The Liver is a multifunction organ part of which forms a storage for surplus glucose within the body. When the B/G level gets too low the Liver is called upon to discharge it's temporary store of reserve glucose back into the bloodstream to help maintain the body's supply of background blood glucose levels. It is also responsible for the early morning BOOST that occurs at daybreak so as to give the body a good start to the day (this dates way back to stone age times)
Sometimes the Liver will run out of the available energy boost, or sometime a sudden demand for glucose energy by the body cannot be met, and the B/G levels drop too quickly to below a safe level resulting in a Hypo. and to ensure that sufficient Glucose is available in this potentially dangerous situation it then becomes essential to get some into the individuals bloodstream ASAP.
Some diabetic medications are also known to lower B/G to below a safe level (Glickazide being one of them) and even Type 2's on diet alone can experience Hypo's. In my own research at one stage I experienced them twice though at this time my diabetes was controlled by diet alone, and on both occasions it was a particularly hot summer's day, I had eaten a high GL meal and been rushing around town. I suspect the Hypo's that I induced was the combination of becoming de-hydrated and having eaten high GL foods alone before heavy exercise which produce a type of hypo generally known a 'Reactive Hypoglycaema). A rare occurance but indeed possible as I eventually found out and had confirmed by a medical expert in diabetes.
Hope this information is of some benefit and gives you a few answers.