THE HYPOTHALAMIC ACTION OF GHRELIN IS REQUIRED FOR A FULL RESPONSE OF THE HYPOTHALAMIC?PITUITARY?ADRENAL (HPA) AXIS TO FASTING

A.S CABRAL, G. FERNANDEZ, G. ZUBIRIA, M.J TOLOSA, L.HINTE, M. REYNALDO, G. GARCÍA ROMERO, A. GIOVAMBATTISTA, M. PERELLO

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedades de Biociencias

Ghrelin is a stomach-derived hormone that regulates food intake and severalneuroendocrine functions. Ghrelin acts via its specific receptor named growth hormone secretagogue receptor (GHSR), which is highly expressed in numerous brain nuclei regulating appetite such as the nucleus arcuate (ARC). As shown in the Figure, we have shown that the administration of ghrelin in ad-libitum fed mice actives the hypothalamic?pituitary?adrenal (HPA) axis and corticotropin-releasing factor (CRF) neurons of the hypothalamic paraventricular nucleus (PVN) via inhibition of the local γ-aminobutyric acid (GABA)ergic tone and independently of the ARC. Under fasting,ghrelin levels increase; however, the impact of endogenous increments of plasma ghrelin on the HPA axis is currently unknown.Here we studied the response of the HPA axis, at hypothalamic and peripherallevel, of 48-hour fasted wild-type or GHSR-null mice. In addition we studied theNeuropeptide Y (NPY) and GABA in the PVN and ARC of 48-hour fasted mice.