Combinatory effects of phytoestrogens and exercise on body fat mass and lipid metabolism in ovariectomized female rats

The purpose of this study was to investigate the combinatory effects of an isoflavone (ISO)-rich diet and exercise on fat mass and lipid metabolism in ovariectomized (OVX) rats. Therefore the female Wistar rats were sedentary, performed an intense treadmill uphill running, received ISOs, or a combination of ISOs and running after ovariectomy. The exercise reduced visceral fat mass, adipocyte size and serum leptin in Sham animals and antagonized the increases of these parameters induced by OVX. ISOs reduced OVX induced increase of serum leptin. The combination of training and ISOs was most effective in reducing serum triglyceride levels. In OVX rats the training stimulated the expression of genes associated with fatty acid synthesis (SREBP-1c and FAS) in adipose tissue, soleus muscle, liver and genes associated with fatty acid oxidation (PPARδ and PGC-1α) in adipose tissue. ISOs stimulated the expression of SREBP-1c and FAS in soleus muscle and PGC-1α in adipose tissue, whereas suppressed hepatic SREBP-1c and FAS expression. Strong additive effects of ISOs combined with the training were observed for PPARδ and PGC-1α expressions in soleus muscle. In conclusion our results demonstrate that both the training and ISOs affect fat mass and fatty acid metabolism in OVX rats. The training seems to have a higher impact than ISO exposure in regulating gene expression in adipose tissue. However, the strongest effects for several of the addressed parameters could be observed in the combination group especially in the soleus muscle. Therefore a combination of training and an ISO-rich diet may have beneficial effects on fatty acid metabolism and could be a concept for the prevention of obesity in postmenopausal females.