GemBlog – Insulin: Pig? Bovine? Human? What am I supposed to be using?
Insulin is a peptide hormone. Specifically, it is a 51 amino acid peptide with a molecular weight of 5.8 kDa. Together with other hormones, it regulates our body’s metabolism and is essential for regulating fat and carbohydrate (sugar) metabolism. It is made by the pancreas and removes the glucose from the blood stream by storing it in our muscle, liver, and fat cells as glycogen. Basically, it allows our cells to take up glucose and store it for future use, keeping our blood free from excess sugars.
Cell biologists often use insulin in their cultures as a supplement to help the cells regulate their metabolism. After all, most folks don’t have pancreatic cells in their culture dishes. Researchers do, however, have a variety of options for their insulin. As I mentioned last week, insulin-for-the-lab usually comes as a lyophilized powder. While getting it into a working solution may not be an issue, some folks may find themselves wondering which insulin is best for their cultures.
Insulin, being a critical component of normal metabolism, is a very highly conserved protein. The difference in amino acid sequence is minimal between human and bovine (it’s just 3 amino acids) but most people swear by one or the other for their cells, usually for good reason. Which one to try? A rule of thumb that I have followed was simply to use the same insulin my lab mates or predecessors used. If the cells were happy, why stir the pot? In my case, it was bovine insulin which nowadays, is not such an easy thing to find. More and more suppliers are discontinuing it, or have the stuff backordered until the cows come home (I know. Terrible. But I’m a scientist not a comedian. Gemini has other folks who excel in that department, but I digress…). Essentially, it may look as if bovine insulin is being phased out. Or, it could be that the three amino acid residue difference between human and bovine insulin is inconsequential for the role(s) insulin plays in mammalian cell culture systems. As a matter of fact, bovine insulin was once used to treat diabetic patients. So why the big decision on which to use? Well, cells acclimate pretty quickly to their surroundings. If they’ve been in culture condition long enough, they may react differently to different insulins. If your HeLa cells have been exposed to bovine insulin since your P.I. started the lab, then you may want to keep giving them bovine insulin. Same goes for human recombinant insulin.
Gemini is one, if not the only supplier of bovine insulin powder for your cell culture needs. They have plenty and they expect to have plenty of it for a good long time. No backorders, no substitutes or alternatives, just the same bovine insulin our cells have been utilizing. Give ‘em a call and see what they can do for you.