[Inhibition of the anti-glucocorticosteroid effect of RU486 on the growth of mouse fibroblasts in culture by the immunosuppressor kf506]].
The growth of mouse L-929 fibroblasts in culture is inhibited by dexamethasone, a synthetic glucocorticosteroid, and this effect is itself suppressed by the antiglucocorticosteroid RU486 (mifepristone). Neither RU486 nor the immunosuppressant FK506 alone influence L-929 growth, and FK506 does not modify dexamethasone action. However, FK506 suppresses the antiglucocorticosteroid activity of RU486. The implication of the "anti-antagonist" activity of FK506 in its immunosuppressant properties has still to be explained. The role of the recently cloned, FK506-binding, p59 immunophilin, which binds to the heat shock protein hsp90 which itself interacts with the glucocorticosteroid receptor, is discussed.
Jung-Testas
I
I
INSERM U.33, Laboratoire Hormones, Le Kremlin-Bicêtre, France.
Delespierre
B
B
Baulieu
E E
EE
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology; D051379:Mice; D015735:Mifepristone / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000494:pharmacology*; D016559:Tacrolimus / Q000494:pharmacology*
D015735:Mifepristone; D003907:Dexamethasone; D016559:Tacrolimus