Changes in phospholipids of ram spermatozoa during migration through the epididymis and possible origin of prostaglandin F2α in testicular and epididymal fluid

Abstract A study of the lipid composition of ram testicular and ejaculated spermatozoa was made in an attempt to resolve conflicting results in the literature. Testicular spermatozoa were found to contain more than double the amount of phospholipid present in ejaculated spermatozoa. Most phospholipid components, including choline plasmalogen, decrease substantially in concentration during migration of the spermatozoa through the male reproductive tract. Phosphatidylserine, ethanolamine phosphoglycerides and cardiolipin components accounted for the greatest relative decreases in concentration, the former decreasing by approximately nine tenths. Of the phospholipid-bound fatty acids the most pronounced change occurs in palmitic during migration of spermatozoa through the reproductive tract. There is a net loss of approx. 500 μg of palmitic acid for every 10 9 spermatozoa. The loss of arachidonic acid was particularly interesting, and prompted a study of the prostaglandin content of testicular and epididymal fluids, since arachidonic acid can act as a precursor of prostaglandin. The concentration of prostaglandin F 2α found in the testicular and epididymal fluid is considerably in excess of that found in venous plasma of the ram.