Repeated hypothalamic stimulation with neuropeptide Y increases daily carbohydrate and fat intake and body weight gain in female rats.
Neuropeptide Y (NPY), repeatedly injected in the hypothalamic paraventricular nucleus (PVN), produces dramatic obesity and overeating in female rats maintained on a single nutritionally complete diet. In the present study, we investigated whether these effects could also be obtained in animals with a choice of three pure macronutrients: protein, carbohydrate, and fat. Female rats with indwelling PVN cannulas were injected with NPY (235 pmol) or its saline vehicle every 8 hr for 6 days. A third group was left undisturbed. Consumption of each macronutrient and body weight were measured every 24 hr for 6 days preinjection, 6 days during injections, and 21 days after the injections were terminated. Relative to vehicle or preinjection rates of body weight gain (approximately 1.5 g/day), NPY dramatically enhanced weight gain to a rate of 9.3 g/day and more than doubled total daily food intake. This augmentation was accounted for by increases in carbohydrate intake (+26.4 kcal/day) and fat intake (+48.5 kcal/day), with no significant potentiation of protein consumption. When the NPY injections were terminated, body weight and macronutrient intake returned to control levels within 1 or 2 weeks. These findings are consistent with a role for NPY in hypothalamic mechanisms of macronutrient intake and body weight regulation and suggest that disturbances in brain NPY may contribute to the development of eating and weight disorders.
Stanley
B G
BG
Rockefeller University, New York, NY 10021.
Anderson
K C
KC
Grayson
M H
MH
Leibowitz
S F
SF
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D005247:Feeding Behavior / Q000187:drug effects*; D005260:Female; D005518:Food Preferences / Q000187:drug effects; D007031:Hypothalamus / Q000502:physiology*; D007276:Injections, Intraventricular; D009478:Neuropeptide Y / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D015430:Weight Gain / Q000187:drug effects*
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D009478:Neuropeptide Y