Glycogen and Glucagon: Managing Your Self-Storage Unit
There’s an element of type 2 diabetes we don’t talk about much. We do talk a lot about carbohydrates, how digesting carbohydrate food makes blood glucose levels go up. We talk a lot about insulin too, how insulin normally stimulates certain cells to “absorb” glucose, bringing blood glucose levels back down, and how those cells become resistant to insulin in type 2 diabetes. We don’t often talk about what happens to the glucose that does get absorbed into cells, and how that story is an important part of diabetes too. And, it’s a story about your brain.
Having some glucose available in your blood is essential to keep your brain operating – that’s why there is a “normal” blood glucose level. Your brain must have glucose to fuel its constant activity, and your brain uses a lot of glucose. So, you might wonder why your brain doesn’t run out of fuel unless you keep eating a steady stream of carbohydrate foods. That’s a story about your glucose self-storage unit – your liver.
Much of the glucose that is absorbed into cells with the help of insulin is stored away. In liver cells, glucose is packed away in starch molecules called glycogen, and that makes your liver an extremely important storage unit. When blood glucose levels begin to drop, as your brain and muscles use the glucose fuel, a hormone called glucagon causes your liver to unpack glycogen and release glucose into your bloodstream. Glucagon causes blood glucose levels to rise, an opposite effect of insulin. In normal metabolism, insulin and glucagon work to keep blood glucose levels constant.
With type 2 diabetes the glucagon system can lose its precision too, signaling for a release of glucose from your liver even when blood glucose levels are normal or already high. That premature release of stored glucose results in high blood glucose levels not related to food. But, even though we don’t often talk very much about this aspect of type 2 diabetes, it is so significant that the most common medication for type 2 diabetes – metformin – works to manage blood glucose levelsprimarily by reducing the release of stored glucose from your liver.
Were the financial costs of type 2 diabetes surprising to you?