In vivo 13CNMR spectroscopy of glucose metabolism of RIF-1 tumors.

Abstract

An efficient method for measuring in vivo 13C NMR spectra of tumors has been developed and employed to monitor glucose metabolism in radiation-induced fibrosarcomas (RIF-1) subcutaneously implanted in C3H/HeN mice. [1-13C]Glucose was injected directly into the tumors at a dose of 1 g/kg body wt. Spectra were obtained with a Bruker AM 360-WB spectrometer (8.4 T/8.9 cm bore) employing a homebuilt probe equipped with a four-turn solenoidal coil (1.5 cm outer diameter) for detection of 13C signals and a Helmholtz coil (two 3-cm turns separated by a 3-cm gap, oriented orthogonally to the 13C coil) for 1H decoupling. In addition to the natural abundance 13C resonances of the tumors, signals were detected from the alpha- and beta-anomers of labeled glucose. Within 15 min following injection of labeled glucose [3-13C]lactate and [3-13C]alanine were detected. Lactate labeling approached steady state levels within about 50 min after glucose injection: in contrast, alanine labeling increased continuously over the duration of the experiment (70 min). Sixty minutes after glucose injection, the ratio of the intensity of [3-13C]lactate to the principal lipid methylene resonance (30 ppm from external tetramethylsilane), which served as an internal intensity reference, was correlated with tumor size, whereas the corresponding ratio of the [3-13C]alanine resonance was not. Labeling of glutamate was below the level of detection in the in vivo spectra; however, labeling of C4-glutamate at a level approximately 50-fold lower than the level of [3-13C]lactate was detected in perchloric acid extracts. Incorporation of 13C label into C2- and C3-glutamate and C2-lactate was also observed.

• Authors: I Constantinidis, J C Chatham, J P Wehrle, J D Glickson
• Journal: Magnetic resonance in medicine (Magn Reson Med) Vol. 20 Issue 1 Pg. 17-26 (Jul 1991) ISSN: 0740-3194 [Print] United States
• PMID: 1943658 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Lactates
• Carbon
• Glucose

Topics

• Animals
• Carbon
• Female
• Fibrosarcoma (metabolism, pathology)
• Glucose (administration & dosage, metabolism)
• Injections, Intralesional
• Injections, Intraperitoneal
• Injections, Intravenous
• Lactates (metabolism)
• Magnetic Resonance Spectroscopy (instrumentation, methods)
• Mice
• Mice, Inbred C3H
• Mice, Inbred Strains
• Neoplasm Transplantation
• Neoplasms, Radiation-Induced (metabolism, pathology)
• Skin Neoplasms (metabolism, pathology)
• Time Factors