Human chorionic gonadotropin beta-core fragment is present in the human placenta.
The presence of hCG beta-core fragment (beta-core) in the human placenta has been controversial. To clarify its presence in the villous tissue, first, we developed an enzyme immunoassay which is highly specific for beta-core. Then, we investigated the presence of beta-core immunoreactivity in the supernatants of placental organ culture and those of primary culture of trophoblasts as well as in the placental extracts at different stages of gestation. The immunoreactivity of beta-core was demonstrated in each sample, and the amount was at least 5% of intact hCG immunoreactivity. Immunohistochemical analysis of the placental tissue showed localization of beta-core immunoreactivity to the syncytiotrophoblast. Western blot analysis of the supernatants of organ culture as well as urine samples of pregnant women showed two major bands with molecular weight of approximately 15000. On the other hand, beta-core immunoreactivity in the pregnant sera ranged from 0.1 to 0.19% of intact hCG immunoreactivity. These results suggest the presence and possible secretion of beta-core fragment in the human placenta, and its immunoreactivity in the serum is likely to be reduced due to its short half life in the maternal blood.
Udagawa
A
A
Department of Obstetrics and Gynecology, Nagoya University School of Medicine, Japan.
Okamoto
T
T
Nomura
S
S
Matsuo
K
K
Suzuki
H
H
Mizutani
S
S
D002457:Cell Extracts; D002478:Cells, Cultured; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000032:analysis* / Q000097:blood / Q000652:urine; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D009924:Organ Culture Techniques; D010446:Peptide Fragments / Q000032:analysis* / Q000097:blood / Q000652:urine; D010920:Placenta / Q000737:chemistry*; D011247:Pregnancy; D012680:Sensitivity and Specificity; D014327:Trophoblasts
D002457:Cell Extracts; D018997:Chorionic Gonadotropin, beta Subunit, Human; D010446:Peptide Fragments; C063554:urinary gonadotropin fragment