Insulin, transferrin and selenium.

Blog entry

Many labs take advantage of a medium supplement that is both necessary for healthy cell cultures, and saves time and effort.  This cocktail consist of insulin, transferrin, and selenium, or as most of us know it, ITS (pronounced I-T-S). We already spoke about insulin so now we’ll talk about the other two: Transferrin and selenium.

Transferrin is a molecule that cells need in order to process iron, a critical mineral to cellular metabolism.  As its name implies, transferrin’s role is essentially to transfer iron from the outside, to the inside of cells. It does this by first binding to iron, then to a cell’s transferring receptor, and helping it pass the cells’ membrane, via receptor-mediated endocytosis. Most cell biologists are familiar with two types of transferrin: Holo-transferrin, and apo-transferrin.  APO-transferrin is not bound to iron molecules but willing and ready to do so in the cell culture dish, and if your cultures have serum in it, there will be plenty of Fe to go around. Holo-transferrin, is already bound to iron, and is used in cultures with low levels of iron as a supplement.  This is especially important when you’re looking for transferrin for your serum-reduced or serum-free cultures. 

Selenium is a trace element that essentially acts as an anti-oxidant in our bodies. It has the same job in cell culture environments. Most often sold as sodium selenite, this mitochondria-saver is a critical component of ITS. While the other two ingredients drive and promote metabolism, this one keeps the metabolism-induced toxins down. When cells metabolize, they generate reactive oxygen species, which is very damaging to cells. Antioxidants like selenium help neutralize this reactive oxygen and keep the cells healthy.  Same thing for your body, which is why I took it upon myself to search for foods high in selenium. Can’t hurt. Ever since I saw a seminar on how blueberry juice can help protect neural stem cells, I figured there may be something to this whole “healthy food” thing. Here’s what I found:
Brazil nuts are PACKED with selenium.  Canned tuna and cod also have a bunch of it. Then, as we go lower in selenium content we see meats, pastas and sunflower seeds, followed by rice and cheese. Finally, my super-sleuthing skills gave me even more reason to clog my arteries: Bacon has the 8th highest selenium content, according to these folks:

Gemini has all three of these components separately, or together in an ITS vial. Feel free to give them a call and request a sample. They’re happy to oblige! They won’t ship bacon samples, though. I asked.


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