The Effect of Neuropeptide Y and Norepinepherine on Food Intake and Body Weight

摘要

NPY has been reported to co-exist within catecholaminergic neurons of the central and peripheral nervous systems. The functional significance in noradrenergic neurons has been related to the vasomotor effects of NPY which complement and interact with NE which is known to have central and peripheral effects on resting metabolic rate (RMR), food intake and body weight of rats. We have studied the effect of chronic peripheral administration of NPY on the metabolic action of NE in lean and obese adult male rats. A group of 20 adult male obese (Jaffa) Zucker rats were acclimated to environmental temperature of either 28°C or 17°C. Each group was divided into 5 subgroups: (I) untreated controls; (II) Carrier-treated Controls; (III) NPY treated; (IV) NE treated and (V) NPY+NE treated. In subgroups II-V , Alzet~(Tm) (2002) osmotic minipumps were implanted under the skin in the interscapular region. Pumps were filled with carrier alone (subgroups II) plus NPY (subgroups III), or NE (subgroups IV), or both (subgroups V). Delivery rates were calculated to be 03 ug/h NPY ; 20 ug/h NE, extending over a period of 14 days. Starting from day 2, cumulative food intake and cumulative changes in total body weight were measured every two days.. In warm environmental the combined treatment with NE and NPY was the only treatment that caused significant reduction of total body weight by inhibiting food intake. In the cold environment the NE and NPY together showed similar but less enhancing effect on body weight, this was mainly due to the significant depression of food.