Induction of neuropeptide Y expression in dorsomedial hypothalamus of diet-induced obese mice

ALTERATIONS of hypothalamic neuropeptide Y(NPY) and melanocortinergic funct ions in diet-induced obese (DIO) C57BL/6J mice were investigated by in situ hybridization. Compared with controls, the DIO mice displayed a profound i nduction (similar to 40-fold) of NPY expression in the dorsomedial (DMH) an d ventromedial (VMH) hypothalamic nuclei, whereas the level of NPY mRNA in the arcuate nucleus (ARC) was reduced by 44%. The expression of pro-opiomel anocortin (POMC) and agouti-related protein was not significantly altered i n the ARC of obese mice. Both excess body weight gain and altered hypothala mic NPY expression were reversible. We propose that the highly induced NPY expression in DMH and/or VMH may be a contributing etiological factor for t he development of obesity and leptin resistance in the DIO mice. (C) 1998 L ippincott Williams & Wilkins.