What effect does insulin have on blood glucose levels?

Insulin plays a crucial role in the regulation of blood glucose levels. It is a hormone produced by the pancreas in response to elevated blood glucose levels, usually after meals. The primary effect of insulin is to decrease blood glucose levels by facilitating the uptake of glucose into cells, particularly in muscle and adipose (fat) tissue.

When insulin is released into the bloodstream, it binds to insulin receptors on the surface of cells, triggering a cascade of events that allows glucose transporters to help glucose enter the cells. This not only reduces the concentration of glucose in the bloodstream but also enables cells to utilize glucose for energy or store it as glycogen in the liver and muscle tissues for future use.

In individuals with insulin resistance or diabetes, this mechanism may be impaired, leading to elevated blood glucose levels. Hence, the correct answer highlights the essential role of insulin in lowering and managing blood glucose, aligning with its primary physiological function.