Bani G, Bigazzi M, Bani D
J Endocrinol Invest. 1986 Apr;9(2):145-52. doi: 10.1007/BF03348086.
The study deals with the effects of relaxin (RLX) on epithelial cells of the mammary ducts in ovariectomized virgin mice, evaluated by light and electron microscopy. One microgram (3 GPU) pure porcine RLX (NIH-RXN-P1) was administered either alone or after pretreatment with estrogen. The possibility of a non specific binding of RLX to insulin receptors on the mammary epithelial cells was excluded by comparing the effects of the administration of the two hormones at the same doses. Our findings indicate that RLX greatly enhances the growth of the mammary duct epithelial cells, as demonstrated by the extensive branching and elongation of the ducts, and by the rather frequent occurrence of mitoses in the epithelial cell precursors and of the intermediate stages of their differentiation into mature duct cells. Three GPU RLX, administered alone, had only an inconstant and slight effect on the epithelial cell growth, a priming dose with estrogen being necessary to obtain the highest levels of duct growth. Moreover the treatment with 1 microgram of insulin for the same time showed a very inconstant and lesser effect in comparison to RLX. We did not find any evidence of alveolar maturation and milk secretion in the RLX-treated mice. The recognition of a stimulatory role of RLX on the proliferation and growth of the mammary duct epithelium may be of a certain importance in the understanding of hormonal control of the mammary development in physiological conditions and the genesis and growth of mammary neoplasms.
本研究通过光学显微镜和电子显微镜评估了松弛素（RLX）对去卵巢处女小鼠乳腺导管上皮细胞的影响。单独或在雌激素预处理后给予1微克（3个豚鼠单位）纯猪松弛素（NIH-RXN-P1）。通过比较相同剂量的两种激素给药效果，排除了RLX与乳腺上皮细胞上胰岛素受体非特异性结合的可能性。我们的研究结果表明，RLX极大地促进了乳腺导管上皮细胞的生长，表现为导管广泛分支和延长，以及上皮细胞前体中频繁出现有丝分裂及其分化为成熟导管细胞的中间阶段。单独给予3个豚鼠单位的RLX对上皮细胞生长仅有不稳定且轻微的影响，需要用雌激素进行预刺激剂量才能获得最高水平导管生长。此外，同时用1微克胰岛素治疗与RLX相比，显示出非常不稳定且较小的效果。在接受RLX治疗的小鼠中，我们未发现任何肺泡成熟和乳汁分泌的证据。认识到RLX对乳腺导管上皮细胞增殖和生长的刺激作用，对于理解生理条件下乳腺发育的激素控制以及乳腺肿瘤的发生和生长可能具有一定重要性。
