PITUITARY AND ADRENAL RESPONSES TO THE ANTI-PROGESTERONE AND ANTI-GLUCOCORTICOID STEROID RU 486 IN PRIMATES1

Abstract

RU 486 is a synthetic steroid with anti-progesterone and anti-glucocorticoid properties. While studying its acute effects on pituitary hormone secretion in cynomolgus monkeys, we found that RU 486 inhibited PRL secretion induced by an estrogen-progesterone synergy (P less than 0.025). By contrast, plasma levels of ACTH, arginine vasopressin and cortisol increased following RU 486 administration (P less than 0.05). Plasma FSH, LH, GH and TSH were unaffected by RU 486 treatment. Our findings suggest potential diagnostic and therapeutic applications of RU 486.