Which hormone opposes the effects of insulin?

The correct choice is glucagon because it plays a critical role in regulating blood glucose levels by opposing the effects of insulin. Insulin is released by the pancreas in response to high blood glucose levels and functions to lower blood sugar by facilitating the uptake of glucose into cells and promoting the storage of glucose in the liver as glycogen.

Glucagon, on the other hand, is released when blood glucose levels are low. It prompts the liver to convert stored glycogen back into glucose, which is then released into the bloodstream, thereby increasing blood sugar levels. This balance between insulin and glucagon maintains homeostasis in the body's glucose levels, ensuring that there is enough energy available for cellular processes.

While hormones like adrenaline (epinephrine), cortisol, and somatostatin have roles in metabolism and can affect blood sugar levels as well, their primary functions are different. Adrenaline prepares the body for the "fight or flight" response, increasing glucose availability but not directly counteracting insulin. Cortisol is a stress hormone that can also increase glucose levels but does so over a longer time frame and is involved in stress response rather than immediate glucose regulation. Somatostatin inhibits the release of both insulin and glucagon, but it doesn't directly serve to