What is the role of insulin in glucose metabolism?

Insulin plays a crucial role in glucose metabolism by helping to regulate blood glucose levels and promoting energy storage. When blood sugar levels rise, such as after eating, insulin is secreted by the pancreas.

One of its primary functions is to decrease blood glucose levels. It facilitates the uptake of glucose into the cells, particularly in muscle and fat tissues, where it is used for energy or converted into glycogen for storage. This process is essential for maintaining homeostasis in glucose levels within the bloodstream.

In addition to lowering blood glucose, insulin also promotes energy storage. It encourages the liver and muscle cells to store glucose as glycogen and stimulates fat cells to convert excess glucose into fatty acids for long-term energy storage. This function is critical during periods of energy surplus, allowing the body to utilize glucose efficiently and store any surplus for future energy needs.

Thus, insulin's dual role in both decreasing blood glucose levels and promoting energy storage is encapsulated in the correct answer, which includes both functions. This illustrates the hormone’s importance not just in glucose regulation, but also in overall metabolic balance.