Binding of human sex hormone-binding globulin-androgen complexes to the placental syncytiotrophoblast membrane.
We have found that human SHBG complexed with androgens binds specifically to the plasma membrane of human placental syncytiotrophoblast. Apparent equilibrium association constants were 5.3.10(11) M-1 for SHBG-testosterone complex and 1.1.10(11) M-1 for SHBG-5 alpha-dihydrotestosterone. Devoid of steroid, SHBG did not bind to the membrane. This suggests that the specific membrane binding of SHBG-androgen complexes is a step of the mechanism of androgen action on syncytiotrophoblast.
Krupenko
N I
NI
Institute of Bioorganic Chemistry, Byelorussian Academy of Sciences, Minsk, U.S.S.R.
Avvakumov
G V
GV
Strel'chyonok
O A
OA
D002462:Cell Membrane / Q000378:metabolism; D005260:Female; D006801:Humans; D007700:Kinetics; D008871:Microvilli / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011485:Protein Binding; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism*; D014327:Trophoblasts / Q000378:metabolism*
D012738:Sex Hormone-Binding Globulin; D013739:Testosterone