RESUMEN
CONTEXT: In healthy females, oxytocin levels decrease postmeal, corresponding to increased satiety. The postprandial response of oxytocin in females with anorexia nervosa (AN)/atypical AN is unknown. OBJECTIVES: To determine the pattern of postprandial serum oxytocin levels in females with AN/atypical AN, relationship with appetite, and effect of weight, eating behavior, and endogenous estrogen status. DESIGN: Cross-sectional. SETTING: Clinical research center. PARTICIPANTS: 67 women (36 with AN [<85% expected body weight (EBW)]; 31 with atypical AN [≥ 85% EBW)]), age 22.4 ± 0.9 (mean ± SEM) years, categorized by weight, restricting vs binge/purge behavior, and estrogen status. INTERVENTIONS: Standardized mixed meal. MAIN OUTCOME MEASUREMENTS: Blood sampling for oxytocin occurred fasting and 30, 60, and 120 minutes postmeal. Subjective appetite was assessed using visual analog scales. RESULTS: In females with AN/atypical AN, oxytocin levels decreased from fasting to 60 (P = 0.002) and 120 (P = 0.005) minutes postmeal. The decrease in oxytocin from fasting to 120 minutes was greater in females with atypical AN than AN (P = 0.027) and did not differ by restricting vs binge/purge behavior or estrogen status. Controlling for caloric intake, the decrease in oxytocin was inversely related to the decrease in hunger postmeal in females with atypical AN (P = 0.04). CONCLUSIONS: In females with AN/atypical AN, oxytocin levels decrease postmeal, as established in healthy females. Weight, but not restricting vs binge/purging nor endogenous estrogen status, affects postprandial oxytocin levels. The postprandial change in serum oxytocin levels is related to appetite in females with atypical AN only, suggesting a disconnect between oxytocin secretion and appetite in the undernourished state.
Asunto(s)
Anorexia Nerviosa/sangre , Regulación del Apetito/fisiología , Apetito/fisiología , Oxitocina/sangre , Adolescente , Adulto , Anorexia Nerviosa/fisiopatología , Niño , Estudios Transversales , Ayuno/sangre , Femenino , Humanos , Hambre/fisiología , Persona de Mediana Edad , Periodo Posprandial/fisiología , Saciedad/fisiología , Transducción de Señal/fisiología , Adulto JovenRESUMEN
CONTEXT: Oxytocin regulates a range of physiological processes including eating behavior and oxytocin administration reduces caloric intake in males. There are few data on oxytocin and eating behavior in healthy females or on the response of endogenous oxytocin to food intake and its relationship to appetite in humans. OBJECTIVES: To determine the postprandial pattern of oxytocin levels, the relationship between oxytocin and appetite, and the impact of menstrual cycle phase and age on oxytocin levels in females. DESIGN: Cross-sectional. SETTING: Clinical research center. PARTICIPANTS: Fifty-five healthy females (age 10 to 45 years). INTERVENTIONS: A standardized mixed meal was administered. MAIN OUTCOME MEASUREMENTS: Blood sampling for oxytocin occurred at fasting and at 30, 60, and 120 minutes postmeal. Appetite was assessed using Visual Analogue Scales pre- and postmeal. RESULTS: Mean fasting oxytocin levels were 1011.2 ± 52.3 pg/mL (SEM) and decreased at 30 and 60 minutes postmeal (P = 0.001 and P = 0.003, respectively). Mean oxytocin levels decreased19.6% ± 3.0% from baseline to nadir. Oxytocin area under the curve was lower in the early to midfollicular menstrual cycle phase (P = 0.0003) and higher in younger females (P = 0.002). The percent change in oxytocin (baseline to nadir) was associated with postprandial hunger (rs = -0.291, P = 0.03) and fullness (rs = 0.345, P = 0.009). These relations remained significant after controlling for calories consumed, menstrual cycle status, and age (P = 0.023 and P = 0.0001, respectively). CONCLUSIONS: Peripheral oxytocin levels in females decrease after a mixed meal and are associated with appetite independent of menstrual phase, age, and caloric intake, suggesting that endogenous oxytocin levels may play a role in perceived hunger and satiety.
Asunto(s)
Apetito/fisiología , Conducta Alimentaria/fisiología , Menstruación/psicología , Oxitocina/sangre , Adolescente , Adulto , Factores de Edad , Índice de Masa Corporal , Niño , Estudios Transversales , Femenino , Voluntarios Sanos , Humanos , Masculino , Menstruación/sangre , Persona de Mediana Edad , Oxitocina/fisiología , Periodo Posprandial , Adulto JovenRESUMEN
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.