Tamoxifen administration to mice
One of the uses of tamoxifen in the lab is the activation of enzymes deactivated via an estrogen-binding domain, like Cre-ER (Cre-LBD). Tamoxifen is an estrogen analogue that binds with higher affinity than estrogen to altered estrogen binding domains.
Tamoxifen is administered to mice in 2 main ways: via the drinking water or in an oily mix given via a feeding needle. Administration via the drinking water is easier but somewhat less reliable.