Tamoxifen, 5g

Supplied by STEMCELL Technologies as a 5 g powder, this selective estrogen receptor modulator (SERM) supports routine laboratory studies of estrogen-dependent signaling and conditional gene editing. Tamoxifen is most commonly used to activate CreER recombinases in transgenic mouse models, allowing researchers to time deletion of floxed alleles in specific tissues after systemic administration. The compound is also a reference tool in breast cancer research, where it is applied to MCF-7 and T47D cell cultures to probe ER-alpha signaling, tamoxifen resistance, and combined endocrine-chemotherapy responses.

For animal dosing, the powder is dissolved in corn oil or sunflower oil at 10 to 20 mg/mL and given by intraperitoneal injection, commonly at 75 mg/kg for 5 consecutive days to induce Cre activity in conditional knockout studies. In vitro, a 1 mM stock in absolute ethanol is typical and is stored at -20 °C protected from light to minimize trans-isomer formation. The 5 g unit supports long dosing cohorts, repeated in vivo experiments, and serial dose-response work; freshly weigh aliquots into amber vials if you anticipate repeated freeze-thaw cycles. Confirm identity and activity against the certificate of analysis prior to large studies. For research use only.