RESUMO
The trans isomer of a bromotriphenylethylene (TBP) inhibits spontaneous mammary carcinogenesis in (C3H x RIII)F1 females, which received a diet containing 20 ppm of the chemical: intact, spayed, and spayed and pituitary implanted animals. Mammary carcinogenesis is inhibited even if the administration of the compound starts late in life. TBP has no activity on mammary carcinogenesis of castrated males implanted with an ovary.
Assuntos
Antagonistas de Estrogênios/farmacologia , Neoplasias Mamárias Experimentais/prevenção & controle , Estilbenos/farmacologia , Animais , Castração , Antagonistas de Estrogênios/administração & dosagem , Feminino , Isomerismo , Masculino , Camundongos , Hipófise/fisiologiaRESUMO
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 micrograms/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 micrograms/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. Our study confirms that prolactin is a key hormone involved in murine mammary carcinogenesis and that it can act directly on the mammary gland by stimulaing the level of its own receptor.
Assuntos
Neoplasias Mamárias Experimentais/induzido quimicamente , Prolactina , Estilbenos/farmacologia , Animais , Feminino , Camundongos , Camundongos Endogâmicos C3H , Hipófise/transplante , Prolactina/antagonistas & inibidores , Prolactina/sangue , Receptores de Superfície Celular/metabolismo , EstereoisomerismoRESUMO
Daily administration of a brominated triphenylethylene (TBP), to rats which received 20 mg of DMBA p. o. inhibits mammary carcinogenesis. The effect appears even with very small doses (i ppm in the diet) and seems to be dose related. With one exception (an adenofibroma) the tumours in control and treated animals were malignant. Administration of TBP prevents the appearance of corporea lutea in the ovaries but not the usual necrosis of the adrenal cortex.
