Central-peripheral communication systems integrate all the mechanisms that allow the dialogue between the brain and peripheral organs for the control of energy homeostasis. The impairment of this system leads to the development of metabolic disorders such as liver and cardiovascular disease, obesity and diabetes. Peripheral hormones secreted by metabolic tissues, by binding to their receptors in the brain, will inform about the whole-body metabolic status, modulating feeding behaviour, energy expenditure and glucose metabolism. However, the mechanisms that control the access of these blood-borne hormones and nutrients to the ARH neurons to modulate energy homeostasis, were poorly characterized until now.

In the hypothalamus, the trafficking of molecules between the peripheral circulation and the central nervous system is restricted by regulated interfaces, the blood-brain barrier (BBB) and the circumventricular organs (CVO). The median eminence (ME) is a CVO formed by fenestrated microvessels and specialised ependymoglial cells named tanycytes, that form the floor of the third ventricle. Tanycytes, by gating the passage of blood-borne hormones such as leptin and insulin into the hypothalamus and by sensing peripheral glucose, can modulate energy homeostasis.

Thus, thanks to the capacity of tanycytes to modulate ME-barrier and to transport blood-borne molecules, I will present how tanycytes are implicated in the efficiency of GLP1R-agonists over exert their anti-obesity and anti-diabetic actions.