Carnitine-binding related supressed oxygen uptake by spermatozoa.

L-carnitine (25 mM) reduced oxygen uptake immediately by 40% in ejaculated bovine spermatozoa, but not in ejaculated human spermatozoa or in spermatozoa from bovine and rat epididymis. [3H]-L-carnitine was bound five times as much to ejaculated bovine spermatozoa as to bovine spermatozoa from the cauda epididymis and to human ejaculated spermatozoa. This indicates the presence of a factor in the accessory male sex organs which, through changes in the membrane and/or intracellulary, increases the [3H]-L-carnitine binding sites and makes the spermatozoa susceptible to carnitine inhibition.