title: Beta-microseminoprotein in serum correlates with the levels in seminal plasma of young, healthy males.
abstract: Beta-microseminoprotein (MSP) is one of the most abundant proteins secreted by the prostate gland. Because MSP is also synthesized in nonreproductive organs, the establishment of a solid relationship between the levels of MSP in serum and semen is crucial for future studies connecting MSP with aging or diseases of the prostate gland. We developed a specific, competitive, europium-based immunoassay to measure MSP in serum and seminal plasma. We also produced recombinant MSP in insect cells using baculo virus and purified it to homogeneity by a novel approach with ethanol extraction and gel filtration. The median values of MSP in 205 young men were 12 microg/L (2.5-97.5 percentile, 4.9-26 microg/L) in serum and 0.53 g/L (2.5-97.5 percentile, 0.13-2.0 g/L) or 1.8 mg (2.5-97.5 percentile, 0.32-6.6 mg) in seminal plasma. MSP in serum showed significant correlation to MSP in seminal plasma (r = .50, P < .001). Significant correlations were also found in seminal plasma between MSP and prostate-specific antigen (PSA) (r = .65, P < .001) and between MSP and Zn(2+) (r = .54, P < .001). The yield of recombinant MSP in culture medium was 35 mg/L or higher, and recovery following ethanol extraction was 80%-90%. MSP in serum reflects the prostate secretion of MSP, and correlations were also found in seminal plasma between MSP and PSA and Zn(2+). This suggests that MSP in serum can be used as a marker of prostate secretion, despite the contribution from extra prostatic tissues.
authors.affiliation: Department of Laboratory Medicine, Division of Clinical Chemistry, Lund University, Malmö University Hospital, SE-205 02 Malmö, Sweden.
authors.forename: Camilla
authors.initials: C
authors.lastname: Valtonen-André
authors.forename: Charlotta
authors.initials: C
authors.lastname: Sävblom
authors.forename: Per
authors.initials: P
authors.lastname: Fernlund
authors.forename: Hans
authors.initials: H
authors.lastname: Lilja
authors.forename: Aleksander
authors.initials: A
authors.lastname: Giwercman
authors.forename: Ake
authors.initials: A
authors.lastname: Lundwall
mesh_terms: D006801:Humans; D007118:Immunoassay; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood / Q000378:metabolism; D029584:Prostatic Secretory Proteins / Q000097:blood* / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D012661:Semen / Q000378:metabolism*; D015032:Zinc / Q000097:blood / Q000378:metabolism
chemical_list: D029584:Prostatic Secretory Proteins; D011994:Recombinant Proteins; C043076:beta-microseminoprotein; D017430:Prostate-Specific Antigen; D015032:Zinc