The Nobel Prize in Physiology or Medicine 2019

English (pdf)
Swedish (pdf)[1][2][3]

Nobel Assembly logo


The Nobel Assembly at Karolinska Institutet[4]

has today decided to award

the 2019 Nobel Prize in Physiology or Medicine

jointly to

William G. Kaelin Jr., Sir Peter J. Ratcliffe and Gregg L. Semenza

for their discoveries of how cells sense and adapt to oxygen availability


Animals need oxygen for the conversion of food into useful energy. The fundamental importance of oxygen has been understood for centuries, but how cells adapt to changes in levels of oxygen has long been unknown.

William G. Kaelin Jr., Sir Peter J. Ratcliffe and Gregg L. Semenza discovered how cells can sense and adapt to changing oxygen availability. They identified molecular machinery that regulates the activity of genes in response to varying levels of oxygen.

The seminal discoveries by this year’s Nobel Laureates revealed the mechanism for one of life’s most essential adaptive processes. They established the basis for our understanding of how oxygen levels affect cellular metabolism and physiological function. Their discoveries have also paved the way for promising new strategies to fight anemia, cancer and many other diseases.

Oxygen at center stage

Oxygen, with the formula O2, makes up about one fifth of Earth’s atmosphere. Oxygen is essential for animal life: it is used by the mitochondria present in virtually all animal cells in order to convert food into useful energy. Otto Warburg[5], the recipient of the 1931 Nobel Prize in Physiology or Medicine, revealed that this conversion is an enzymatic process.

During evolution, mechanisms developed to ensure a sufficient supply of oxygen to tissues and cells. The carotid body, adjacent to large blood vessels on both sides of the neck, contains specialized cells that sense the blood’s oxygen levels. The 1938 Nobel Prize in Physiology or Medicine to Corneille Heymans[6] awarded discoveries showing how blood oxygen sensing via the carotid body controls our respiratory rate by communicating directly with the brain.

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