Assessment of oxidative stress markers and prostaglandins after chronic training of triathletes.

The present study established the pattern of isoprostanes (IsoPs) and prostaglandins metabolites (PGMs) in urine after triathlon training. Fifteen Caucasian triathletes - 5 women and 10 men - performed 793 and 1603 Objective Load Scales, respectively. The optimization of urine hydrolysis conditions, concerning to the type of buffer, the units of hydrolytic enzyme added, and the pH, allowed precise quantification of these metabolites by UPLC-MS/MS, avoiding the under-estimation of their concentrations that occurred in previous studies. Their rate of conjugation ranged between 36% and 100%. This implies significant importance since it supposes non-detection of some IsoPs and PGMs totally conjugated with glucuronic acid developed by other previous methodologies. Among the 13 compounds analyzed, this assay detected and characterized 4 IsoPs and 3 PGMs in the triathletes' urine. The PGMs tetranor-PGEM and 11β-PGF(2α) and the IsoP 8-iso-PGF(2α), showed lower concentrations after the training program, whereas the PGMs 6-keto-PGF(1α) increased (vascular PGI(2) metabolite). In fact, their pattern in the triathletes' urine indicated that their variation may have been related with the physical activity. Due to its high variation, 6-keto PGF(1α) stood out as a useful marker of the vasodilation and inhibition of the platelet aggregation of the PGI(2) linked to the physical exercise. The data obtained provided a global picture of changes in lipid peroxidation and vascular events as a consequence of chronic exercise.