Association of exogenous phospholipids with spermatozoa.

Boar, bull and ram spermatozoa were studied after incubation in a medium containing phospholipids. Autoradiography and birefringent examination of spermatozoa after incubation with labelled phosphatidylcholine indicated that liposomes of this phospholipid associated with spermatozoa. The association was almost instantaneous. The large multilayer liposomes formed during the experimental procedure resulted in a few of the spermatozoa acquiring most of the phosphatidylcholine. Little phosphatidylcholine was observed unassociated with spermatozoa although measurements of the partition between spermatozoa and medium showed that only boar spermatozoa associated with almost all the phospholipid. No evidence was obtained that phosphatidylethanolamine or phosphatidylinositol associated with the spermatozoa.