I am hoping to perform a lineage trace for a specific cell type, so the timing of Cre activation is very important. I have heard conflicting reports where some people claim tamoxifen will be cleared from the mouse by 4 days following the final injection while others believe it takes several weeks. Have any toxicology studies been performed to determine the timing of tamoxifen clearance in mice (mine are on a C57B6 background) and could someone provide a link to that study if it exists? I've had no luck finding anything. Thank you!
Hey Katherine,
Maybe I didn't understand what you are asking for, but I found both these studies in about 20 seconds.
Half-life of 16 hours according to this study.
Metabolites, pharmacodynamics, and pharmacokinetics of tamoxifen in rats and mice compared to the breast cancer patient.
Half-life of 12 hours according to this study.
Modification of gene activity in mouse embryos in utero by a tamoxifen-inducible form of Cre recombinase.
Dear Katherine Best,
In this study "Distribution of Tamoxifen and Its Metabolites in Rat and Human Tissues during Steady-State Treatment" CANCER RESEARCH 51, 4837—4844, September 15, 1991 it's possible to find your answer.
Best regrds
I think in addition to the literature, you could use antibodies to check for Cre expression, so you would know 1. how long does the expression last for and 2. how many cells express Cre vs how many cells express your transgene.
Hope this helps!
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