Modulation of paraoxonase 1 and 3 expression after moderate exercise training in the rat.

PONs are a small family of antioxidant enzymes, whose antiatherogenic activity is well known. Aim of the present study was the evaluation of the effects of moderate aerobic training on their expression, using a rat model. In order to discriminate between PON1 and PON3 enzymatic activity, we took advantage of some differences in their substrate preferences. PON1 and PON3 enzymatic activities and their protein level were analyzed in plasma and in liver microsomes, their mRNA level in the liver. Exercise training did not affect PON1 expression or enzymatic activity, but increased PON3 mRNA, protein levels and enzymatic activity. Training also induced variations in plasma membrane composition, including an increase in polyunsaturated and a decrease in mono- and di-unsaturated fatty acids. On the other hand, acute exercise inhibited PON activities, while increasing PON3 protein content in liver microsomes and reversing the relative composition in mono- di- and poly-unsaturated fatty acids, thus suggesting that physical stress, by altering membrane composition, may impair PON release from liver membranes. In conclusion, we documented for the first time the presence of PON3 in rat serum, and, notably, found that the upregulation of PON3 rather than PON1 appears to be associated with physical training