Effects of dietary on hypothalamic neuropeptide Y gene expression and obesity in rats

Objective To explore the effect of high-fat diet on the hypothalamic neuropeptide Y(NPY)expression and the mechanisms which predispose some individuals to become obese on high-fat diet.Methods Thirty-six female SD rats were randomly divided into high-fat diet group(n=27)and chow fed control group(n=9).After 13 weeks of either a high-fat diet or chew fed diet,the high-fat diet group was subdivided into Dietary Induced Obesity(DIO)and Dietary Induced Obesity Resistant(DIR)group according to the final body weight.Weight gain,food intake,and the concentration of plasma and hypothalamus neuropeptide Y were measured,and hypothalamic NPY mRNA expression were determined by RT-PCR.Results The levels of body weight,caloric intake,and the ratio of plasma and hypothalamus NPY were significantly higher in DIO group than in DIR or control group(P0.01),while no significant difference was found between DIR and control group(P0.05);hypothalamic NPY mRNA were increased in DIO group but not in DIR than control group.Conclusion On the High-fat diet,SD rats showed different susceptibility to obese and overeating,increased hypothalamic NPY were associated with their predispose to obese and overeating.