The phospholipid-bound fatty acids and aldehydes of mammalian spermatozoa

The Phospholipid Composition of Human Spermatozoa and Seminal Plasma

“…The amount of phospholipid extracted from human spermatozoa is similar to the amount extracted from the ram (Scott et al, 1967) and bull (Pursel & Graham, 1967) despite the use of different extraction procedures, but is lower than the figures quoted for the boar (Johnson et al, 1969;Poulos et al, 1972 Stanley (1957) in at least three other species (Poulos et al, 1972).…”

“…The phospholipid composition of human spermatozoa appears to resemble that of the boar more closely (Johnson et al, 1969;Poulos et al, 1972) than that of the ram (Scott et al, 1967;Quinn & White, 1967) or bull (Masaki & Hartree, 1962;Pursel & Graham, 1967). Choline plasmalogen comprises only 3% and 10% of human and boar sperm phospholipids, respectively, whereas it is by far the major component of ram and bull spermatozoa.…”

“…Thus, human spermatozoa are fairly resistant to rapid cooling to 0°C (Wales & White, 1959;White & Wales, 1960), while boar spermatozoa are very sensitive to such changes (Lasley & Bogart, 1944). Moreover, although the phospholipid composition of rabbit spermatozoa fairly closely resembles that of the boar (Poulos et al, 1972), rabbit spermatozoa are relatively resistant to cold shock (Wales & White, 1959;White & Wales, 1960). The total phospholipid com¬ position of the various species, however, gives no indication of the lipid com¬ position of the acrosome or of the outer sperm membranes, and since both of these organdies, and in particular the former, appear to be disrupted by coldshock in some species (Quinn, White & Cleland, 1969;A.…”

“…(Poulos et al, 1972). These two components are included in the sphingomyelin zone since in most instances they were not separated sufficiently from the major sphingo¬ myelin area to permit accurate quantification.…”

Evidence that phospholipid protects ram spermatozoa from cold shock at a plasma membrane site

“…Normal ram spermatozoa have very little myristic acid in their phospholipids (Poulos et al, 1973) and dimyristoyllecithin was, therefore, included in the exogenous phospholipid as a marker to check fusion of the liposomes with the spermatozoa. Fatty acid analysis of the spermatozoa, however, showed no increase in the proportion of myristoyl (C14:0) to palmitoyl (C,6:0) esters when the washed spermatozoa were incubated with the exogenous phospholipid mixture: the ratio of C14:0 to C16:0 was 1-04 at 0 h and 0-73 at 3 h. The immediate protection afforded against cold shock by exogenous phospholipid further argues against a slow exchange of membrane components between the spermatozoa and the liposomes.…”