title: Bactericidal/permeability-increasing protein in the reproductive system of male mice may be involved in the sperm-oocyte fusion.
abstract: Bactericidal/permeability-increasing protein (BPI) is a 455-residue (∼55 kDa) protein found mainly in the primary (azurophilic) granules of human neutrophils. BPI is an endogenous antibiotic protein that belongs to the family of mammalian lipopolysaccharide (LPS)-binding and lipid transport proteins. Its major function is to kill Gram-negative bacteria, thereby protecting the host from infection. In addition, BPI can inhibit angiogenesis, suppress LPS-mediated platelet activation, increase DNA synthesis, and activate ERK/Akt signaling. In this study, we found that Bpi was expressed in the testis and epididymis but not in the seminal vesicles, prostate, and solidification glands. BPI expression in the epididymis increased upon upregulation of testosterone, caused by injection of GNRH. In orchidectomized mice, BPI expression was significantly reduced, but its expression was restored to 30% of control levels in orchidectomized mice that received supplementary testosterone. The number of sperm fused per egg significantly decreased after incubation with anti-BPI antiserum. These results suggest that BPI may take part in the process of sperm-oocyte fusion and play a unique and significant role in reproduction.
authors.affiliation: Department of Histology and Embryology, Shanghai Jiaotong University School of Medicine, 280 South Chongqing Road, Shanghai 200025, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Li
authors.forename: Yue
authors.initials: Y
authors.lastname: Liu
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Xia
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Meige
authors.initials: M
authors.lastname: Lu
authors.forename: Yanqin
authors.initials: Y
authors.lastname: Hu
authors.forename: Chen
authors.initials: C
authors.lastname: Xu
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D001798:Blood Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects; D004822:Epididymis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D005307:Fertilization in Vitro; D020249:Hormone Replacement Therapy; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009919:Orchiectomy / Q000009:adverse effects; D009928:Organ Specificity; D012333:RNA, Messenger / Q000378:metabolism; D013084:Sperm-Ovum Interactions / Q000187:drug effects; D013737:Testis / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013739:Testosterone / Q000097:blood / Q000172:deficiency / Q000378:metabolism* / Q000627:therapeutic use; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000906:Antibodies; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D012333:RNA, Messenger; C021623:bactericidal permeability increasing protein; D013739:Testosterone