Studies on the constancy of transudated and locally produced proteins in human seminal plasma

An overall constancy in the total protein profile of human seminal plasma (HSP) as determined by gel filtration chromatography and high-resolution electrophoresis was found in six healthy volunteers. Thirteen different proteins were identified by double immunodiffusion in five individual HSP samples each previously subjected to gel filtration. It was also found that comparatively large amounts of yet unidentified low-molecular-weight (less than 12,000) compounds occurred in all HSP samples. Of eight specific proteins in consecutive samples collected from one individual, large intra-individual variations were found in some of the proteins. The largest variations (about 100%), for both concentration and total amount, were noted for alpha 1-antitrypsin, transferrin, IgA, and secretory IgA. Albumin and lactoferrin were rather stable and varied less than 20% between samples. It is suggested that HSP-albumin may be used as a reliable marker of transudation of serum proteins to the genital tract. Likewise, lactoferrin could be used as a marker for the secretion of seminal vesicle proteins, since it reflects the functional status of these glands.