FIG. 1.

Preischemia ³¹P (a) and ¹H (b) spectra of the HFBR C6 cell culture. Spectra were obtained at approximately 250 h of growth after inoculation. Labels in the ³¹P spectrum are: GPC, glycerophosphorylcholine; NTP, nucleoside triphosphates; P_i, inorganic phosphate; and PME, phosphomonoesters. The ¹H spectrum was obtained before (black line) and after (gray line) the infusion of 5 mM Gd-DTPA into the media, which results in a splitting between intracellular (0 Hz) and extracellular (+185, +135 Hz) water components. The ¹H spectrum obtained before Gd-DTPA was scaled down by a factor of eight for plotting.