend between whole body glucose utilization (M-FFMkg index) and ghrelin reduction during the clamp was found (chi(2) 3.05, p = 0.05). Conclusions: Our data seem to suggest that hyperinsulinemia during a euglycemic clamp is able to suppress plasma ghrelin concentrations in uncomplicated obesity. This effect appears to be positively related to insulin sensitivity. (C) 2004 Elsevier B.V. All rights reserved.