Plasma acyl-ghrelin increases after meal initiation: a new insight

Plasma ghrelin secretion over time in humans is characterized by pre-prandial increases and by post-prandial decreases all day long. However, some authors who measured ghrelin concentrations around meals showed a rise in plasma ghrelin concentration after meal initiation followed by the typical post-prandial decrease. In order to confirm this observation that has never been discussed, we described ghrelin profiles around four eating episodes in the morning in adult men.

Twenty normal-weight and 17 obese men were instructed to eat four fixed meals (706 kJ) 10 min long at 0800 h, 0900 h, 1000 h and 1100 h. Using frequent blood sampling, we determined plasma acyl-ghrelin concentrations around those eating episodes. Glucose, insulin and GLP-1 concentrations were also measured.

The meals consumption induced a significant increase in plasma acyl-ghrelin concentrations 10 min after meal initiation (P<0.0001): +20.9±5.8 and +10.7±3.3 pg/ml in normal-weight and obese subjects for the first meal; +10.4±3.0 and +5.5±3.9 pg/ml in normal-weight and obese subjects for the second meal; +12.4±3.6 and +4.2±2.1 pg/ml in normal-weight and obese subjects for the third meal; and +4.4±4.1 and +3.3±2.61 pg/ml in normal-weight and obese subjects for the fourth meal.

This study is the first to describe and discuss the post-meal initiation ghrelin increase. This finding is consistent in normal-weight and obese individuals.