INHIBITION OF PROLACTIN-INDUCED MAMMARY-CANCER IN C3HF (XVII) MICE WITH THE TRANS ISOMER OF BROMOTRIPHENYLETHYLENE

Abstract

C3Hf (XVII) mice never develop spontaneous mammary tumors. However, the transplantation of an isologous pituitary gland under their kidney capsule is followed by a 10-fold increase in serum and pituitary prolactin content (180 ng/ml and 20 .mu.g/mg of tissue, respectively), concomitant with an increase of prolactin receptors in mammary glands. Under these conditions, mammary tumors appear in 90% of the mice. If a racemic brominated triphenylethylene, i.e., broparestrol, is administered, serum and pituitary prolactin decrease rapidly (10 ng/ml and 4 .mu.g/mg of tissue, respectively), and prolactin receptors in the mammary gland are markedly reduced. This compound also inhibits the development of normal mammary glands, prevents mammary carcinogenesis and unexpectedly causes a significant atrophy of the ovaries. Prolactin is a key hormone involved in murine mammary carcinogenesis. It can act directly on the mammary gland by stimulating the level of its own receptor.