Final answer:
When fasting, insulin production decreases while glucagon is released to elevate blood glucose levels by promoting the breakdown of glycogen in the liver. These hormones work in a negative feedback loop to maintain stable blood sugar levels, which is essential for normal bodily function.
Step-by-step explanation:
When we have not eaten in a while, the levels of insulin and glucagon in the body undergo significant changes. After eating, insulin is released by the pancreas in response to high blood glucose levels to help cells absorb glucose, which is then used for energy or stored for later use. However, during periods of fasting, insulin production decreases because there is less glucose entering the bloodstream. Instead, the glucagon hormone is released by the pancreatic alpha cells when blood glucose levels fall. Glucagon's role is to raise blood sugar levels by signaling the liver to break down glycogen into glucose and release it back into the bloodstream, ensuring that the body's cells have sufficient energy to function. These processes are part of a complex feedback system aimed at maintaining blood sugar levels within a narrow, healthy range. For individuals with diabetes mellitus, this system can be disrupted, leading to abnormal insulin and glucagon levels. This can result from a variety of factors such as defective insulin receptors or antibodies to insulin, affecting how an individual responds to insulin.