engleski

Glutathione depletion is not the reason for subnormal CK values measured by common methods

The inappropriately low creatine kinase (CK) values, usually <20 U/L, measured at 37 oC in certain patients, have been observed for the long time, without satisfactory explanation. This fact has prompted us to test if oxidative stress might be responsible for this phenomenon. The thiol groups determining the enzyme conformation are easily oxidised, which is why reagents fo rthe determination of CK activity contain thiol-reducing agents such as N-acetylcysteine. The aim of this study was to test whether the addition of glutathione (GSH, Sigma) could recover the activity. The sera were collected from 25 patients, hospitalized for various types of trauma or burns, whose CK activity was below 20 U/L, despite the fact that their myoglobine was normal or high, and case histories confirmatory of the muscle damage. However, neither the addition of physiological (3 uM/L) nor supraphysiological (6, 10, 15, 20 uM/L) doses of GSH increased the enzyme activities. The time frame seemed not to be critical either (the addition of GSH immediately after blood drawing or 2, 8 and 24 hours afterwards had no effect whatsoever). In conclusion, it seems that a mechanism other than oxidative stress is responsible for the subnormal CK activities in certain patients.

glutathione depletion; CK

nije evidentirano