雌激素通过瘦素信号通路途径调节脂肪细胞代谢生成

Postmenopausal women often present obvious body composition changes under the absence of estrogen, including overweight, obesity and android-like body fat distribution, therefore poses serious threaten for women's health. Although the intimate relationship between estrogen and body appearance have been noticed, mechanism remains unclear. We assumed that estrogen may regulate fat distribution through affecting leptin signal pathway, which has been shown playing major role in energy homeostasis. To test this hypothesis, we randomized female SD rat into ovariectomy (OVX) and sham group, and then collected adipose tissue around genital, retroperitoneal and subcutaneous after 14 week. Leptin receptor expression in adipose tissue was measured by western blot. Results indicated that leptin receptor were significantly down-regulated in ovariectomy group, especially in fat around genital. Weight changes were observed every week, repeated measures analysis of variance showed that OVX group has higher weight gain compared with sham group during the 3 month (P< 0.001), and so does the Lee's index (P< 0.001), which were calculated at the end of the study. We further used mesenchymal stem cells (MSCs), the progenitor of Adipocytes as an in vitro model to figure out the effect of estrogen on leptin receptor expression. After MSCs were treated by increasingconcentration of 17-βestradiol and letpin respectively, QPCR were used to test the mRNA expression of leptin receptor subtype, OBRb (long form) and OBRa (short form). Negative correlation was noticed between estrogen concentration and leptin receptor subtype expression. Similar tendency were also observed in leptin treatment group. Besides, the expression of leptin in MSCs was degrading accompaied with increasing concentration of estrogen, and PPARγ, the indicator of adipogenisis, was also supressed under treatment of estrogen. Estrogen may act on leptin receptor expression to influence the body composition in postmenopausal women. And the similar molecular mechanism of estrogen and leptin shows that these two hormones probably have synergistic effects on energy metabolism.