Effects of cafeteria diet on the expression of neurosteroidogenic enzymes in hypothalamic nuclei involved in the control of food intake.

LAZZARINO GP; ACUTAIN MF; ANDREOLI MF; STOKER C; RAMOS J G

Mendoza

Workshop; International Workshop in Neuroendocrinology; 2015

Objectives: Cafeteria diet (CAF) is rich in highly palatable, energy dense foods that are prevalent in Western society. It induces slight obesity and increases energy intake through a neuropeptide mediated orexigenic signal of ventromedial (VMN) and paraventricular (PVN) nuclei. Steroids have a close relationship with the regulation of food intake: estradiol exerts an anorexigenic effect, whereas the administration of progestagens such as progesterone and allopregnanolone has the opposite effect. Little is known about the steroidogenic pathway in hypothalamus, especially in discrete nuclei and its role in food intake control remains unknown. Therefore, our aim was to determine the effects of cafeteria feeding on expression of steroidogenic enzymes and steroid receptors in three different hypothalamic nuclei involved in the control of food intake: arcuate nucleus (ARC), VMN and PVN. We also want to further study the relationship between energy intake and neurosteroids synthesis.Methods and Results: Female Wistar rats were fed with a control or CAF diet for 20 weeks since weaning. Animals were sacrificed, brains were extracted, sectioned into 300 µm slices and ARC, VMN and PVN were dissected using a 1 mm micro punch needle. Total RNA was isolated, reverse transcribed and amplified by real time quantitative PCR to assess levels of expression of steroidogenic enzymes [cytochrome P450 side chain cleavage (P450scc), 3beta-hydroxysteroid dehydrogenase (3beta-HSD), cytochrome P450 17alpha-hydroxylase (P450-17alpha), P450aromatase (ARO) and 5alpha-reductase-1 (5alphaR)] and receptors [estrogen receptor alpha (ERalpha and progesterone receptor (PR)] in the extracted nuclei. In ARC nucleus ERalpha and PR expression were increased by CAF diet (p