Lovisa Lundholm1, Sofia Movérare2, Knut R. Steffensen1, Maria Nilsson1, Michio Otsuki1, Claes Ohlsson2, J.-Å. Gustafsson3, Karin Dahlman‐Wright1
1Department of Biosciences at Novum, Karolinska Institutet, SE-141 57 Huddinge, Sweden
2Department of Internal Medicine, Division of Endocrinology, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden
3Houston Methodist
Tóm tắt
Estrogens reduce adipose tissue mass in both humans and animals. The molecular mechanisms for this effect are, however, not well characterized. We took a gene expression profiling approach to study the direct effects of estrogen on mouse white adipose tissue (WAT). Female ovariectomized mice were treated for 10, 24 and 48 h with 17beta-estradiol or vehicle. RNA was extracted from gonadal fat and hybridized to Affymetrix MG-U74Av2 arrays. 17beta-Estradiol was shown to decrease mRNA expression of liver X receptor (LXR) alpha after 10 h of treatment compared with the vehicle control. The expression of several LXRalpha target genes, such as sterol regulatory element-binding protein 1c, apolipoprotein E, phospholipid transfer protein, ATP-binding cassette A1 and ATP-binding cassette G1, was similarly decreased. We furthermore identified a 1.5 kb LXRalpha promoter fragment that is negatively regulated by estrogen. Several genes involved in lipogenesis and lipolysis were identified as novel targets that could mediate estrogenic effects on adipose tissue. Finally, we show that ERalpha is the main estrogen receptor expressed in mouse white adipose tissue (WAT) with mRNA levels several hundred times higher than those of ERbeta mRNA.
