著者

神谷 研二 CLIFTON KELLY H. GOULD MICHAEL N. YOKORO KENJIRO

出版者

Journal of Radiation Research 編集委員会

雑誌

Journal of Radiation Research (ISSN:04493060)

巻号頁・発行日

vol.32, no.2, pp.181-194, 1991

被引用文献数

2

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We have developed an in vitro-in vivo transplantation assay for measuring the concentration of clonogenic epithelial cells in cell suspensions of rat mammary tissue. Rat mammary clonogens from organoid cultures are capable of the same degree of PLDR as clonogens in vivo. The growth and differentiation of mammary clonogens to alveolar colonies or ductal colonies is regulated as follows: a) in the presence of E<SUB>2</SUB> and high prolactin (Prl), cortisol induces mammary clonogens to proliferate and differentiate to form alveolar colonies which secrete milk and begin losing clonogenic potential, b) in cortisol deficient rats, Prl and E<SUB>2</SUB> synergistically stimulate non-secretory ductal colonies, formation of which retain clonogenic potential, c) E<SUB>2</SUB> without progesterone stimulates alveolar colony formation in the presence of cortisol and high Prl, d) progesterone inhibits mammary clonogen differentiation to milk-producing cells and induces ductogenesis in a dose responsive fashion in the presence of E<SUB>2</SUB>, cortisol and high Prl. High prolactin levels coupled with glucocorticoid deficiency increases the susceptibility to mammary carcinogenesis following low dose radiation exposure by increasing the number of total mammary clonogens which are the presumptive target cells and by stimulating their proliferation after exposure.