Blood and plasma glutathione measured in healthy subjects by HPLC: relation to sex, aging, biological variables, and life habits

We report an HPLC method for measuring the concentrations of reduced (GSH) and total (GSHt) free glutathione in human plasma and whole blood. The chromatographic step was coupled with a postcolumn derivatization reaction and fluorometric detection. The linear range was 0.81-13.02 mumol/L, and the detection limit was 0.13 mumol/L. In healthy adults (ages 18-73 years), mean concentrations were 941 +/- 155 mumol/L for GSHt and 849 +/- 63 mumol/L for GSH in blood (107 men, 94 women), and 3.39 +/- 1.04 mumol/L for GSH in plasma (66 men, 58 women). Blood GSHt but not GSH was significantly lower in children (32 boys, 32 girls: 872 +/- 157 mumol/L) than in adults. Blood GSHt and GSH appeared to be correlated positively with the number of cigarettes smoked per day and the regular practice of physical exercise, and negatively with alcohol abstinence. We observed positive correlations between blood GSHt and cholesterol and calcium concentrations, and between blood GSH and cholesterol concentration.