Trophoblast-derived interleukin-6 (IL-6) regulates human chorionic gonadotropin release through IL-6 receptor on human trophoblasts.
We examined the capacity of trophoblast-derived interleukin-6 (IL-6) to stimulate secretion of placental hormones, including hCG. IL-6 stimulated hCG secretion by trophoblasts to a level similar to that stimulated by a GnRH analog. The analog, however, released hCG by an IL-6-independent mechanism because PM-1, a monoclonal antibody specific for IL-6 receptors (R), failed to block GnRH-mediated responses, but completely blocked IL-6-mediated hCG secretion, suggesting the existence of two distinct regulatory pathways for hCG release. Immunohistochemical analysis with another IL-6-R-specific antibody, MT-18, showed that IL-6-R was located only on the trophoblast layer of the placenta. Our data revealed the existence of a local regulatory network by which trophoblast-derived IL-6 interacts with IL-6-R on the trophoblasts, resulting in hCG release. Thus, two different regulatory networks, an IL-6 and IL-6-R system and a GnRH and GnRH-R system, regulate hCG release by human trophoblasts independently.
Nishino
E
E
Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
Matsuzaki
N
N
Masuhiro
K
K
Kameda
T
T
Taniguchi
T
T
Takagi
T
T
Saji
F
F
Tanizawa
O
O
D000911:Antibodies, Monoclonal; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000494:pharmacology; D006728:Hormones / Q000494:pharmacology; D006801:Humans; D015850:Interleukin-6 / Q000494:pharmacology*; D007700:Kinetics; D016729:Leuprolide; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D011994:Recombinant Proteins / Q000494:pharmacology; D014327:Trophoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D006063:Chorionic Gonadotropin; D006728:Hormones; D015850:Interleukin-6; D011994:Recombinant Proteins; D007987:Gonadotropin-Releasing Hormone; D016729:Leuprolide