Effect of l-carnitine on human neutrophil activity.

The effect of l-carnitine on human neutrophil oxidative metabolism was investigated, both on superoxide production and luminol amplified chemiluminescence (CL) in phorbol-myristate-acetate (PMA) stimulated cells. L-carnitine either preincubated 10 minutes with the cells, before PMA challenge, or added simultaneously to the stimulator, inhibited superoxide generation. When tested in an O2- -generating system, such as xanthine-xanthine oxidase, l-carnitine did not act as an O2- scavenger. On the PMA induced CL response the drug was ineffective as an inhibitor, if preincubated with the cell suspension before activation. When added together with PMA, l-carnitine significantly inhibited the CL. Taken together the results reveal that the drug might affect the interaction of PMA with its specific receptor in human neutrophils, that is protein kinase C.