Ghrelin is Supressed by Intravenous Alcohol and is Related to Stimulant and Sedative Effects of Alcohol

Evidence indicates that feeding-related peptides, such as ghrelin, have a role in the rewarding properties of addictive substances like alcohol. Oral alcohol administration significantly suppresses ghrelin. This study was designed to evaluate the effects of two doses of alcohol on ghrelin and examine if ghrelin levels predict the subjective effects of alcohol. Healthy social drinkers (N = 20) participated in three, randomly assigned, and counterbalanced laboratory sessions. During each session they received a continuous IV infusion of either placebo (saline), low dose (40 mg%) or high dose (100 mg%) of alcohol. Participants were given a standardized, light breakfast 90 min before the start of the infusion. Ghrelin levels [acyl ghrelin (AG) and total ghrelin (TG)] were collected at four time points before, during and after the infusion. Subjective effects of alcohol, using the BAES, were evaluated before, during and after alcohol infusion. IV alcohol significantly reduced AG but not TG levels with no difference between the two doses of alcohol. The percent change (%∆) in AG suppression was substantial in both high dose (43.4%∆), and low dose (39.5%∆) of alcohol. Also, fasting AG and TG levels were significant predictors of alcohol stimulant and sedative effects. Higher fasting ghrelin levels were associated with longer and more intense subjective effects. The results provide evidence that IV alcohol suppresses ghrelin levels similarly to oral alcohol. This study is the first to show that ghrelin predicts subjective effects of alcohol, suggesting that ghrelin may have a role in the rewarding mechanisms for alcohol. Intravenous alcohol infusion (low dose and high dose of alcohol) when compared to placebo (saline) significantly suppresses ghrelin in healthy social drinkers. Fasting ghrelin levels also predict subjective behavioral effects of alcohol. Those with higher fasting ghrelin levels tend to experience alcohol effects longer and more intensely.