Endocrine Abstracts

Background: Leptin and both forms of ghrelin (acylated and des-acylated) are peptide hormones involved in appetite control and food intake regulation in humans. It has been thought that circulating ghrelin concentrations are elevated by fasting and suppressed following a meal, whereas leptin concentrations change in the opposite direction. Most studies, however, only examined these changes after a standardized meal and at different points in time.

Objective: The aim of the present study was to investigate whether plasma concentrations of leptin, acylated and des-acylated ghrelin measured in healthy individuals are different before and short term after an unstandardized meal.

Method: Twenty healthy individuals, aged 24 to 54, equally divided by sex (body mass index in kg/m² 18.1-37.7), participated in the study. Blood samples were obtained twice: after an overnight fast and 2 hours after a meal with different macronutrient composition, in order to assess plasma concentrations of leptin, acylated and des-acylated ghrelin using ELISA kits.

Results: Plasma concentrations of leptin and des-acylated ghrelin were higher in females compared to male subjects. Leptin concentrations were also higher in overweight/obese than in normal weight individuals. No difference has been found between fasting and postprandial concentrations of leptin, acylated and des-acylated ghrelin, nor acylated to des-acylated ghrelin ratio.

Conclusions: No significant short-term changes were observed in plasma concentrations of appetite hormones before and after the meal. It seems that the regulation of postprandial satiety is only partially dependent on ghrelin and leptin response. Moreover, these data suggest, that the meal composition (e.g. high proportion of carbohydrates) may affect leptin and ghrelin plasma concentrations to the greater degree than just food ingestion.