Sialic acid content of human spermatozoa and seminal plasma in relation to sperm counts.
Sialic acid levels were determined in spermatozoa and seminal plasma of 47 semen samples divided into two groups according to sperm counts. Group 1, up to 40 x 10(6) sperm/ml seminal fluid and group 2, above 40 x 10(6) sperm/ml seminal fluid. The content of sialic acid in spermatozoa ranged from 4.4-28.1 micrograms/10(8) spermatozoa and from 70-95 mg/100 ml seminal plasma. Sialic acid was significantly higher in sperm and lower in seminal plasma of group 1 as compared to group 2. The lower content of sialic acid in seminal plasma might have a deteriorating effect on structural integrity of sperm.