INVIVO METABOLIC EFFECTS OF HYPERGLYCEMIA IN MURINE RADIATION-INDUCED FIBRO-SARCOMA - A P-31 NMR INVESTIGATION
INVIVO METABOLIC EFFECTS OF HYPERGLYCEMIA IN MURINE RADIATION-INDUCED FIBRO-SARCOMA - A P-31 NMR INVESTIGATION
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DOI:
10.1073/pnas.81.20.6496
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发表时间:
1984-01-01
期刊:
影响因子:
--
通讯作者:
ACKERMAN, JJH
中科院分区:
文献类型:
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作者:
EVELHOCH, JL;SAPARETO, SA;ACKERMAN, JJH
The hyperglycemia-induced in vivo metabolic changes produced in s.c. murine RIF-1 tumors, grown on female C3H/Anf mice, were examined with 31P surface-coil NMR. Serum glucose levels were elevated 4-fold by bolus i.p. injection of 0.3 ml of an aqueous 50% glucose solution. Tumor pH was calculated from the chemical shift of Pi and relative phosphocreatine and ATP concentrations were determined by Simpson''s rule integration of the peak areas. Tumor pH decreased by 0.45 U over 2 h while phosphocreatine concentrations decreased by .apprx. 50% over the same time period (n = 9). Initial tumor pH correlated inversely with the initial peak intensity ratio of Pi:ATP2 (r = -0.77). In a significant number of tumors (n = 4), 2 pH populations were observed. In these tumors, one population was unaffected by hyperglycemia and the other showed a decrease in pH. In the other tumors (n = 5), the pH distribution broadened as the pH decreased. In these tumors, the observed decrease in phosphocreatine concentration correlated with that calculated from the effect of measured tumor pH on the intracellular creatine kinase equilibrium (n = 18, r = 0.91). This correlation and consideration of the Pi distribution in the tumor suggest that the pH measured by 31P NMR is weighted heavily by intracellular pH for the RIF-1 tumor. The presence of 2 distinct tumor pH populations or a broadened pH distribution likely reflects variations in tumor microcellular environmment. Control experiments showed negligible changes in tumor pH and high energy phosphate concentrations after bolus i.p. injection of 0.3 ml of isotonic saline. Negligible changes in leg muscle pH and high energy phosphate concentrations were observed after glucose injection into mice with or without tumors. Apparently hyperglycemia induced by i.p. glucose injection is effective in lowering the tumor pH of the murine RIF-1 tumor.