Effect of chronic fluoxetine treatment on male and female rat erythrocyte and prefrontal cortex fatty acid composition

►Chronic fluoxetine treatment resulted in clinically-relevant plasma fluoxetine concentrations in male and female rats, and significantly decreased serotonin turnover in the prefrontal cortex. ►Chronic fluoxetine treatment did not significantly alter erythrocyte fatty acid composition in male or female rats.►Chronic fluoxetine treatment significantly and selectively increased docosapentaenoic acid (22:5n-6) in the prefrontal cortex of female rats, but not in male rats.► These results do not support the hypothesis that chronic fluoxetine treatment increases omega-3 fatty acid biosynthesis or membrane composition.