Carnitine and acetylcarnitine in motile and immotile human spermatoza

Human sperm were found to contain acetylcarnitine, carnitine, and only tracers of propionylcarnitine and four-carbon acetylcarnitines. Carnitine and acetylcarnitine were present in higher concentrations in sperm than in the corresponding seminal fluid samples, and the degree of acylation of carnitine was greater in sperm than in seminal plasma. The ratio of acetylcarnitine/carnitine was 1.77 ± 0.69 in extract of sperm from samples with a low degree of motility (0-10% motile), whereas it was 4.70 ± 1.58 in samples which were 4-0-40% motile. The possible significance of this difference with regard to the degree of acylation of coenzyme A is discussed.