Impact of the ghrelin signaling on food intake after a fasting event

GIMENA FERNANDEZ; AGUSTINA CABRAL; ALEXANDRA LABARTHE; GUADALUPE GARCÍA ROMERO; MARÍA FLORENCIA ANDREOLI; FLORENCIA ACUTAI; MIRTA REYNALDO; GUILLERMO RAMOS; VIGINIE TOLLE; JACQUES EPELBAUM; MARIO PERELLÓ

Congreso; 2nd FALAN Congress; 2016

Refeeding after a period of severe fastingtriggers a robust hyperphagia, which persists even afteranimals have reached their energy needs. Plasmaghrelin levels and the hypothalamic geneexpression of the ghrelin receptor (orgrowth hormone secretagogue receptor, GHSR) increaseduring fasting in order tocope with the negative energy balance condition. Here, we investigatedthepotential modulatory role of the ghrelin system on the compensatory hyperphagiathat displaymice that have been exposed to a 48h fasting period. Usingautomated feeding/activity stations inmice exposed to a fast-refeedingparadigm, we found that refed wild-type mice display a significantincrease ofthe total food intake that continues for 6 days after refeeding. GHSR-deficientmice alsoshow a compensatory hyperphagia, which was significantly smaller thanobserved in wild-type mice.Fasted wild-type mice show an increase of plasmaghrelin levels as well as an increase of theGHSR levels in the hypothalamicarcuate nucleus, as indicated by both a ghrelin binding assay andgeneexpression analysis. Notably, plasma ghrelin levels return to basal levels 1day after refeedingwhile hypothalamic GHSR levels seems to remain increasedeven after 4 days of refeeding. Thus,we conclude that the ghrelin system playsa modulatory role on the magnitude of the hyperphagiaobserved after a severefasting period.