High‐fat diet (HFD) feeding induces elevations in ventromedial hypothalamus (VMH) norepinephrine and serotonin activity. Female Sprague‐Dawley (SD) rats (4 week old, n = 7‐9 per group) were fed either a HFD or rodent chow (RC) diet for 6 weeks and then 24‐h in vivo VMH extracellular profiles of monoamine metabolites were investigated by 24‐h microdialysis sampling in each group. Daily profiles of (A) NE, (B) MHPG and (C) 5‐HIAA in microdialysate samples from VMH of freely‐moving rats fed either HFD (●) or RC (○) (n = 7 or 8 per group). The horizontal bar indicates light and dark phases. HFD fed rats exhibited elevated levels of VMH 3‐methoxy‐4‐hydroxyphenylglycol (MHPG), norepinephrine (NE) and 5‐HIAA compared to RC diet rats (by 38%, 63% and 48%, respectively). Repeated measures anova on NE indicated a group effect (F
1,13 = 14.01, P < .005), as did repeated measures anova on MHPG (F
1,13 = 5.334, P < .05). Repeated measures anova on 5‐HIAA also revealed a group effect (F
1,13 = 7.630, P < .05)