Chronic d-fenfluramine treatment reduces fat intake independent of macronutrient preference.
We investigated the effect of chronic dexfenfluramine (DFEN) treatment on macronutrient selection in a three-choice diet paradigm using Sprague-Dawley rats. Baseline macronutrient intakes were measured for several days before the initiation of treatment. In Experiment 1, daily intraperitoneal injections of DFEN (1.5 mg/kg) or saline were administered 60 min before dark onset for 12 consecutive days and 24 h macronutrient intakes were measured. DFEN significantly reduced absolute fat intake (kcal) by 30% and relative fat intake (% of total energy) by 14% in animals that received dexfenfluramine treatment compared to controls over the 12-day period. Absolute carbohydrate intake was increased 24% compared to controls, but this difference was not significant. These changes in food intake resulted in a 10% lower total energy intake. Upon discontinuation of the drug, fat intake of the DFEN-treated rats rebounded to control levels within 24 h. In Experiment 2, rats were assigned to carbohydrate- or fat-preferring groups based on the ratio of their average daily carbohydrate to fat intake (kcal). All animals then received DFEN. During DFEN treatment, fat-preferring rats reduced their daily fat intake from 62 to 53% of total energy. The low baseline fat intake of carbohydrate-preferring rats was reduced even further by DFEN (from 24 to 15% of total energy). These corresponding effects of DFEN on macronutrient selection in both fat- and carbohydrate-preferring rats indicate that chronic DFEN treatment selectively suppressed fat intake independent of the preferred macronutrient diet.
Smith
B K
BK
Obesity, Diabetes and Metabolism Section, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge 70808-4124, USA.
York
D A
DA
Bray
G A
GA
D000818:Animals; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage; D004435:Eating / Q000187:drug effects* / Q000502:physiology; D005277:Fenfluramine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000502:physiology; D017366:Serotonin Receptor Agonists / Q000008:administration & dosage / Q000494:pharmacology*
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D017366:Serotonin Receptor Agonists; D005277:Fenfluramine; D012701:Serotonin