title: [1,2-13C2]-D-glucose profiles of the serum, liver, pancreas, and DMBA-induced pancreatic tumors of rats.
abstract: OBJECTIVE
  In vitro stable isotope glucose tracer studies indicate that undifferentiated cells of the pancreas use glucose primarily through the nonoxidative reactions of the pentose cycle for nucleic acid ribose synthesis, whereas normal or less transformed cells primarily use the oxidative branch of the cycle.
  
  
  METHODS
  The pancreatic heads of 4 groups (5/group) of male rats were implanted with time-release pellets designed to deliver placebo or 7,12-dimethylbenzanthracene (DMBA) at 11, 33, or 56 mg/d. Four weeks after pancreatic exposure to DMBA, [1,2-C2]-D-glucose tracer (1 g/kg) was injected intraperitoneally followed by sera collection at 1 and 2 hours and harvest of tumors, adjacent pancreatic tissue, and sera at 3 hours.
  
  
  RESULTS
  Tumors (2-9 mm) were found across DMBA groups, with the largest in the high-dose group (> or =5 mm). Selective monitoring by gas chromatography-mass spectrometry of the doubly-labeled [1,2-C2]-D-ribose of RNA, which requires nonoxidative synthesis in the pentose cycle, showed a 2.8-, 2.9-, and 5.7-fold increase in pancreatic tumors. Liver and adjacent pancreas preferentially produced [1-C1]-D-ribose through the oxidative reactions of the cycle. Tumor-bearing animals also cleared and recycled tracer glucose at a faster rate.
  
  
  CONCLUSIONS
  Simultaneous selective positional ion monitoring of C-labeled metabolites and their mass isotopomers in tissues and blood opens new avenues for the early detection and response to therapy testing of pancreatic cancer using GC-MS and/or magnetic resonance imaging-based methods. This study emphasizes the benefits of stable isotope-based dynamic metabolic profiling, when applied in vivo, and the several advantages it offers to positron emission tomography.
authors.affiliation: SIDMAP, LLC, and Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA 90502, USA. boros@labiomed.org
authors.forename: László G
authors.initials: LG
authors.lastname: Boros
authors.forename: Megan R
authors.initials: MR
authors.lastname: Lerner
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Morgan
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Taylor
authors.forename: Brenda J
authors.initials: BJ
authors.lastname: Smith
authors.forename: Russell G
authors.initials: RG
authors.lastname: Postier
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Brackett
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism*; D002247:Carbon Isotopes; D005947:Glucose / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008297:Male; D010179:Pancreas / Q000378:metabolism*; D010190:Pancreatic Neoplasms / Q000139:chemically induced / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001786:Blood Glucose; D002247:Carbon Isotopes; D015127:9,10-Dimethyl-1,2-benzanthracene; D012313:RNA; D005947:Glucose