The effect of fasting on the ultrastructure of the hypothalamic arcuate nucleus in young rats.

In the present study, we described ultrastructural changes occurring in the neurons of the hypothalamic arcuate nucleus after food deprivation. Young male Wistar rats (5 months old, n = 12) were divided into three groups. The animals in Group I were used as control (normally fed), and the rats in Groups II and III were fasted for 48 hours and 96 hours, respectively. In both treated groups, fasting caused rearrangement of the rough endoplasmic reticulum forming lamellar bodies and membranous whorls. The lamellar bodies were rather short in the controls, whereas in the fasting animals they became longer and were sometimes participating in the formation of membranous whorls composed of the concentric layers of the smooth endoplasmic reticulum. The whorls were often placed in the vicinity of a very well developed Golgi complex. Some Golgi complexes displayed an early stage of whorl formation. Moreover, an increased serum level of 8-isoprostanes, being a reliable marker of total oxidative stress in the body, was observed in both fasting groups of rats as compared to the control.