Effect of Potassium-Rich Medium, of Glucose and of Transfer of Tissue on Oxygen Consumption by Rat Diaphragm

Abstract

Oxygen consumption of the rat diaphragm is the same during incubation in each of these media: Krebs-Ringer-phosphate, calcium- and magnesium-free Krebs-Ringer-phosphate, a potassium-rich medium and a potassium-rich medium plus glucose, providing incubation is not interrupted by transfer of diaphragm to fresh media. When the diaphragm is manipulated (sham transfer) after an initial incubation there is a reduction of 10–15% in oxygen consumption. When, after an initial incubation, the diaphragm is transferred to fresh media there is a further decrease in oxygen consumption which is greatest in glucose-free media and least in the glucose-containing medium. When, after transfer and reincubation in a fresh flask, the diaphragm is returned to its initial flask and reincubated there is relative restoration of its oxygen consumption. These observations suggest that oxidizable endogenous substrates diffuse from the diaphragm during incubation.