[Plasma glutathione of patients with coronary heart disease measured by fluorospectrophotometer].

The standard samples of reduction form glutathione (GSH) and oxidization form glutathione (GSSG) were scanned with full-wavelength range to determine the excitation wavelength lambda(ex) 334.4 nm, the emission wavelength lambda(em) 424 nm, and the spectral bandwidth 5 nm respectively. Phosphate buffer saline (PBS) of pH 8. 3 served as buffer solution. GSH was incubated for 30 min with 100 microL o-phthaldehyde (OPA) of 10 mmol x L(-1) methyl alcohol solution for derivatization, and then fluorescence intensities were measured. With standard glutathione concentration being independent variable and fluorescence intensity being dependent variable, the linear equations for GSH and GSSG were deduced: Y(GSH) = 6.9 + 8.6X (r2 = 0.994) and Y(GSSG) = 6.2 + 17.2X (r2 = 0.999). Standard curves were done hereby. The plasma glutathione of three groups was then measured, and GSH/ GSSG redox potential was calculated according to Nernst equation. The results indicated that, from normal control group to prophase coronary heart disease group, then to coronary heart disease group, the GSH and GSH/GSSG ratio gradually reduced, GSSG and GSH/GSSG redox potential gradually increased (more positive) (all P < 0.05), and the redox potential shifted to oxidization direction along with the development of coronary heart disease. This fluorospectrophotometry method showed simple operation, and fine precision and accuracy.