OR19-3 Intranasal Oxytocin Reduces the Expression of Impulsive Behavior in Overweight and Obese Men

Program: Abstracts - Orals, Poster Previews, and Posters
Session: OR19-Regulation of Energy Balance
Bench to Bedside
Saturday, April 2, 2016: 11:45 AM-1:15 PM
Presentation Start Time: 12:15 PM
Room 205 (BCEC)
Franziska Plessow*, Dean A. Marengi Jr., Sylvia K. Perry and Elizabeth A. Lawson
Massachusetts General Hospital/Harvard Medical School, Boston, MA
Recent research suggests that the hypothalamic neuropeptide oxytocin (OXT) acts as a critical central nervous system factor in mediating food intake and weight. In a randomized, double-blind, placebo-controlled crossover study in 25 healthy normal-weight and obese men, we have previously shown that a single dose of 24 IU intranasal OXT reduces total caloric and fat intake at a meal 60 min after administration. However, the underlying mechanisms are yet to be uncovered. Since OXT administration has been shown to affect motivational aspects of higher-order cognitive processes and decision-making in social contexts, we hypothesized that OXT reduces food intake in part by decreasing the expression of impulsive behavior. We performed a double-blind, placebo-controlled crossover pilot study with 24 IU intranasal OXT in 10 healthy overweight/obese men. Fifteen minutes after receiving OXT or placebo, participants completed a stop-signal paradigm, a widely used task to assess strategy and ability to suppress behavioral impulses. In this paradigm, participants categorize stimuli by pressing response keys but are instructed to withhold their response when a stop signal appears. Response execution (go process) and its inhibition (stop process) compete with each other. If the go process wins, a response is provided. If the stop process finishes first, no response occurs. The likelihood of responding when a stop signal appears (stop error) can be reduced by proactively decreasing speed in the go task. Participants were 23-43 years old (mean age±SEM: 31.5±1.8 years) with a body mass index (BMI) ranging from 25.7 to 33.9 kg/m2 (mean BMI±SEM: 28.7±0.7 kg/m2). After receiving OXT, subjects showed increased reaction times (RTs) in the go task compared to the placebo condition (936±83 vs. 833±88 ms, p=0.012). Similarly, they displayed fewer stop errors under OXT compared to placebo (36.4±2.4 vs. 41.2±2.8%, p=0.049). These results indicate that after a single dose of OXT, subjects proactively exert control over their behavior, increasing RT in the go task, which, in turn, reduces impulsiveness. This increased proactive control among the participants who received OXT represents a potential mechanism for the reported reduced food intake under OXT. The stop-signal RT did not differ across conditions (p=0.724), indicating that OXT does not alter the ability to suppress response impulses but solely reduces impulsive behavior by triggering a more cautious behavioral strategy. Since subjects do not reliably differentiate between OXT and placebo, we assume that the observed behavioral changes occurred without deliberation, e.g., via interoceptive signaling. Future studies are required to further characterize the increased control of behavior triggered by OXT administration, determine the underlying pathways, and establish the predictive value of the observed changes in behavioral control for food intake.

Nothing to Disclose: FP, DAM Jr., SKP, EAL

*Please take note of The Endocrine Society's News Embargo Policy at https://www.endocrine.org/news-room/endo-annual-meeting/pr-resources-for-endo

Sources of Research Support: Boston Nutrition Obesity Research Center/NIH Grant 5P30DK046200-20; Nutrition Obesity Research Center at Harvard/NIH Grant P30-DK040561