Endogenous and exogenous reproductive hormones have long been recognized as a risk factor for @entity0 . These hormones are thought to exert their influence by altering the kinetics of cell proliferation, differentiation or @entity194 resulting in an increased population of susceptible cells. Prolonged exposure to endogenous hormones (predominantly @entity172 and @entity7828 ) resulting from either early menarche, late menopause, and absent or reduced ovarian cyclic functions due to parity are associated with an increased risk. Oophorectomy, in contrast, provides a protection inversely related to age at ablation. The influence of exogenous hormones (birth control pills, hormone replacement therapy, etc.) on mammary carcinogenesis remains a controversial issue. The various viewpoints will be discussed. Among @entity2608 in captivity, experimental exposure to a variety of synthetic oral contraceptive @entity230 has resulted in a variety of proliferative changes including @entity189 in the mammary duct system. A much higher proportion of @entity189 was observed among those receiving progestational hormones in pure form or in combination with @entity172 . Pure estrogenic compounds did not cause as severe a proliferation or atypia in as high a proportion as observed when progestational hormones were used in pure or combined form. In view of this finding it is important to use caution when considering addition of @entity7828 to hormone replacement therapy in an effort to prevent @entity1204 . This is particularly important if the @entity1 has other risk factors for @entity0 .

The influence of endogenous and exogenous reproductive hormones on the mammary glands with emphasis on experimental studies in XXXX .

@entity172 :: ('MESH:D004967', 'Chemical') :: ['estrogens'] @entity230 :: ('MESH:D013256', 'Chemical') :: ['steroids'] @entity1204 :: ('MESH:D016889', 'Disease') :: ['endometrial carcinomas'] @entity1 :: ('9606', 'Species') :: ['patient'] @entity0 :: ('MESH:D001943', 'Disease') :: ['breast carcinoma'] @entity189 :: ('MESH:D002277', 'Disease') :: ['severe atypias and carcinoma', 'atypical hyperplasia and carcinoma'] @entity7828 :: ('MESH:D011372', 'Chemical') :: ['progestins'] @entity194 :: ('MESH:D001284', 'Disease') :: ['atrophy'] @entity2608 :: ('9544', 'Species') :: ['rhesus monkeys']
@entity2608 :: (9544,Species) :: ['rhesus monkeys']
