CAFETERIA DIET CAUSES OBESITY WITHOUT METABOLIC SYNDROME ALTERING THE EXPRESSION OF NEUROPEPTIDES IN DIFFERENT HYPOTHALAMIC NUCLEI INVOLVED IN FOOD INTAKE CONTROL

LAZZARINO, GISELA P; ACUTAIN, M. FLORENCIA; ANDREOLI, M. FLORENCIA; STOKER, CORA; RAMOS, JORGE G

Workshop; 3rd Latin American International Workshop in Neuroendocrinology (IWNE 2015); 2015

CAFETERIA DIET CAUSES OBESITY WITHOUTMETABOLIC SYNDROME ALTERING THE EXPRESSION OF NEUROPEPTIDES IN DIFFERENTHYPOTHALAMIC NUCLEI INVOLVED IN FOOD INTAKE CONTROL Authors:Lazzarino, Gisela P.; Acutain, M. Florencia; Andreoli, M. Florencia; Stoker,Cora; Ramos, Jorge G. Affiliations:Departamento de Bioquímica Clínica y Cuantitativa, Facultad de Bioquímica yCiencias Biológicas, Universidad Nacional del Litoral. Instituto de Salud y Ambiente del Litoral (ISAL),Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral- CONICET. Objectives: The hypothalamus receives and translates signalsrelated to energy status,producing orexigenic (agouti-related peptide, AgRP and neuropeptide Y, NPY) and anorexigenic (pro-opiomelanocortin,POMC and cocaine and amphetamine regulated transcript, CART) peptides. Kisspeptin (kiss) is a neuropeptide that stimulates POMC and inhibits NPY expression. We aimed to evaluate these systems in three different hypothalamic nuclei: arcuate nucleus (ARC), ventromedialnucleus (VMN) and paraventricular nucleus (PVN) in anexperimental obesity model induced by cafeteria diet (CAF), prevalent inWestern society.Methods and Results: Female Wistar rats were fed a control or a CAF dietfrom weaning and for 20 weeks. During this period food consumption and body weightwere monitored. At week 19 a glucose tolerance test (GTT) was carried out. Oneweek after, animals were sacrificed and the brain, fat pads and blood wereextracted. Serum was separated and triglycerides, cholesteroland insulin were assessed. Brains weresectioned into 300 µm slices and ARC, VMN and PVN were dissected using a 1 mmmicro punch needle. The mRNA expression of insulin receptor (IR), kiss, POMC, CART, AgRP and NPY werequantified by real time PCR in the extracted nuclei.Cafeteria feeding induced obesity demonstrated byincreased body weight (9,8%, p<0.01) and fat depots (44,7%, p<0.00001), whichis related to an increment in energy intake (21%, p<0.00001) withouthyperphagia. Triglycerides, cholesterol, insulin, glucose andGTT were not altered by the treatment. In ARC nucleus POMC and kiss expression was increased by CAFdiet (p<0.05; p<0.01, respectively) while AGRP was reduced (p<0.05).In VMN nucleus only AGRP showed an increment (p<0.05). Meanwhile, in PVN nucleus AGRP and NPY expressionrose (p<0.05) and kiss was notdetectable. IR was not altered in any nucleus.Conclusions: Although CAF fed rats were not hyperphagic, energyintake and body weight were increased without metabolic syndrome. The incrementin energy intake was related to an orexigenic signal of VMN and PVN, given bythe increment in the expression of AGRP and NPY. This action was mildlycounteracted by the reduced AGRP and increased POMC in ARC, presumably alongwith the higher activity of kiss inthis nucleus. The orexigenic response in PVN and VMN might correspond with thelack of changes in kiss expression. Financial Support: UniversidadNacional del Litoral and Argentine National Agency for the Promotion of Scienceand Technology (ANPCyT)