title: IGF and insulin action in the mammary gland: lessons from transgenic and knockout models.
abstract: Transgenic and knockout mice have become valuable experimental systems with which to study specific molecular events within the mammary gland of an intact animal. These models have provided a wealth of information about the effects of a number of oncogenes and growth factors. This review focuses on results obtained from the application of transgenic and knockout models to determine the roles of insulin and insulin-like growth factors (IGF) in the regulation of mammary gland development, lactation and tumorigenesis. Transgenic models which overexpress IGF-I or -II display specific alterations in mammary gland development and an increased incidence of mammary tumors. Analysis of mammary gland development in knockout mice which are deficient in IGF-I or the IGF-I receptor supports the conclusion that the IGF system is important for normal mammary gland development. This review discusses these observations in detail and attempts to fit them into a larger picture of IGF and insulin action in the mammary gland.
authors.affiliation: USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA. dhadsell@bcm.tmc.edu
authors.forename: D L
authors.initials: DL
authors.lastname: Hadsell
authors.forename: S G
authors.initials: SG
authors.lastname: Bonnette
mesh_terms: D000818:Animals; D001940:Breast / Q000502:physiology*; D001943:Breast Neoplasms / Q000503:physiopathology; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D007335:Insulin-Like Growth Factor II / Q000502:physiology*; D008321:Mammary Glands, Animal / Q000502:physiology*; D015674:Mammary Neoplasms, Animal / Q000503:physiopathology; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic
chemical_list: D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II