Reduction of fat and protein intakes but not carbohydrate intake followingacute and chronic fluoxetine in female rats

Fluoxetine hydrochloride, a selective serotonin reuptake inhibitor, leads t o reductions in food intake and body weight and is under investigation as a possible treatment for obesity. Additionally, it has been suggested that f luoxetine administration could lead to a selective suppression in carbohydr ate consumption. Because women more often than men seek weight reduction tr eatment, the present study examined the acute and chronic effects of fluoxe tine on food intake, macronutrient selection, body weight, estrous cycle, a nd motor activity in female rats. Female Long-Evans rats were provided with separate sources of protein, fat and carbohydrate, and nutrient intakes we re recorded following single (5.0, 10.0, and 20.0 mg/kg, IP) and chronic da ily (10 mg/kg for 28 days) injections of fluoxetine. Acute and chronic admi nistration of fluoxetine significantly reduced total caloric intake when co mpared to vehicle treatment. Moreover, fluoxetine significantly suppressed fat and protein intakes, but not carbohydrate intake following both acute a nd chronic drug administration. Animals chronically treated with fluoxetine gained significantly less weight than animals treated with vehicle. Chroni c fluoxetine treatment did not significantly alter estrous cycle. However, in both fluoxetine- and vehicle-treated animals, total caloric intake, and carbohydrate and protein intakes were reduced and fat intake was increased when estrogen levels were high. Fluoxetine significantly reduced motor acti vity up to 4 h postinjection, and increased motor activity 24 h postinjecti on. (C) 1999 Elsevier Science Inc.