Altered Fos immunoreactivity in the hypothalamus after glucose administration in pre- and post-weaning malnourished rats

The present study explored the effects of malnutrition and nutritional rehabilitation on the response to glucose in hypothalamic nuclei involved in metabolic homeostasis. Male Wistar rats were malnourished during gestation-lactation (MGL) or at weaning to 55 days (MPW). Two groups of rats were rehabilitated with a balanced diet until 90 days (MGL-R and MPW-R, respectively). After a glucose tolerance test (GTT), brains were processed for Fos immunoreactivity (Fos-IR). Both malnourished groups displayed hyperglycemia after GTT. MGL exhibited an increased number of Fos-IR neurons in the ventromedial hypothalamic nucleus (VMH), while MPW showed increased Fos-IR in the arcuate nucleus (ARC) and VMH and a decrease in the paraventricular nucleus (PVN), as compared with their controls. Nutritional rehabilitation normalized values of glucose after GTT in both groups, while low number of Fos-IR neurons remained in the ARC, PVN and VMH of MPW-R rats, indicating a deleterious, long-lasting effect after post-weaning malnutrition.