RAPID ATP ASSAYS IN PERFUSED MOUSE-LIVER BY P-31-NMR

31P NMR was used to continuously monitor ATP and inorganic phosphate levels in perfused mouse liver. Under 'optimal' conditions, the time resolution of the technique was approximately 1 min. In the absence of any metabolic perturbations the ATP level remained constant for at least 2 hr and decreased by only approximately 20% in 18 hr. Both ATP and inorganic phosphate levels responded to alterations in the oxygen supply to the liver. The half-time for this response was approximately 1 min, and the response to short periods of hypoxia or ischemia was partially reversible. The addition of insulin caused only a minor decrease in the ATP level but significantly decreased the rate of response of ATP and phosphate levels to hypoxia and ischemia.