There are 2 main hormones that can control blood glucose levels : insulin and glucagon.
Both of them are produced in the pancreas.
If the blood glucose level is too high, insulin can help by converting glucose into glycogen, the storage form of carbohydrates.
If the blood glucose is too low, glucagon can covert glycogen back into glucose to increase blood glucose level. Both of these hormones can work together to control blood glucose level in body.