title: Oxytocin reduces caloric intake in men.
abstract: OBJECTIVE
  Preclinical studies indicate that oxytocin is anorexigenic and has beneficial metabolic effects. Oxytocin effects on nutrition and metabolism in humans are not well defined. It was hypothesized that oxytocin would reduce caloric intake and appetite and alter levels of appetite-regulating hormones. Metabolic effects of oxytocin were also explored.
  
  
  METHODS
  A randomized, placebo-controlled crossover study of single-dose intranasal oxytocin (24 IU) in 25 fasting healthy men was performed. After oxytocin/placebo, subjects selected breakfast from a menu and were given double portions. Caloric content of food consumed was measured. Visual analog scales were used to assess appetite, and blood was drawn for appetite-regulating hormones, insulin, and glucose before and after oxytocin/placebo. Indirect calorimetry assessed resting energy expenditure (REE) and substrate utilization.
  
  
  RESULTS
  Oxytocin reduced caloric intake with a preferential effect on fat intake and increased levels of the anorexigenic hormone cholecystokinin without affecting appetite or other appetite-regulating hormones. There was no effect of oxytocin on REE. Oxytocin resulted in a shift from carbohydrate to fat utilization and improved insulin sensitivity.
  
  
  CONCLUSIONS
  Intranasal oxytocin reduces caloric intake and has beneficial metabolic effects in men without concerning side effects. The efficacy and safety of sustained oxytocin administration in the treatment of obesity warrants investigation.
authors: Neuroendocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA.
authors: Elizabeth A
authors: EA
authors: Lawson
authors: Dean A
authors: DA
authors: Marengi
authors: Rebecca L
authors: RL
authors: DeSanti
authors: Tara M
authors: TM
authors: Holmes
authors: David A
authors: DA
authors: Schoenfeld
authors: Christiane J
authors: CJ
authors: Tolley
mesh_terms: D000281:Administration, Intranasal; D000293:Adolescent; D000328:Adult; D001066:Appetite / Q000187:drug effects*; D001067:Appetite Depressants / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D001786:Blood Glucose / Q000378:metabolism; D002153:Calorimetry, Indirect; D002766:Cholecystokinin / Q000097:blood; D018592:Cross-Over Studies; D002149:Energy Intake / Q000187:drug effects*; D004734:Energy Metabolism / Q000187:drug effects*; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D010121:Oxytocin / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D001067:Appetite Depressants; D001786:Blood Glucose; D007328:Insulin; D010121:Oxytocin; D002766:Cholecystokinin