Integrated metabolic regulation during acute rest states in man, similarity to fasting: a biochemical hypothesis

Many physiologic changes have been described in association with acute rest states in man. In particular, among metabolic changes, there occur marked decrease of forearm respiratory quotient, increased forearm venous beta-hydroxybutyric acid, decreased forearm lactate generation, and decreased red cell glycolysis. One primary hypothesis of metabolic control that is capable of interrelating these metabolic changes is that in peripheral tissue there is an overall shift of substrate away from glucose toward increased fatty acid beta-oxidation, such as occurs in fasting. Since regulation of lipid and carbohydrate metabolism is central to several major disorders, such a putative shift of metabolic control and its mechanism may have many basic and clinical implications, including, especially, slowing of biological aging.