On the presence of prostatic secretion protein in rat seminal fluid

Eric Borgström, Åke Pousette, Per Björk, Bertil Högberg, Kjell Carlström, Birgitta Sundelin, Jan‐Åke Gustafsson

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6 Scopus citations


The copulating plug collected from the tip of the penis from rats immediately after decapitation contains a protein very similar and probably identical to PSP (prostatic secretion protein); this protein has earlier been purified from rat prostatic cytosol and characterized. The protein present in the copulating plug interacts with [3H]estramustine and binds to the antibody raised against rat PSP. The concentration of the protein in the copulating plug is 400 ng/mg of total protein, when measured using the radioimmunoassay technique developed earlier for measurement of PSPL in rat prostate. The [3H]destramustine-protein complex formed in a preparation of the copulating plug has an apparent molecular weight of about 50,000 and a sedimentation coefficient of about 3S when analyzed using sucrose density gradient centrifugation. The complex was retained on Concanavallin-A Sepharose indicating that the protein is a glycoprotein. Binding of the complex was also observed on hydroxylapatite and DEAE-Sephadex columns, from which it was eluted at 0.18 M KCl. Light microscope autoradiograms of rat sperms incubated with 125I-labeled PSP indicated that PSP is bound to all parts of the sperms. A macromolecule interacting with the PSP-antibodies is also present in human seminal fluid but at a concentration considerably lower than in rat seminal fluid. The present study shows that a macromolecule probably identical to prostatic secretion protein is present in the copulating plug from the rat. The biological role of this protein in normal male fertility is discussed.

Original languageEnglish (US)
Pages (from-to)425-432
Number of pages8
JournalThe Prostate
Issue number4
StatePublished - 1981


  • Estracyt®
  • prostate
  • prostatic secretion protein
  • secretory protein
  • seminal fluid

ASJC Scopus subject areas

  • Oncology
  • Urology


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