A COMPARISON OF ATP RECOVERY OR PHOSPHOMONOESTER INORGANIC-PHOSPHATE RATIO TO ASSESS METABOLIC-ACTIVITY IN LIVER AT HYPOTHERMIA - A P-31 NMR-STUDY

We have used P-31 MRS to evaluate liver metabolic activity at hypother mia using two indices which have been previously proposed, the ratio o f beta-ATP to total phosphorus signal, and the ratio of phosphomonoest ers to in organic phosphate (PME/P-i). Porcine livers were studied dur ing hypothermic reperfusion after cold hypoxia, and during a second pe riod of hypoxia. Signals for ATP changed by an order of magnitude, bot h rapidly and predictably for periods of aerobic or anaerobic metaboli sm, but the PME/P-i ratio changed by only a small amount, and in a unp redictable fashion. Although the PME/P-i ratios may be easier to measu re because these peaks are easy to define in whole-organ spectra, they appear to be less sensitive indices of resumption of organ metabolism , at least in the early post-hypoxic state.