Long-term effects of perinatal exposure to hormones on normal and neoplastic mammary growth in rodents: a review.

Exposure of mammals to hormones and drugs during pregnancy sometimes results in profound consequences in the offspring. In this review, the long-term effects of perinatal exposure to hormones on the mammary gland in female rodents at advanced ages are discussed as a model for possible human consequences of antenatal exposure to sex hormones. In general, antenatal hormone treatments may influence the development and growth of the mammary gland. Perinatal treatment with estrogen, androgen, progesterone, or even prolactin in some cases induces not only irreversible abnormality of mammary growth but also influences spontaneous and carcinogen-induced mammary tumorigenesis. Effects of neonatal hormone treatment on mammary tumorigenesis, which appear to be mainly due to the endogenous hormone imbalance produced, vary according to the time and period of the treatment and to the species and/or strain employed.