Role of Reactive Oxygen Species in Signaling Feeding Behaviour

When produced transiently and moderately, reactive oxygen species (ROS) are not just by-products of substrate oxidation, they are also chemicals involved in intracellular signalling. The objective of this review is to explore the intracellular signaling aspects of reactive oxygen species in influencing feeding behaviour. Substrates such as glucose and lipids promote the generation of reactive oxygen species, primarily through mitochondria and, to a lesser extent, through NADPH oxidases. Under the influence of substrate level, the level of ROS generated in hypothalamic neurons such as NPY/AgRP and POMC neurons directly influences their activity and, as a result, affects downstream neurons located in other parts of the hypothalamus such as the ventromedial nucleus (VMN), the paraventricular nucleus (PVN), and the lateral hypothalamus. The activation of the POMC neuronal population is caused by an increase in ROS levels, whereas the activation of the NPY/AgRP neurons is caused by a decrease in ROS levels. The activation of these neurons determines feeding behaviour, which can be satiety if POMC neurons are activated or increased food intake if NPY/AgRP neurons are activated.