Evidence for functional estrogen receptors α and β in human adipose cells: regional specificities and regulation by estrogens

Abstract

Adipocytes are estrogen-responsive cells, but the quantitative expression and transcriptional regulation of the estrogen receptors (ER-α and ER-β) in human adipocytes and their precursor cells are unclear. Using real-time quantitative PCR, we have demonstrated that both ER-α and ER-β mRNA are expressed in human mature adipocytes with a large predominance of ER-α mRNA. Moreover, ER-α mRNA is identically expressed whatever the anatomic origin (intraabdominal and subcutaneous) of the adipocytes and the gender. ER-β mRNA levels are higher in women compared with men, without regional differences. 17β-Estradiol in vitro upregulates expression of both ER-α and ER-β mRNA in subcutaneous adipocytes from women but only the ER-α mRNA in subcutaneous and intra-abdominal adipocytes from men. In preadipocytes, only the ER-α subtype was present. In the latter cells, estrogens in vitro had no influence on ER-α expression (mRNA and protein). The present study also shows that estrogens in vitro increase the AP-1, SP-1, and estrogen response element DNA binding activities in differentiated but not in confluent preadipocytes, suggesting that ER become functional during the course of adipogenesis. On the whole, these data are consistent with a predominant role of the ER-α subtype in mediating the effects of estrogens on human adipose tissue development and metabolism.