PHOSPHOLIPIDS AS A SOURCE OF ENERGY FOR MOTILITY OF BULL SPERMATOZOA

Abstract

Phospholipids from a variety of sources were effective in maintaining the motility of bull spermatozoa in a sugar-free medium under aerobic conditions. The effect was not due to catalysis of sperm glycolysis. In the presence of phospholipids the rate and duration of O2 consumption by bull spermatozoa was greatly increased. Ascorbic acid did not catalyze the oxidation of phospholipids by bull spermatozoa. The O2 consumption of bull spermatozoa in a medium containing glucose was not appreciably increased by the addition of lecithin. This, together with the demonstration that lecithin does not alter the rate of glycolysis, is further evidence that bull spermatozoa call upon oxidative processes as sources of energy for motility only when deprived of glycolyzable sugars. The similarity in the manner in which added phospholipid and the intracellular reserves are utilized by spermatozoa is in agreement with our previous conclusion that the intracellular reserves of the spermatozoa are phospholipid in nature.