Mhatre M C, Shah P N, Juneja H S
J Natl Cancer Inst. 1984 Jun;72(6):1411-6.
A clear positive correlation between circulating levels of prolactin (Prl) and morphologic development as well as DNA synthetic index in the mammary gland was established in young virgin Holtzman rats exposed to constant light from birth. The observed elevated level of circulating Prl by virtue of its morphogenic and mitogenic properties induced changes in mammary epithelium [numerous actively differentiating terminal end buds into alveolar buds (AB)] highly susceptible for the action of 7,12-dimethylbenz[a]anthracene [(DMBA) CAS: 57-97-6]. Conversely, substitution treatment with melatonin in such a model caused a significant decrease in both Prl and 17 beta-estradiol (E2) levels as well as in the morphologic and DNA synthetic pattern of the mammary gland. Administration of 2-bromo-alpha- ergocryptin in these animals caused a significant decrease in the plasma level of Prl (without affecting the level of E2) and a decrease in the density of AB and in DNA synthesis. These changes impaired the mammary gland responsiveness to DMBA as seen from the significant decrease in the incidence of mammary carcinoma.
在出生后持续光照的幼年未孕霍尔兹曼大鼠中，泌乳素（Prl）的循环水平与乳腺的形态发育以及DNA合成指数之间建立了明确的正相关关系。观察到循环Prl水平升高，凭借其形态发生和促有丝分裂特性，诱导乳腺上皮发生变化[众多活跃分化的终末芽发育为肺泡芽（AB）]，对7,12 - 二甲基苯并[a]蒽[（DMBA），CAS：57 - 97 - 6]的作用高度敏感。相反，在此模型中用褪黑素替代治疗导致Prl和17β - 雌二醇（E2）水平显著降低，以及乳腺的形态和DNA合成模式改变。在这些动物中给予2 - 溴 - α - 麦角隐亭导致Prl血浆水平显著降低（不影响E2水平），AB密度和DNA合成减少。这些变化损害了乳腺对DMBA的反应性，从乳腺癌发病率的显著降低可以看出。
