Refeeding after 72 hour fasting alters neuropeptide Y and monoamines in various cerebral areas in the rat.

1. Monoamine turnover and neuropeptide Y (NPY) levels were evaluated in the CNS of adult male rats either after fasting (72 hr) or refeeding. 2. In the fasted group, an overall increase in NPY levels was observed except in the striatum where it was decreased. The serotoninergic turnover was decreased in the hippocampus, striatum and cortex. 3. After refeeding, NPY decreased in the hypothalamus and cortex but was further increased in the hippocampus and decreased in the striatum. The serotoninergic turnover was still decreased in the hippocampus and cortex. The norepinephrine levels and the dopaminergic turnover increased in the hippocampus and cortex. 4. No relationship appeared between NPY and monoamine changes suggesting that NPY can act independently in feeding behavior, and play, in different brain areas, an important role in its regulation.