Glycerylphosphorylcholine and phosphorylcholine in semen, and their relation to choline

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Abstract
Glycerylphosphorylcholine and phosphorylcholine accounted for the bulk of "water-soluble bound choline" and "acid-soluble, difficulty-hydrolysable phosphorus" in the seminal plasma of various mammals. In man, the content of phosphorylcholine exceeded considerably that of glycerylphosphorylcholine, whereas in ram, bull, boar, goat, stallion and rabbit practically the whole of bound choline was accounted for as glycerylphosphorylcholine. Bull and boar possess a particularly rich source of glycerylphosphorylcholine in the epididymis. Cock semen contained a small quantity of phosphorylcholine but no glycerylphosphorylcholine. In addition to chromatographic means, glycerylphosphorylcholine was also identified by chemical isolation; 470 mg of the crystalline cadmium salt was obtained from 40 ml of ram seminal plasma. Glycerylphosphorylethanolamine was detected in trace amounts in some samples of seminal plasma, but phosphorylethanolamine was altogether absent. Phosphorylcholine was readily dephosphorylated in semen after ejaculation. Glycerylphosphorylcholine was neither dephosphorylated nor changed in any other way by spermatozoa. Lecithin usually stimulated the O2 uptake of spermatozoa, but this was not associated with an enzymic hydrolysis of ester bonds or the liberation of acid-soluble metabolic products. Lysolecithin, on the other hand, had a marked inhibitory effect on sperm respiration and motility.