Possible evidence that dehydroepiandrosterone sulfate (DHA-S) stimulates cervical ripening by a membrane-mediated process: specific binding-sites in plasma membrane from human uterine cervix.
Fetal adrenal steroid, dehydroepiandrosterone sulfate (DHA-S) is well known to promote cervical ripening in late pregnancy. The presence of sites specifically binding the DHA-S in plasma membrane was studied in human cervical fibroblasts prepared from pregnant uterus. The fibroblasts were incubated with [3H] DHA-S and then fractionated into plasma membranes, cytosol, nuclei, and other organella debris. The specific activity of 3H-count in the plasma membrane fraction was enriched approximately 7-fold compared with the whole homogenate. When the isolated plasma membrane preparations from the fibroblasts were exposed to [3H] DHA-S, the binding showed saturation kinetics; an apparent equilibrium dissociation constant (Kd) of 12 nM, and the binding capacity (Bmax) of 1.25 pmol/mg protein. The present results suggest that DHA is bound to and recognized by components in plasma membrane, and may exert its action on cervical ripening through the membrane-mediated processes.
Ohno
T
T
Department of Obstetrics and Gynecology, Gifu University School of Medicine, Japan.
Imai
A
A
Tamaya
T
T
D001665:Binding Sites; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002584:Cervix Uteri / Q000187:drug effects* / Q000502:physiology; D003687:Dehydroepiandrosterone / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D019314:Dehydroepiandrosterone Sulfate; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D011247:Pregnancy; D014316:Tritium
D014316:Tritium; D003687:Dehydroepiandrosterone; D019314:Dehydroepiandrosterone Sulfate