Detection of insulin-like growth factor binding protein-1 in cat implantation sites.
This study was undertaken to determine whether insulin-like growth factor binding protein-1 (IGFBP-1) was synthesized by the cat uterus and placenta during implantation and pregnancy. Endometrial and placental tissue explants from pregnant, pseudopregnant, and ovariectomized steroid-treated cats were cultured in the presence of 35S-methionine. Culture media proteins were separated by one-dimensional (1-D) and two-dimensional (2-D) SDS-PAGE, transferred to nitrocellulose, and immunostained using a rabbit polyclonal antibody against baboon IGFBP-1 and a murine monoclonal antibody to human IGFBP-1. The antibody cross-reacted with a protein with an M(r) = 30,000 and a pI = 5.1-5.4. Immunoreactive product was found in implantation site media from 16 days postcoitum (PC) through the end of pregnancy, and was confined to the superficial placental/junctional zone. Immunoreactivity was not detected in non-implantation site media until 7 wk PC and was never detected in serum or in media from liver, pseudopregnant endometrium, or endometrium from steroid-treated cats. Autoradiography and immunostaining of 2-D Western blots of culture media proteins demonstrated that implantation site and not non-implantation site tissue synthesized and released immunoreactive IGFBP-1 into the culture medium. 125Insulin-like growth factor-1 (IGF-1) specifically bound to this protein on 1-D Western ligand blots. Avidin-biotin immunocytochemistry utilizing the monoclonal antibody was used to localize IGFBP-1 in paraffin sections. Specific immunostaining was observed in the surface and glandular epithelium of the non-site endometrium throughout pregnancy, with stromal cell staining being detected later.(ABSTRACT TRUNCATED AT 250 WORDS)
Boomsma
R A
RA
Department of Biology, Trinity Christian College, Palos Heights, Illinois 60463.
Mavrogianis
P A
PA
Fazleabas
A T
AT
Jaffe
R C
RC
Verhage
H G
HG
D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000032:analysis* / Q000378:metabolism; D002415:Cats; D046508:Culture Techniques; D010064:Embryo Implantation; D004717:Endometrium / Q000737:chemistry* / Q000378:metabolism; D005260:Female; D015151:Immunoblotting; D007150:Immunohistochemistry; D018970:Insulin-Like Growth Factor Binding Protein 1; D010052:Ovariectomy; D010215:Papio; D010920:Placenta / Q000737:chemistry* / Q000378:metabolism; D011247:Pregnancy
D002352:Carrier Proteins; D018970:Insulin-Like Growth Factor Binding Protein 1