Quantification of seminal plasma motility inhibitor/semenogelin in human seminal plasma.
Semenogelin I and II (Sg I and II) are the major components of human semen coagulum. The protein is rapidly cleaved after ejaculation by the chymotrypsin-like protease prostate-specific antigen (PSA), which results in the liquefaction of the semen coagulum and the progressive release of motile spermatozoa. One of the cleavage products of the protein, a 14-kDa protein, is a sperm motility inhibitor (seminal plasma motility inhibitor [SPMI]). We developed a monoclonal antibody (mAb) that is specific to the fragment of Sgs, SPMI, and a sandwich enzyme-linked immunosorbent assay (ELISA) system for the quantification of Sgs using this mAb. Then, we measured SPMI/Sg levels in human seminal plasma from healthy male volunteers (n = 100, aged 18-24 years). The mean level of SPMI/Sg in seminal plasma was 19 +/- 13 mg/mL (range, 4-68 mg/mL). Log-transformed SPMI/Sg levels were negatively correlated with the sperm motility (r = -0.229, P =.0220) and positively correlated with the total protein concentration (r = 0.793, P <.0001). This result supports that SPMI, one of the fragments of Sg, has its inhibitory effect on ejaculated spermatozoa in liquefied semen under physiological conditions.
Department of Urology, St Marianna University School of Medicine, Kawasaki, Japan.
Kaoru
K
Yoshida
Tadashi
T
Yamasaki
Miki
M
Yoshiike
Shoichi
S
Takano
Itaru
I
Sato
Teruaki
T
Iwamoto
D000328:Adult; D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009845:Oligospermia / Q000378:metabolism; D009994:Osmolar Concentration; D011506:Proteins / Q000032:analysis; D012661:Semen / Q000737:chemistry*; D029607:Seminal Vesicle Secretory Proteins / Q000032:analysis*; D013081:Sperm Motility
D000911:Antibodies, Monoclonal; D011506:Proteins; D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen