RELATIONSHIP BETWEEN GLUCONEOGENESIS AND PHOSPHOENERGETICS IN RAT-LIVER ASSESSED BY IN-VIVO C-13 AND P-31 NMR-SPECTROSCOPY

The relationship between the phosphoenergetic state and gluconeogenesi s in the liver after ischemic damage was investigated using living rat s, The ATP level was determined with in vivo P-31 nuclear magnetic res onance spectroscopy, and gluconeogenesis was evaluated with in vivo C- 31 NMR spectroscopy using L-[3-C-13]alanine as a tracer, These two mea surements were alternated repeatedly, The rats were divided into three groups: without ischemia (group A); with 10 min ischemia (group B); a nd with 30 min ischemia (group C), ATP was depleted to 20% of the prei schemic state after 10 min ischemia and this level was maintained duri ng 30 min ischemia, After reperfusion, the ATP level was partially res tored, but the recovery was smaller in group C, Infusion of [3-C-13]al anine was started immediately after the reperfusion, In vivo C-13 NMR disclosed changes in the alanine C3, glutamine/glutamate C2 and C3, gl ucose C1-6, and glycogen C1 signals in the liver, After 60 min infusio n of [3-C-13]alanine, the ATP level correlated negatively with the sig nal intensity of alanine (r=-0,663,p=0.008) and positively with those of glucose and glyogen (r=0,586,p=0.023, and r=0,643,p=0.011, respecti vely), These results suggest that the ATP level participates in glucon eogenesis and glycogenesis in the liver Such multinuclear in vivo NMR observations might uncover new aspects of the metabolic function of th e liver in the in vivo state. (C) 1997 by John Wiley & Sons, Ltd.