Figure 4. Typical spectra of livers isolated from NOM- and vehicle-treated mice.

The upper spectra were obtained with livers isolated after i.p. injections of NOM (A) or vehicle (B). The liver was homogenized with a fresh (MGD)₂–Fe²⁺ complex, and was frozen 30 min later. The thin spectra (C and D) were recorded with mixtures of (MGD)₂–Fe²⁺ and NOM (1 or 10 μM), diluted twice in 0.1 M phosphate buffer, pH 7.5, as for tissue extracts. Samples were frozen in 5-mm quartz tubes in liquid nitrogen, and spectra were recorded on a Magnettech EPR spectrometer. Instrument settings are indicated in the Materials and methods section.