THE ANTIGLUCOCORTICOID ACTION OF MIFEPRISTONE

Glucocorticoid hormones influence the physiological activity of almost all cell types in the mammal, This is accomplished via a soluble rece ptor that, in the presence of an appropriate steroid, modifies the act ivity of RNA polymerase by binding to the site where different factors assemble for the initiation of cell transcription, The development of antiglucocorticoids has permitted the molecular elucidation of a numb er of underlying events, Contrary to the classical view, it is now cle ar that the affinity, stability and activability of the glucocorticoid receptor in the presence of a steroid are cell and/or tissue dependen t events, The antiglucocorticoid RU 38486 can even activate transcript ion by binding to sites distinct from those that process transactivati on by the agonist. Furthermore, glucocorticoids can some times activat e the mineralocorticoid receptor, whereas mineralocorticoids can bind the glucocorticoid receptor, Since mifepristone is devoid of adverse t oxicity, it has been used for the paraclinical diagnosis of the hypoth alamus pituitary-adrenal axis in normal volunteers, subjects with diso rders of the behaviour, and the treatment of Cushing's disease, Howeve r, the whole spectrum of cell-specific processes that are antagonized by RU 38486 suggests wide ranging possibilities in the eventual applic ation of antiglucocorticoids.