PT - JOURNAL ARTICLE AU - Sofia Movérare AU - Johanna Dahllund AU - Niklas Andersson AU - Ulrika Islander AU - Hans Carlsten AU - Jan-Åke Gustafsson AU - Stefan Nilsson AU - Claes Ohlsson TI - Estren Is a Selective Estrogen Receptor Modulator with Transcriptional Activity AID - 10.1124/mol.64.6.1428 DP - 2003 Dec 01 TA - Molecular Pharmacology PG - 1428--1433 VI - 64 IP - 6 4099 - http://molpharm.aspetjournals.org/content/64/6/1428.short 4100 - http://molpharm.aspetjournals.org/content/64/6/1428.full SO - Mol Pharmacol2003 Dec 01; 64 AB - It was recently reported that the synthetic compound estren increases bone mass without affecting reproductive organs or classic transcription. The aim of the present study was to further characterize the in vivo and in vitro effects of estren. We demonstrate that estren is a selective estrogen receptor modulator (SERM) with a strong effect on thymus, a moderate effect on uterus and trabecular bone, but no major effect on fat or cortical bone in 11-month-old ovariectomized mice. The effect of estren on trabecular bone and uterus is mediated via estrogen receptors (ERs) because no effect is seen in ER double-inactivated mice. Furthermore, with the use of ERα- and ERβ-expressing reporter cell lines, we demonstrate that estren displays an agonistic effect on transcriptional activity of an estrogen-responsive element-driven reporter gene with a degree of agonism similar to that of 17β-estradiol for both ERα and ERβ. Thus, estren has the capacity to exert genomic effects via both ERα and ERβ. We conclude, in contrast to what was previously reported by others, that estren is a SERM with transcriptional activity.