title: Effects of pentobarbital anesthesia on the energy metabolism of murine tumors studied by in vivo 31P nuclear magnetic resonance spectroscopy.
abstract: The effects of pentobarbital anesthesia on the energy metabolism of FSaII and MCaIV foot tumors in mice were studied by 31P MRS. Using an 8.5 T spectrometer, in vivo spectra were obtained in 15 animals before and after pentobarbital anesthesia (0.05 mg/g ip). The average phosphocreatine/inorganic phosphate ratios (PCr/Pi) with and without pentobarbital were similar for both tumor histologies. Effects on individual tumors, however, were greater than 20% in 9/15 animals and greater than 50% in 6/15 animals. Pentobarbital anesthesia increased the variability of tumor intracellular pH, and the phosphomonoester/nucleotide triphosphate (PME/NTP) and nucleotide triphosphate/inorganic phosphate ratios (NTP/Pi). When examining the average in a cohort, pentobarbital anesthesia had no significant effect on the PCr/Pi, PME/NTP, NTP/Pi ratios or the pH. However, approximately equal to 50% of individual tumors do have significant changes in these parameters. The anesthesia-induced variability of tumor energy metabolism may explain the decrease in TCD50 observed in previous studies using multifraction radiation.
authors.affiliation: Department of Radiation Medicine, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
authors.forename: P
authors.initials: P
authors.lastname: Okunieff
authors.forename: E
authors.initials: E
authors.lastname: Rummeny
authors.forename: P
authors.initials: P
authors.lastname: Vaupel
authors.forename: S
authors.initials: S
authors.lastname: Skates
authors.forename: C
authors.initials: C
authors.lastname: Willett
authors.forename: L J
authors.initials: LJ
authors.lastname: Neuringer
authors.forename: H D
authors.initials: HD
authors.lastname: Suit
mesh_terms: D000758:Anesthesia / Q000379:methods; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D004307:Dose-Response Relationship, Radiation; D004734:Energy Metabolism / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008809:Mice, Inbred C3H; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000378:metabolism* / Q000473:pathology / Q000532:radiotherapy; D009711:Nucleotides / Q000032:analysis; D010424:Pentobarbital / Q000494:pharmacology*; D010710:Phosphates / Q000032:analysis; D010725:Phosphocreatine / Q000032:analysis; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology
chemical_list: D009711:Nucleotides; D010710:Phosphates; D011838:Radiation-Sensitizing Agents; D010725:Phosphocreatine; D010424:Pentobarbital