Physical activity and estrogen treatment reduce visceral body fat and serum levels of leptin in an additive manner in a diet induced animal model of obesity.

Estrogen replacement and physical activity have been demonstrated to reduce the risk to develop a metabolic syndrome in postmenopausal women. In this study we investigate the combined effects of endurance training and estrogen substitution in a rat animal model of diet induced obesity. Effects on lipid and glucose metabolism were evaluated. Ovariectomized (OVX) or sham-operated (SHAM) female Wistar rats were fed with a high fat diet (HF) for 9 weeks. After 3 weeks of overnutrition the OVX rats either remained sedentary, performed treadmill training, received 17β-Estradiol (E(2)), or combined treatment. The OVX rats had a greater increase in body weight and serum levels of cholesterol, triglyceride and low-density lipoprotein cholesterol (LDL). These parameters could be reduced by E(2) and more effectively E(2) in combination with exercise. Also the increase of visceral body fat and leptin could be improved by E(2) and exercise. This combination showed synergistic effects. Serum levels of insulin could be reduced by exercise training, E(2) substitution revealed no significant changes. Our results indicate that ovariectomy increases the susceptibility to develop obesity. In addition they show that the combination of hormone replacement therapy (HRT) and physical activity may influence parameters related to lipid metabolism positively in an additive manner. The results of this study provide evidence that the combination of HRT with physical activity could be a very effective strategy to prevent the development of a metabolic syndrome induced by overnutrition.