GHRL and Alzheimer disease: The present study was aimed at investigating the relationship between ghrelin and leptin in alcohol craving by analyzing these serum levels in a human laboratory placebo-controlled study with heavy-drinking AD individuals receiving intravenous ghrelin.10 Consistent with the opposite physiological roles of ghrelin vs leptin,19, 20 our hypothesis was that intravenous exogenous ghrelin administration acutely decreases endogenous serum leptin levels, and that changes in leptin levels negatively correlate with alcohol craving.