Calculation of substrate oxidation rates in vivo from gaseous exchange.

  title={Calculation of substrate oxidation rates in vivo from gaseous exchange.},
  author={K. N. Frayn},
  journal={Journal of applied physiology: respiratory, environmental and exercise physiology},
  volume={55 2},
  • K. Frayn
  • Published 1 August 1983
  • Biology
  • Journal of applied physiology: respiratory, environmental and exercise physiology
This paper reviews the assumptions involved in calculating rates of carbohydrate and fat oxidation from measurements of O2 consumption, CO2 production, and urinary nitrogen excretion. It is shown that erroneous results are obtained in the presence of metabolic processes such as lipogenesis and gluconeogenesis. The apparent rates calculated under these conditions can, however, be interpreted as net rates of "utilization." Thus the apparent rate of carbohydrate oxidation is the sum of the rates… 

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