Table 3. Free SH-groups as a measure for glutathione in MCF-7 and TamR cells as determined by electron spin resonance spectroscopy.

Cells / treatment	Free SH groups pmol/µg protein
MCF-7 control	23.9±1.8
MCF-7 glyoxal	18.8±2.4
MCF-7 methylglyoxal	18.1±2.4
TamR control	13.6±2.2 *
TamR glyoxal	4.6±2.5 a
TamR methylglyoxal	6.3±1.7 b

Cells were grown in RPMI / FCS medium to about 70% confluence before aldehydes were added at 1 mM concentration for 1 h. Experiment was performed three times with duplicates for each treatment. Average and standard error are given. Statistical significance was determined by one way ANOVA after normal distribution was proven by Kolmogorov-Smirnov test.

*: significant to MCF-7 control; a: p = 0.06 to TamR control; b: p = 0.078 to TamR control.