Which hormone is released from the pancreas and lowers blood glucose levels?

Insulin is the hormone released from the pancreas that plays a crucial role in lowering blood glucose levels. It is produced by the beta cells of the islets of Langerhans in the pancreas. When blood sugar levels rise after eating, insulin is secreted into the bloodstream. Its primary function is to facilitate the uptake of glucose by cells, particularly in muscle and fat tissues, thus reducing the concentration of glucose in the bloodstream.

Moreover, insulin promotes the conversion of glucose to glycogen in the liver, a process known as glycogenesis, which further helps in managing blood sugar levels. By increasing glucose uptake and storage, insulin effectively plays a vital role in maintaining homeostasis and regulating energy balance in the body.

Other hormones mentioned do not perform the same function. For instance, glucagon, which is secreted by alpha cells in the pancreas, works to raise blood glucose levels, counteracting the effects of insulin. Melatonin is associated with regulating sleep cycles, while calcitonin is involved in calcium homeostasis, indicating the specificity of insulin's role in glucose metabolism.