Effects of carnitine and some related compounds on the motility of rat spermatozoa from the caput epididymidis

Abstract

Spermatozoa were collected from the rat caput epididymidis by micropuncture and their motility was assessed after dilution in physiological saline containing carnitine or related compounds. L(+)-Carnitine caused, 2 min after dilution, a transient stimulation of the motility of spermatozoa with low initial motility. No stimulatory effects were seen on spermatozoa which had high initial motility. The D-isomer inhibited the motility of spermatozoa with high initial motility after 2 min and all compounds tested appeared to inhibit, at 20 min after dilution, the motility of spermatozoa with high initial motility. Acetyl-L-carnitine and acetyl-D-carnitine stimulated the motility of spermatozoa with low initial motility. Carnitine may be important in development by spermatozoa of the potential for motility and in maintenance of mature spermatozoa in a quiescent state.