Purnell D M, Stowers D J
J Natl Cancer Inst. 1978 Nov;61(5):1339-46. doi: 10.1093/jnci/61.5.1339.
Spontaneous mammary hyperplastic alveolar noduligenesis was studied in nulliparous female LEW/Mai rats in relation to age, estrous cycle status, and mammary gland mitotic activity. The morphometric composition of the mammary gland and the incidence of hyperplastic alveolar nodules (HAN) and dysplasias were determined by examination of stained wholemount preparations of one of the inguinal mammary glands. Mitotic activity in the contralateral mammary gland rose almost linearly from 30 to 108 days of age and then fell progressively thereafter, although mitotic activity remained significantly elevated compared to that in mammary glands of rats less than 100 days old. Mitotic activity was nonrandomly distributed in the mammary glands of young pubertal rats in contrast to that in glands of prepubertal rats and in rats in persistent estrus, in which it tended to be randomly distributed. HAN were present in some rats by 150 days of age and were frequent in the mammary glands of most rats older than 200 days. All animals with HAN were in persistent vaginal estrus and had significantly increased pituitary weights. This association suggested that hormone imbalance may be an important etiologic factor in spontaneous hyperplastic alveolar noduligenesis in the rat.
对未生育的雌性LEW/Mai大鼠的自发性乳腺增生性肺泡结节形成进行了研究，涉及年龄、发情周期状态和乳腺有丝分裂活性。通过检查一侧腹股沟乳腺的染色全层标本，确定乳腺的形态计量组成以及增生性肺泡结节（HAN）和发育异常的发生率。对侧乳腺的有丝分裂活性在30至108日龄时几乎呈线性上升，此后逐渐下降，尽管与小于100日龄大鼠的乳腺相比，有丝分裂活性仍显著升高。与青春期前大鼠和持续发情大鼠的乳腺不同，青春期幼鼠乳腺中的有丝分裂活性分布并非随机，后者往往呈随机分布。到150日龄时，一些大鼠出现了HAN，在大多数200日龄以上大鼠的乳腺中很常见。所有患有HAN的动物均处于持续性阴道发情期，垂体重量显著增加。这种关联表明，激素失衡可能是大鼠自发性增生性肺泡结节形成的一个重要病因。
