Effect of sports activity on carnitine metabolism - Measurement of free carnitine, gamma-butyrobetaine and acylcarnitines by tandem mass spectrometry

The effects of sports activity on carnitine metabolism were studied using m ass spectrometry. Serum levels of free carnitine, acylcarnitines (acetylcar nitine, propionylcarnitine, C4-, C5- and C8-acylcarnitine) and gamma-butyro betaine, a carnitine precursor, were determined by tandem mass spectrometry in liquid secondary ion mass ionization mode. The coefficients of variatio n at three different concentrations were 2.8 similar to 7.9% for gamma-buty robetaine, and 1.2 similar to 6.7% for free carnitine. The recoveries added to serum were 109.1% for gamma-butyrobetaine, 89.3% for free carnitine. Sp orts activity caused increased serum levels of gamma-butyrobetaine, acetylc arnitine, C4- and C8-acylcarnitines and decreased serum levels of free carn itine. This method requires a small amount of sample volume (20 mu l of ser um) and short total instrumental time for the analysis (1 h for preparation , 2 min per sample for mass spectrometric analysis). Therefore, this method can be applied to study carnitine metabolism under various conditions that affect fatty acid oxidation. (C) 1999 Elsevier Science BN. All rights rese rved.