Leptin inhibits feeding, stimulates thermogenesis and decreases body weight. Serotonin
reduces food intake when injected into the hypothalamus and may interact with other
neurotransmitters in the control of appetite. We therefore investigated the effects
of the serotonergic drug fluoxetine, which inhibits serotonin reuptake, on food intake
and plasma leptin levels in lean and obese Zucker rats. Fluoxetine significantly reduced
food intake in lean and obese rats, both acutely after a single injection (10 mg/kg)
and during continuous subcutaneous infusion (10 mg/kg/day for 7 days). Plasma leptin
levels were reduced after both 4 hours and 7 days of fluoxetine administration in
lean and after 7 days in fatty rats (all p < 0.01). We have previously suggested that
serotonin may decrease food intake by inhibiting neuropeptide Y neurones, and we further
suggest that it also inhibits leptin, possibly by an effect on white adipose tissue.
Key words
Hypothalamus - Leptin - Obesity - Zucker
