Final answer:
The transition from feasting to fasting and vice versa is primarily controlled by the hormones insulin and glucagon. Insulin lowers high blood glucose levels, while glucagon raises them when they are too low, thus maintaining blood glucose homeostasis.
Step-by-step explanation:
The hormones most important for controlling the transition between feasting and fasting are insulin and glucagon. These two hormones play crucial roles in maintaining blood glucose homeostasis. Insulin, secreted by the pancreatic beta cells when blood glucose levels are high, promotes the uptake of glucose into cells and its conversion into glycogen or fats. It also inhibits glucose production by the liver. Conversely, when blood glucose levels are low, glucagon is secreted by alpha cells in the pancreas, stimulating the breakdown of glycogen back into glucose.
These hormonal regulation mechanisms ensure that the body's cells receive a steady supply of glucose for cellular respiration and energy production. The homeostatic control of blood glucose is a finely tuned system that balances insulin and glucagon secretion to maintain blood glucose levels within the normal range, allowing for effective metabolic regulation during times of food intake and fasting.