Effects of palatability-induced hyperphagia and food restriction on mRNA levels of neuropeptide-Y in the arcuate nucleus

This study examined the effect of feeding either a bland cornstarch-based diet (BCD) or a highly palatable, high fat diet containing sucrose (HPD) on hypothalamic arcuate nucleus (ARC) gene expression for neuropeptide-Y (NPY). Male Sprague-Dawley rats received either BCD ad libitum, HPD ad libitum, HPD pair-fed to the caloric intake of the BCD, or the HPD at 60% of ad libitum HPD intake for 7 days. Animals receiving the HPD ad libitum consumed more calories and gained more weight than animals receiving the BCD (P < 0.001). The HPD did not affect ARC NPY mRNA levels, whether the subjects were allowed to overeat or pair-fed to the BCD (P > 0.05). However, feeding the HPD at 60% of ad libitum intake of the HPD, increased NPY mRNA levels in the ARC relative to the other treatments (P < 0.01). The present data are consistent with the view that NPY in ARC responds to energy deficits rather than to hyperphagia stimuli related to palatability. (C) 1998 Elsevier Science B.V. All rights reserved.