Final answer:
Glucose levels decrease after 8-10 hours of not eating as the body starts to use up stored glycogen for energy. The hormone glucagon is released to help maintain normal blood glucose levels.
Step-by-step explanation:
After 8-10 hours of not eating, glucose levels in the blood decrease. During the postabsorptive state or fasting state, the body relies on stored glycogen. As glycogen stores are depleted, glucose levels begin to fall. In response to this depletion, the pancreas releases the hormone glucagon, which acts on liver cells to stimulate the breakdown of glycogen into glucose, trying to maintain blood glucose levels within the normal range. However, if fasting continues beyond this period and glycogen stores are exhausted, blood glucose levels can drop significantly below normal.
Therefore, the correct answer to the question regarding what happens to glucose levels after 8-10 hours of no food is: 1) They decrease.