NON‐SHIVERING THERMOGENESIS AND ITS THERMOREGULATORY SIGNIFICANCE

Summary 1. Non‐shivering thermogenesis (NST) is a heat‐production mechanism participating in the chemical thermoregulation of mammals. 2. NST is additional to shivering and takes place at temperatures close to the thermoneutral zone. 3. NST occurs in newborn mammals and in those that hibernate. In some adult mammals it can be induced by adaptation to cold. 4. In small mammals NST produces approximately the same amount of heat as shivering. It becomes less important with increasing body weight of the animals. 5. NST is regulated by the hypothalamus and it is based predominantly on the calorigenic action of noradrenaline released from sympathetic nerve‐endings. Participation of other calorigenic substances and of the specific dynamic action of food cannot be excluded. 6. NST is localized mainly in skeletal muscles and in brown adipose tissue. Small amounts of NST may come from liver, intestine, heart and brain. 7. The biochemical basis of the calorigenic action of noradrenaline has not yet been fully elucidated.