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Role of oxygen vs. glucose in energy metabolism in a mammary carcinoma perfused ex vivo: direct measurement by 31P NMR
- Source :
- Proceedings of the National Academy of Sciences. 90:2646-2650
- Publication Year :
- 1993
- Publisher :
- Proceedings of the National Academy of Sciences, 1993.
-
Abstract
- The role of glycolysis vs. respiration in tumor energy metabolism has been studied, to date, primarily in vitro by using single cells, multicellular spheroids, or tissue slices. With the advent of in vivo NMR spectroscopy, several investigators have shown that tumor energy status depends on its blood flow. Since manipulation of blood flow alters both oxygen and glucose delivery to a solid tumor, these studies have not been able to separate the relative contribution of oxygen vs. glucose in energy metabolism in vivo. In the present study, we have overcome this problem by combining two methods: the tissue-isolated R3230AC mammary adenocarcinoma perfused ex vivo and 31P NMR spectroscopy. The isolated tumor permits one to control the perfusion pressure as well as the metabolite concentrations in the perfusate. NMR spectroscopy permits one to measure the ratio of nucleoside triphosphate to inorganic phosphate (NTP/Pi) and pH. Our results show that (i) the NTP/Pi ratio ex vivo is similar to that observed in vivo prior to surgery, (ii) the NTP/Pi ratio is insensitive to flow changes at high flow rates but is proportional to flow rate at flows comparable to those found in vivo, (iii) the NTP/Pi ratio of these tumors is resistant to hypoxia and is not maintained when glucose is removed or replaced with glutamine, and (iv) although both O2 and glucose are consumed by these tumors, the effect of perfusate flow rate appears to be mediated largely through glucose delivery. The current approach not only provides information about the role of glycolysis vs. respiration in a rodent tumor but also is general and versatile enough to provide similar data in human tumors perfused ex vivo.
- Subjects :
- Magnetic Resonance Spectroscopy
Time Factors
Cellular respiration
Metabolite
Adenocarcinoma
Carbohydrate metabolism
Biology
Phosphates
chemistry.chemical_compound
Oxygen Consumption
In vivo
Respiration
Animals
Glycolysis
Hypoxia
Multidisciplinary
Mammary Neoplasms, Experimental
Phosphorus
Hydrogen-Ion Concentration
Rats, Inbred F344
Rats
Oxygen
Kinetics
Glucose
chemistry
Biochemistry
Lactates
Female
Energy Metabolism
Perfusion
Ex vivo
Research Article
Subjects
Details
- ISSN :
- 10916490 and 00278424
- Volume :
- 90
- Database :
- OpenAIRE
- Journal :
- Proceedings of the National Academy of Sciences
- Accession number :
- edsair.doi.dedup.....87aa85b490e4b8ff8e9eda1db6d02efe