Which hormone is primarily involved in glucose regulation?

Insulin is the primary hormone responsible for regulating glucose levels in the bloodstream. It is produced by the pancreas in response to high blood glucose levels, such as after eating a meal. Insulin facilitates the uptake of glucose into cells, particularly muscle and fat cells, allowing the body to use glucose as an energy source or store it for future use.

In addition to promoting cellular uptake of glucose, insulin also inhibits hepatic glucose production, thereby helping to lower blood sugar levels and maintain homeostasis. Without adequate insulin, as seen in conditions like diabetes mellitus, glucose accumulates in the blood, leading to potential health complications.

While glucagon, cortisol, and thyroxine play roles in metabolism and energy regulation, they do not have the same direct impact on glucose uptake and blood sugar control as insulin does. Glucagon acts to raise blood sugar levels by promoting gluconeogenesis and glycogenolysis in the liver, cortisol influences glucose metabolism during stress, and thyroxine regulates overall metabolism including the rate at which cells utilize glucose. However, insulin remains the central hormone in the immediate regulation of blood glucose levels.