Pasteur effect

The Pasteur effect is the normal response of cells to restrain glycolysis in the presence of adequate oxygen 2. This control system is characterized by the suppression of lactic acid production from glucose when oxygen is available, allowing the cell to consume its product oxidatively 1. The Pasteur effect is a fundamental aspect of cellular metabolism, and its failure is associated with cancer, where glycolysis becomes relatively independent of respiration and leads to inefficient sugar consumption 5.

The Pasteur effect was first described by Louis Pasteur, who showed that fermentation was an internal process of living organisms that occurred in the absence of oxygen 1. However, his work was met with skepticism by mechanists who considered it "vitalism" and unscientific. It wasn't until later that the Pasteur effect was recognized as a normal control system that allows cells to adapt to changing oxygen levels 2.

In the presence of high estrogen and unsaturated fatty acids, the body's normal response to oxygen is impaired, leading to the production of lactic acid and the inability to use energy oxidatively 6. This is in contrast to the normal Pasteur effect, where oxygen turns off lactic acid production. The failure of the Pasteur effect is also associated with cancer, where glucose is consumed too rapidly in the presence of oxygen, leading to the production of excess lactate 8.

The Pasteur effect is closely related to the Crabtree effect, which is the suppression of respiration by glycolysis 5. However, unlike the Pasteur effect, the Crabtree effect tends to lower cellular energy and adaptability. The failure of the Pasteur effect has significant implications for our understanding of cancer metabolism and the development of new treatments 4.