The Effect of Ovariectomy and Estrogen Replacement on Body Weight and Visceral Adipose Tissue in Rats

Estrogen deficiency is associated with unfavorable changes in body composition and abdominal fat deposition. The consequences of these changes lead to metabolic abnormalities and differential fat distribution. Seventy female Wistar rats (weight: 170.73±15.82gr mean±SD) were divided into 7 groups:Intact(one group),sham (two groups), ovariectomized (two groups), ovariectomized, receiving estradiol valerate(one group) and ovariectomized, receiving sesame oil (one group).The intact rats were anesthetized and visceral fat was then taken from the abdominal cavity and weighed immediately. Two weeks after operation, one group of ovariectomized rats and one group of sham rats were sacrified and visceral fat was measured. The estradiol receiving ovariectomized group and vehicle group were given equal volumes of 17β-estradiol(30μg/kg, sc, 5 d/wk) and sesame oil for 8 weeks, respectively. After 8 weeks, all animals were sacrificied and intra- abdominal fat depots were dissected and weighed. Data were analyzed with one-way ANOVA and post-hoc and using paired t test. The differences were considered significant at P<0.05. After two weeks of surgery, the ovariectomized rats showed insignificant increase in body weight and visceral fat weight, whereas, after eight weeks, body weight increased significantly in ovariectomized rats (P<0.05). Estradiol replacement decreased body weight and visceral fat weight, however this decrease was only significant in body weight(P<0.05). The results indicate that estrogen deficiency following ovariectomy leads to increase in both body weight and visceral fat, showing that replacement of this hormone could decrease body weight without affecting visceral fat.