Obesity impairs arcuate (ARC) NPY/AgRP neuronal function and renders these homeostatic neurons unresponsive to the orexigenic hormone ghrelin. In the current study, we investigated the effect of diet-induced obesity (DIO) on feeding behaviour, ARC neuronal activation and mRNA expression following another orexigenic stimulus, an overnight fast. We show that 9 weeks of high-fat feeding attenuates fasting-induced hyperphagia by suppressing ARC neuronal activation and hypothalamic NPY/AgRP mRNA expression. Thus, the lack of appropriate feeding responses in DIO mice to a fast is caused by failure ARC neurons to recognize and/or respond to orexigenic cues. We propose that fasting-induced hyperphagia is regulated not by homeostatic control of appetite in DIO mice, but rather due to changes in the reward circuitry.
Briggs, D., Lemus, M., Kua, E., & Andrews, Z. (2011). Diet-induced obesity attenuates fasting-induced hyperphagia. Journal of Neuroendocrinology, 23(7), 620 - 626. https://doi.org/10.1111/j.1365-2826.2011.02148.x