Acipimox during exercise points to an inhibitory feedback of GH on ghrelin secretion in bulimic and healthy women.

Ghrelin is predominantly produced by the stomach and the growth hormone (GH)-ghrelin feedback loop between the stomach and the pituitary gland has recently been suggested. The disruption of the gut-brain axis might be involved in bulimia nervosa (BN). We investigated responses of plasma GH, ghrelin, and neuropeptide Y (NPY) concentrations to exercise or to exercise after the administration of the antilipolytic drug Acipimox (Aci) in seven BN patients and seven healthy women (C). Aci was administered 1h before exercise (45 min, 2 W/kg of lean body mass/LBM/). Ghrelin, GH, NPY, free fatty acids (FFA) and glycerol plasma levels were measured during the test using commercial kits. The exercise induced an increase in plasma GH, NPY and FFA in both groups and a decrease in plasma ghrelin levels only in BN patients. Exercise after Aci administration resulted in an increase in plasma GH, and a decrease in plasma ghrelin in both groups; NPY increased more in BN patients. Exercise-induced FFA increase was depressed after Aci. We conclude that the Aci-induced suppression in plasma ghrelin levels during exercise in both groups suggests a negative feedback of GH on ghrelin secretion. Observed changes in plasma FFA levels were not related to changes in GH and ghrelin levels.