Abstract: Objective To explore whether estrogen is involved in the regulation of weight homeostasis and impacts of estrogen on expression levels of aquaglyceroporin(AQP).Methods Female Sprague-Dawley(SD) rats were randomly divided into four groups(n=8 for each group):a sham-operated group(SO), and three ovariectomized groups(OVX).Four weeks after the operation, the rats were administrated with corn oil(SO), corn oil(OVX), 100 μg/kg 17β-estradiol(E2)(OVXE1) and 400 μg/kg E2(OVXE2) via subcutaneous injection for 2 weeks.The body weight and food consumption were monitored.The levels of glucose in blood were detected with glucometer.The mRNA expression levels of AQP and silent information reguloaor 1(Sirt 1) in parametrial adipose tissues and liver were determined with real-time PCR method.Results The OVX rats(330.44±25.09 g) weighed heavier than SO rats(287.44±13.18 g), with a statistically significant difference(t=3.71, P<0.05).The organ coefficient of parametrial adipose tissues was greater in OVX rats(1.55±0.48) than that in SO rats(0.93±0.19)(t=2.79, P<0.05).The glucose level in OVX rats reached the maximum(11.30±0.50 mmol/L) in 90 min after glucose gavage, which was significantly higher than that in SO rats(8.23±1.39 mmol/L)(t=3.60, P<0.05).The AQP9 expression level in liver significantly increased in OVX rats(1.37±0.17) than that in SO rats(1.04±0.10)(t=3.86, P<0.05).Administration of E2 to OVX rats significantly reduced the food consumption, body weight, and the expression levels of AQP7 in parametrial adipose tissues and AQP9 in liver.Conclusion Estrogen deficiency induces weight gain, while estrogen replacement could reverse it.Estrogen may participate in the regulation of weight homeostasis by influencing food intake, affecting insulin sensitivity, and modifying expression levels of AQP.