Differential effect of d-fenfluramine and metergoline on food intake in human subjects

This study investigated the effect of the 5-HT receptor blocker metergoline (MTG) on d-fenfluramine (d-FF)-induced reduction of food intake in 13 normal male human volunteer subjects. Food was freely available for 2h, 4h after drug administration, from a four-channel automated food dispenser. d-FF (30 mg) reduced total food intake and exerted a marked effect on non-sweet food which was attenuated by the addition of MTG (4 mg). d-FF had less effect on sweet-tasting food while intake of sweet food was significantly increased by MTG. There was a significant interaction between d-FF and MTG on sweet-tasting foods. No effect on MTG was observed on d-FF-induced changes in ratings of hunger.