How does the liver make and store glycogen according to Claude Bernard’s research?

Claude Bernard’s research fundamentally changed the understanding of metabolism by identifying the glycogenic function of the liver. In 1856, he discovered glycogen, a white, starchy substance that the body synthesizes from sugar.12

Bernard demonstrated that the liver acts as a storage reserve for carbohydrates, building up these complex molecules from simpler ones. This process allows the body to maintain a constant level of sugar in the blood by breaking down stored glycogen into sugar whenever the body requires it.2

This discovery was significant because it proved that the digestive system does not merely break down complex molecules; it also possesses the capacity to build them up. By showing that the liver regulates blood sugar levels to maintain a stable internal environment, Bernard provided a foundational example of homeostasis.21