Aims and methods: 

The main regions of hypothalamus involved in food intake and energy homeostasis are the arcuate nucleus (ARC), paraventricular nucleus (PVN), ventromedial nucleus (VMH), dorsomedial nucleus (DMH) and lateral hypothalamic area (LHA). The PVN and DMH are involved in initiating and maintaining of food intake, VMH is considered as satiety and LHA as feeding centre. ARC is accessible to blood circulating signals of energy balance. In our study we used single Fos and double Fos-hypocretin (Fos-Hcrt) and Fos-oxytocin (Fos-OXY) immunostainings to identify neuronal activity in the above mentioned hypothalamic nuclei after 16 weeks of high fat diet (HF) consumption in C57Bl/6 male and female mice. HF diet contained 13, 60, and 27% calories as protein, fat, and carbohydrate, respectively.

Results: 

We observed noticable Fos activation of neurons in ARC, VMH and DMH in male vs. female mice independently to consumption of applied diet. On the other hand, prolonged HF diet lead to a significant rise of Fos in orexinergic Hcrt LHA neurons in female mice. The activity of anorexinergic OXY neurons in PVN was not altered in any genders.

Conclusion: 

These results may speak out for gender differences in the activity of hypothalamic nuclei regulated food intake and energy balance, which can be in female ones further altered by prolonged HF intake.

This study was supported by VEGA grant 2/7003/7.