Carnitine and acetylcarnitine in motile and immotile human spermatozoa

Abstract

Human sperm were found to contain acetylcarnitine, carnitine, and only traces of propionylcarnitine and four-carbon acylcarnitines. 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 extracts of sperm from samples with a low degree of motility (0-10% motile), whereas it was 4.70 +/- 1.58 in samples which were 40-80% motile. The possible significance of this difference with regard to the degree of acylation of coenzyme A is discussed.

Paradoxical increase of sperm motility and seminal carnitine associated with moderate leukocytospermia in infertile patients

“…Indeed, a close relationship exists between motility and the cellular carnitine content and its acetylation state (56,57). Statistical positive correlation had been found between seminal carnitine and total sperm motility in fertile (58) and infertile men (59)(60)(61).…”

Influence of various substrates on the acetylcarnitine:carnitine ratio in motile and immotile human spermatozoa

“…Other experiments have indicated that the acylation state of carnitine may be correlated with the ability of spermatozoa to move. Johansen & Böhmer (1979) and Golan, Weissenberg & Lewin (1984) have demonstrated that the degree of acetylation of carnitine is greater in motile than in immotile human spermatozoa. Tanphaichitr (1977) and Jeulin, Soufir & Jouannet (1981) have reported that addition of acetylcarnitine to ejaculated human spermatozoa stimulated motility slightly.…”

A Comparative Study of Erythrocytic Total, Free, Short-chain Acyl and Long-chain Acyl Carnitine Concentrations in Arabian Camel (Camelus dromedarius) with Different Species

“…Carnitine involvement in energy metabolism has been extensively studied in tissues such as liver (Hulse and Henderson 1980), skeletal muscle (Cederblad et al 1976), heart (Bahl et al 1981), kidney (Huth and Shug 1980), brain (Natecz and Natecz, 1996), serum , lymphocytes (Alhomida 2000), urine (Al-Kholaifi and Alhomida 1999), milk (Alhomida 1996) and sperm (Golan et al 1984). A study in our laboratory showed that the concentrations of carnitine in the Arabian camel tissues are higher than in most other species and a higher proportion of acyl carnitine compared to free carnitine exists in plasma and skeletal muscle (Alhomida et al 1995a).…”