Soy isoflavone and its effect to regulate hypothalamus and peripheral orexigenic gene expression in ovariectomized rats fed on a high-fat diet.
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), 1200 ppm (M-SI) and 3600 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), melanin-concentrating hormone precursor (P-MCH), ghrelin, and leptin.


RESULTS
Compared with the OVX control group, the body weight and food intake in the H-SI 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.
Zhang
Yun-Bo
YB
Department of Environmental Hygiene, College of Public Health, Harbin Medical University, Harbin 150086, Heilongjiang, China.
Zhang
Yang
Y
Li
Li-Na
LN
Zhao
Xin-Yu
XY
Na
Xiao-Lin
XL
D000818:Animals; D004041:Dietary Fats / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D007031:Hypothalamus; D007529:Isoflavones / Q000737:chemistry* / Q000494:pharmacology*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D009765:Obesity; D010052:Ovariectomy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D013025:Glycine max / Q000737:chemistry*
D004041:Dietary Fats; D007529:Isoflavones; D009479:Neuropeptides; D012333:RNA, Messenger