HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bender, D. Articles by Keiding, S. Search for Related Content PubMed PubMed Citation Articles by Bender, D. Articles by Keiding, S.

Metabolites of ¹⁸F-FDG and 3-O-¹¹C-Methylglucose in Pig Liver

PET Center and Department of Medicine V, Aarhus University Hospital, Aarhus; and Institute of Experimental Clinical Research, University of Aarhus, Aarhus, Denmark

PET uses ¹⁸F-FDG widely to estimate glucose metabolism in vivo. Dynamic PET data are evaluated by kinetic models of the metabolic pathways. Knowledge of the metabolites of FDG is of critical importance for the interpretation of kinetic PET studies. The purpose of this study was to determine the metabolic pathways of FDG and 3-O-¹¹C-methylglucose (MG) in liver tissue in vivo. It is usually assumed that MG is not metabolized and FDG is converted to ¹⁸F-FDG-6-phosphate (FDG-6-P). Methods: The study was performed on 6 anesthetized 40-kg pigs that were given the 2 tracers intravenously. The content of metabolites was determined in successive liver tissue biopsies. Freeze-clamped liver tissue samples were subjected to extraction by acetonitrile at -5°C to -10°C, and extracts were analyzed by radio–high-performance liquid chromatography (radio-HPLC). The findings were identified by means of radio-HLPC measurements of the products of in vitro enzymatic reactions. Results: The applied extraction technique provided almost quantitative recovery of the radioactivity from tissue. After MG injection, only MG was detectable in the liver tissue; no labeled metabolites were found. After FDG injection, 2 metabolites were identified, FDG-6-P and 2-¹⁸F-fluoro-2-deoxy-6-phosphogluconate (FD-6-PG1). The tissue content of FDG increased rapidly, and, after 5 min, only FDG was identified; hereafter, the fraction of FDG decreased to approximately 40% of the tissue radioactivity after 180 min. After 20 min, FDG-6-P was found in each of the pigs and it increased throughout the measurement period of 180 min, with a somewhat slower rise at late time points. FD-6-PG1 began to appear in the liver tissue after 45 min and increased throughout the 180-min experiment, with the increase somewhat slower than that of FDG-6-P. After 180 min, approximately 40% of the metabolites was attributed to FD-6-PG1. The content of other metabolites was <2%, even after 180 min. Conclusion: After the FDG injection, not only FDG-6-P but also FD-6-PG1 were formed in the liver. Any possible incorporation of FDG into glycogen was of minor importance.

Key Words: PET • metabolism • radiochemistry

This article has been cited by other articles:

				M. Sorensen, O. L. Munk, F. V. Mortensen, A. K. Olsen, D. Bender, L. Bass, and S. Keiding Hepatic uptake and metabolism of galactose can be quantified in vivo by 2-[18F]fluoro-2-deoxygalactose positron emission tomography Am J Physiol Gastrointest Liver Physiol, July 1, 2008; 295(1): G27 - G36. [Abstract] [Full Text] [PDF]

				A. Bertoldo, J. Price, C. Mathis, S. Mason, D. Holt, C. Kelley, C. Cobelli, and D. E. Kelley Quantitative Assessment of Glucose Transport in Human Skeletal Muscle: Dynamic Positron Emission Tomography Imaging of [O-Methyl-11C]3-O-Methyl-D-Glucose J. Clin. Endocrinol. Metab., March 1, 2005; 90(3): 1752 - 1759. [Abstract] [Full Text] [PDF]

				P. Iozzo, F. Geisler, V. Oikonen, M. Maki, T. Takala, O. Solin, E. Ferrannini, J. Knuuti, and P. Nuutila Insulin Stimulates Liver Glucose Uptake in Humans: An 18F-FDG PET Study J. Nucl. Med., May 1, 2003; 44(5): 682 - 689. [Abstract] [Full Text] [PDF]

				K. V. Williams, A. Bertoldo, B. Mattioni, J. C. Price, C. Cobelli, and D. E. Kelley Glucose Transport and Phosphorylation in Skeletal Muscle in Obesity: Insight from a Muscle-Specific Positron Emission Tomography Model J. Clin. Endocrinol. Metab., March 1, 2003; 88(3): 1271 - 1279. [Abstract] [Full Text] [PDF]

				K. Kaarstad, D. Bender, L. Bentzen, O. L. Munk, and S. Keiding Metabolic Fate of 18F-FDG in Mice Bearing Either SCCVII Squamous Cell Carcinoma or C3H Mammary Carcinoma J. Nucl. Med., July 1, 2002; 43(7): 940 - 947. [Abstract] [Full Text] [PDF]

				L. I. Wiebe FDG Metabolism: Quaecumque Sunt Vera ... J. Nucl. Med., November 1, 2001; 42(11): 1679 - 1681. [Full Text] [PDF]