Aim: Leptin is likely to be involved in the homeostasis of body weight. This study aimed to examine the acute effects of orlistat on postprandial serum glucose, insulin, and leptin levels before any effect on body weight occurred.
Methods: Thirty-four nondiabetic, obese patients were enrolled in this study (body mass index, 35.7+/-3.8 kg/m(2)). Patients were randomly assigned to two groups, one receiving orlistat (120 mg, single dose), and the other received a placebo. A single dose was given before a standard 600-kcal mixed meal containing 60% carbohydrates, 25% lipids, and 15% protein. Blood samples were collected basally before the test meal and then hourly for five hours. Graphic tendencies, peak values, time needed to reach the peak values, and area under the curve values were compared between groups.
Results: There were no differences in sex distribution, mean age, anthropometric measurements, and basal glucose, insulin, and leptin levels between the orlistat and placebo groups. Hourly serum glucose and insulin changes were similar between groups, peak levels of insulin occurred in the first hour in control group, although peak levels of insulin did not occur until the second hour in patients in the orlistat group. Also, serum leptin levels had a more horizontal and delayed increase after a mixed meal in patients in the orlistat group than they did in patients in the placebo group. There were no statistically significant differences between the groups.
Conclusion: One dose of 120 mg orlistat made no changes in postprandial serum glucose, insulin, and leptin levels, although leptin-level increases were smaller in patients receiving orlistat.