GESTRINONE IS A SYNTHETIC STEROID HORMONE THAT ACTS AS AN ANTI-PROGESTIN AND ALSO HAS SOME ANDROGENIC ACTIVITY. ITS MECHANISM OF ACTION CONSISTS OF SUPPRESSION OF THE RELEASE OF PITUITARY GONADOTROPINS. GESTRINONE ALSO INTERACTS WITH THE ENDOMETRIUM, INHIBITING ITS GROWTH. THE INHIBITION IS THE RESULT OF GESTRINONE'S INTERACTION WITH THE ANDROGEN RECEPTOR; THIS IS ALSO THE REASON FOR ANDROGENIC SIDE EFFECTS. GESTRINONE HAS BEEN SHOWN TO INTERACT WITH THE ESTROGEN RECEPTOR, THE ANDROGEN RECEPTOR, AND THE PROGESTERONE RECEPTOR.