番茄社区

NEW ORLEANS -- The hormone oxytocin holds promise as a therapy for overweight/obese men, researchers reported here.

In a small, placebo-controlled crossover study of overweight/obese men, intranasal oxytocin significantly attenuated connectivity between the ventral tegmental area (VTA) and certain areas of the brain responsible for food motivation, according to Liya Kerem, MD, of Massachusetts General Hospital in Boston, and colleagues.

After administering 24 IU of intranasal oxytocin, there was a significant reduction in activation of the insula, somatosensory cortex, operculum, temporal gyrus, as well as the amygdala and hippocampus after viewing high-calorie foods, Kerem said in a presentation at ENDO 2019, The Endocrine Society annual meeting.

"Since we know that overconsumption of high-calorie foods is a major contributor of obesity, targeting the hyperactivation of reward areas with oxytocin may inhibit overeating behavior," Kerem stated during an ENDO 2019 press conference.

The 10-man randomized study used functional MRIs to look at activation of the brain in response to viewing 100 visual prompts of high-calorie foods like doughnuts, healthy foods; non-food items such as tools; and ambiguous fixation images. Besides overweight/obesity, these participants were otherwise healthy, non-diabetic men with an average BMI of 29.

In these overweight/obese men, imaging showed a hyperactivation of the brain areas connected to the VTA -- the basis and "seed region" of the mesolimbic dopamine reward system -- only after looking at these high-calorie foods.

After an overnight fast, participants were given one intranasal dose of oxytocin and then underwent a function MRI 1 hour later. No adverse events or side effects were reported after this single dose of oxytocin.

"This study provides novel insights into the neural circuits regulated by acute intranasal oxytocin administration," Emily Gallagher, MD, of the Icahn School of Medicine at Mount Sinai in New York City, told 番茄社区.

Gallagher, who was not involved in the study, noted that the "long-term consequences of oxytocin administration need to be carefully investigated. Additionally, in its current form, intranasal oxytocin has a short half-life, making it inconvenient for long-term use."

"Expanding our knowledge of the mechanisms of oxytocin action by studies such as Dr. Kerem's will allow for the potential development of therapeutic strategies to target these neural networks in the treatment of obesity," she added.

Kerem told 番茄社区 that her group is currently "doing a big NIH-funded study in which 60 [participants] are involved, given oxytocin daily before every meal and at bedtime for 8 weeks."

"There is only one study in which oxytocin was before, and it was a pilot study with goods results with weight loss. The rest of the studies have looked at oxytocin administration just with a single dose, so we still need more information to understand what would be the effects of prolonged administration," she stated.

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