Harlan Teklad 他莫昔芬动物饲料 Tamoxifen diets
Diets with tamoxifen activate CreER
Several references cite use of tamoxifen-containing diets for models with Cre under the control of a mutated estrogen receptor. Envigo Teklad diets makes a variety of tamoxifen-containing diets customized to meet your research needs. We also make a variety of doxycycline-containing diets for tet regulated systems. If you have any questions, don’t hesitate to consult a nutritionist.
Teklad stocks tamoxifen and tamoxifen citrate
Tamoxifen is added to the diet as a tamoxifen-sucrose mixture. Users are encouraged to use the stocked supply. However, Teklad will continue to work with customer prepared mixes. If you choose this option, please consult a nutritionist for additional information about preparing and sending the mixture.
Users are encouraged to select from the stocked options below supply readily available to ship within days.
|Teklad offers diet with USP grade tamoxifen and tamoxifen citrate|
mg per kg diet
mg per kg body weight1
(Teklad supplied tamoxifen)
1 Assumes 20-25 g body weight and three-four g intake
2 Tamoxifen citrate is 66% tamoxifen
3 Referred to as TAM400/CreER in Europe (TD.55125)
Please add 5-10 day lead time for irradiated diets; minimum 3 kg orders are required for stocked and customized items.
These diets all have tamoxifen premixed with ~five percent sucrose as a palatability enhancer; however, feed aversion may still occur. If intake is a problem, see below for advice.
Teklad Global 2016 — base diet in these examples — is only one of several minimal phytoestrogen diets Teklad produces. Consult a nutritionist about use of other base diets.
Key planning information
- Minimum order quantity is three kg, sufficient for feeding ~20 mice for one month
- Store diet refrigerated and plan to use within six months
- Typical lead time is two weeks (four weeks if irradiated)
- Irradiation (optional) minimal dose of 20 kGy (Must be requested at time of order)
- To place an order: contact Teklad Customer Service at 800.483.5523 or initiate order online
Mice need time to adjust
- Initial reduction in food intake and weight loss
- Daily observation of animal tolerance — consult your IACUC for monitoring metrics
- Intervene when necessary
Other researchers have the following advice
If intake seems to be a problem:
- Determine if a lower dose is effective for your model by conducting a tamoxifen dose feeding trial
- Gradually acclimate mice by mixing tamoxifen-containing pellets with regular feed pellets
- Wet the food, then place in a dish inside the cage (requires daily replacement)
- Feed tamoxifen diet on weekdays, regular diet on weekends
- Alternate weeks (two weeks on tamoxifen diet, one week off) for longer treatments
Safe handling of tamoxifen diets
- Tamoxifen is a selective estrogen receptor modulator (SERM) meaning it can repress actions of estrogen or have pro-estrogen effects
- Usual dose for therapeutic effects in humans is 20 mg/day. Tamoxifen diets for rodents typically contain ~one to two mg/pellet
- Accidental tamoxifen exposure can be minimized by using typical lab precautions of lab coat, gloves, and mask when handling the diet.
- Your chemical safety department should be contacted for additional institution specific guidelines for handling and disposal of tamoxifen containing diets.
Key points from literature
- Length of treatment varies from one to two weeks1,2,5,6,7,8 to one to two months3,4,8
- Pure tamoxifen1,5,8 and tamoxifen citrate1,2,3,4,6,7 are both effective
- Usual tamoxifen doses are ~40-80 mg per kg body weight per day
- Typical inclusion for pure tamoxifen is 250 mg8 or 500 mg1,5 and for tamoxifen citrate is 400 mg per kg diet1,2,3,4,6,7
- Initial weight loss of ten % is reported1,2,4,7,8, associated with reduced food intake2
- Subsequent recovery of body weight after returning to regular diet may be compromised by gene inactivation2,7
Selected tamoxifen references
- Andersson KB, Winer LH, Mork HK, Molkentin JD, Jaisser F. 2010. Tamoxifen administration routes and dosage for inducible Cre-mediated gene disruption in mouse hearts. Transgenic Res 19:715-725.
- Chiang PM, Ling J, Jeong YH, Price DL, Aja SM, Wong PC. 2010. Deletion of TDP-43 down-regulates Tbc1d1, a gene linked to obesity, and alters body fat metabolism. Proc Natl Acad Sci USA 107:16320-16324.
- Kardakaris R, Gareus R, Xanthoulea S, Pasparakis M. 2011. Endothelial and macrophage-specific deficiency of P38alpha MAPK does not affect the pathogenesis of atherosclerosis in ApoE-/- mice. PLoS One 6:e21055.
- Kiermayer C, Conrad M, Schneider M, Schmidt J, Brielmeier M. 2007. Optimization of spatiotemporal gene inactivation in mouse heart by oral application of tamoxifen citrate. Genesis 45:11-16.
- Koitabashi N, Bedja D, Zaiman AL, Pinto YM, Zhang M, Gabrielson KL, Takimoto E, Kass DA. 2009. Avoidance of transient cardiomyopathy in cardiomyocyte-targeted tamoxifen-induced MerCreMer gene deletion models. Circ Res 105:12-15.
- Kratsios P, Catela C, Salimova E, Huth M, Berno V, Rosenthal N, Mourkioti F. 2009. Distinct roles for cell-autonomous Notch signaling in cardiomyocytes of the embryonic and adult heart. PCirc Res 106:559-572.
- Miro-Murillo M, Elorza A, Soro-Arnaiz I, Albacete-Albacete L, Ordonez A, Balsa E, Vara-Vega A, Vazquez S, Fuertes E, Fernandez-Criado C, Landazuri MO, Aragones J. 2011. Acute Vhl gene inactivation induces cardiac HIF-dependent erythropoietin gene expression. PLoS One 6:e22589.
- Welle S, Burgess K, Thornton CA, Tawil R. 2009. Relation between extent of myostatin depletion and muscle growth in mature mice. Am J Physiol Endocrinol Metab.Oct;297(4):E935-40.