Fluoxetine alters feeding behavior and leptin levels in chronically-stressed rats

Stress-induced alterations in feeding behavior are sexually dimorphic and have been related to changes in monoamine levels. Fluoxetine is commonly used as an antidepressant and has also been suggested as an adjunct to other strategies to treat obese individuals. Leptin may interact with stress hormones and with the brain serotonergic system, possibly affecting the feeding behavior of stressed rats. The aim of this study is to evaluate the interaction between chronic fluoxetine treatment and leptin levels in adult female Wistar rats submitted to chronic variable stress. After 30 days of stress, control and stressed groups were subdivided into two groups that received daily injections of vehicle or fluoxetine (8 mg/kg, i.p.). Body weight was evaluated before and after fluoxetine treatment. The animals gained weight with time, signifying that there is a difference in weight gain over time when fluoxetine-treated animals are, or not, subjected to the stress model. Both fluoxetine and stress induced a decrease in sweet food consumption. On the 60th day of fluoxetine treatment, leptin levels were decreased in fluoxetine-treated animals and there was no effect of stress. We conclude that chronic fluoxetine treatment induced a decreased intake of sweet food, as well as a reduction in leptin levels, and that this result could represent a compensatory response to reduced food intake rather than a direct anorectic mechanism. No interaction with chronic stress was observed.