title: The measurement of radiosensitizer-induced changes in mouse tumor metabolism by 31P magnetic resonance spectroscopy.
abstract: Flunarizine and nicotinamide have previously been shown to increase blood perfusion to experimental mouse tumors and consequently, to increase their sensitivity to X rays. These agents were examined for their ability to alter metabolism, measured by 31P magnetic resonance spectroscopy, in the SCCVII/Ha carcinoma and the KHT sarcoma. Flunarizine at 5 mg/kg I.P. produced a 45% reduction in the ratio of inorganic phosphate to total phosphate (Pi/total) in the SCCVII/Ha tumor but only a 24% reduction in this ratio in the KHT tumor. These effects were seen 45 min after drug administration, and ratios returned to control levels by 90 min. In the SCCVII/Ha tumor, nicotinamide at 1000 mg/kg I.P. reduced Pi/total by 56% from 30 min to at least 2 hr after injection, and the ratio was reduced by 59% in the KHT tumor at 30 min after injection, returning to control levels by 2 hr. For the SCCVII/Ha tumor, the time course for the effects of flunarizine and nicotinamide on the inorganic phosphate ratio coincided with that previously reported for radiosensitization.
authors.affiliation: Magnetic Resonance Laboratory, MRC Radiobiology Unit, Chilton, Didcot, Oxon, U.K.
authors.forename: P J
authors.initials: PJ
authors.lastname: Wood
authors.forename: C J
authors.initials: CJ
authors.lastname: Counsell
authors.forename: J C
authors.initials: JC
authors.lastname: Bremner
authors.forename: M R
authors.initials: MR
authors.lastname: Horsman
authors.forename: G E
authors.initials: GE
authors.lastname: Adams
mesh_terms: D000818:Animals; D002277:Carcinoma / Q000378:metabolism*; D005260:Female; D005444:Flunarizine / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D009536:Niacinamide / Q000494:pharmacology*; D010758:Phosphorus; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D012513:Sarcoma, Experimental / Q000378:metabolism*
chemical_list: D011838:Radiation-Sensitizing Agents; D009536:Niacinamide; D010758:Phosphorus; D005444:Flunarizine