Objective To explore the effect of soy isoflavone on obesity in the light of hypothalamus and peripheral orexigenic gene regulation. Methods Fifty-four female rats were randomly assigned to 6 groups： one sham-operated group （SHAM）, one ovariectomized （OVX） control group, three OVX groups fed with 400 ppm （L-SI）, 1 200 ppm （M-SI） and 3 600 ppm （H-SI） isoflavone respectively, and one OVX group receiving 0.45 ppm diethylstilbestrol （EC）. All rats were allowed to take high-fat diet for 4 weeks. Some neuropeptides were measured by RT-PCR. These neuropeptides included NPY, pro-opiomelanocortin （POMC）, cocaine and amphetamine regulated transcript （CART）, orexin, melanin-concentrating hormone （MCH）, ting hormone precursor （P-MCH）, ghrelin, and leptin. Results Compared with the OVX control group, the body weight and food intake in the H-S1 group were reduced significantly and there was a significant dose-dependent manner in the 3 isoflavone groups. The results of RT-PCR showed that the NPY level in the 3 isoflavone groups was significantly increased and the POMC/CART gene expression decreased significantly in rats＇ hypothalamus compared with that in the OVX control group. However, the expression of orexin, MCH and P-MCH had no change. The peripheral grelin mRNA expression was higher in the 3 isoflavone groups, while leptin gene expression in the fat was not consistent. Conclusions This research showed that isoflavone could prevent obesity induced by high-fat diet and ovariectomy through regulating hypothalamus and peripheral orexigenic gene expressions associated with food intake.
YUN-BO ZHANGYANG ZHANGLI-NA LIXIN-YU ZHAOXIAO-LIN NA
