Which hormone plays a significant role in the regulation of blood glucose levels?

Insulin is a key hormone in the regulation of blood glucose levels. It is produced by the pancreas and acts primarily to lower blood sugar levels by facilitating the uptake of glucose into cells, particularly muscle and adipose (fat) tissue. When blood glucose levels rise after eating, insulin is released to help cells absorb glucose for energy or to store it as glycogen in the liver and muscles for later use. This process is crucial for maintaining homeostasis and ensuring that blood glucose levels remain within a normal range.

The other hormones mentioned affect metabolism and stress responses but play different roles concerning glucose regulation. Adrenaline increases blood sugar levels by stimulating glycogenolysis (the breakdown of glycogen to glucose) during the fight or flight response. Thyroxine primarily regulates metabolism and energy levels, while cortisol is involved in stress response and can also increase blood glucose levels by promoting gluconeogenesis in the liver. However, neither adrenaline, thyroxine, nor cortisol directly regulate blood glucose levels in the same way that insulin does.