Feed intake regulating neuropeptides and apoptosis in the healthy bovine hypothalamus

The feed intake regulating neuropeptides and hormones are located mainly in the hypothalamus of animals. However, it is unclear how the appearance of these factors is correlated with programmed cell death that regulates cellular balance in healthy animals. Thus, the relative densities of dynorphin-, ACTH-, NPY-, and galanin-containing cells simultaneous with apoptosis were investigated by immunohistochemistry and TUNEL method in 12, 4-6 years old lactating healthy cows. A few to moderate numbers of dynorphin-, NPY- and galanin-containing cells, but moderate to numerous ACTH-containing cells in hypothalamic nuclei were seen. Additionally, apoptosis affected numerous cells in all locations including the grey and white matter of the brain, endothelial cells of blood vessels, and in the hypothalamic nuclei. Thus we suggest that the relatively scarce appearance of feed intake neuropeptides such as dynorphin, NPY and galanin, but a rich distribution of ACTH in the hypothalamic nuclei based on the abundance of apoptosis in all structures of healthy bovine brains. These processes characterize the hypothalamus of animals between feed intakes and seem not to correlate with each other.