title: Intraperitoneal leptin modifies macronutrient choice in self-selecting rats.
abstract: This study aimed to evaluate the consequences on food intake and body weight (BW) of leptin administration in rats receiving a choice between the three macronutrients. Two studies were performed: during the first, rats received an acute intraperitoneal (IP) leptin administration (1 mg/kg) twice (at 8 and 14 weeks of age), at the beginning of the nocturnal cycle, while during the second, they received a chronic leptin infusion (osmotic minipump, 7 days). The total 24-h food intake after acute leptin injections was reduced by 14% and 17%, respectively. Body weight gain (BWG) after leptin injections was about half that seen on control days. Chronic leptin infusion reduced total intake, affecting mainly protein (P). Fat intake increased slightly since day 2 and became significant on the fourth day. After the leptin infusion, carbohydrate (CHO) eaters (>35% carbohydrate/total energy) significantly reduced the carbohydrate proportion in their total energy intake. There was no difference concerning macronutrient selection by fat eaters (Hfat). Leptin infusion reduced the number of mixed meals on the first day. In addition, the thermogenesis of brown adipose tissue (BAT) was higher in leptin than in control (C) rats. Consequently, leptin injections reduced food intake and BWG and increased thermogenesis, thus acting on the two terms of the energy balance. Moreover, leptin has different effects on macronutrient preferences, dependent upon age (tests 1 and 2) and the type (acute or chronic) of injection. High leptinemia level related to age or to minipump infusion lead to leptin resistance as found in old or obese subjects. It could explain our results.
authors.affiliation: UMR INRA/INAPG 914 Physiologie de la Nutrition et du Comportement Alimentaire Institut National Agronomique de Paris-Grignon, 16, rue Claude Bernard. 75231 Paris Cedex 05, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Wetzler
authors.forename: Valérie
authors.initials: V
authors.lastname: Dumaz
authors.forename: Marc
authors.initials: M
authors.lastname: Goubern
authors.forename: Daniel
authors.initials: D
authors.lastname: Tomé
authors.forename: Christiane
authors.initials: C
authors.lastname: Larue-Achagiotis
mesh_terms: D002001:Adipose Tissue, Brown / Q000187:drug effects; D000818:Animals; D001823:Body Composition / Q000187:drug effects; D004032:Diet; D004040:Dietary Carbohydrates; D004343:Drug Implants; D004734:Energy Metabolism / Q000187:drug effects; D005518:Food Preferences / Q000187:drug effects*; D006728:Hormones / Q000097:blood; D007274:Injections, Intraperitoneal; D020738:Leptin / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015430:Weight Gain / Q000187:drug effects
chemical_list: D004040:Dietary Carbohydrates; D004343:Drug Implants; D006728:Hormones; D020738:Leptin