HYPOTHALAMIC NEUROPEPTIDE Y AND ITS RECEPTORS mRNA EXPRESSION IN DIET-INDUCED OBESE AND RESISTANT RATS

Objective: To investigate the effect of high-fat diet on expression of hypothalamic neuropeptide Y (NPY) and Y1, Y2, Y5 receptor in rats and the mechanism related to the susceptibility of obesity. Method:Thirty-six female SD rats were randomly divided into high-fat diet group (n=27) and control group (n=9), and fed for 13 w. Then the high-fat diet group was subdivided into dietary induced obese (DIO) and dietary induced obese resistant (DIO-R) group according to the final body weight. Body weight, visceral fat accumulation, caloric intake, energy efficiency were measured. RT-PCR was used to measure the expression of NPY, and Y1, Y2, Y5 receptor mRNA in hypothalamus. Results: Body weight, visceral fat accumulation, body fat percent, caloric intake, energy efficiency, and the expression of NPY and Y1, Y2, Y5 receptor of DIO group were higher significantly than those of control and DIO-R group, while no significant difference between DIO-R and control group, except that Y2 receptor was decreased in DIO-R group.Conclusion: The rats fed high-fat diet increased hypothalamic NPY and Y1, Y2, Y5 receptor expressions which were closely associated with predisposition to obese and overeating of DIO rats.