Individual and combined effects of relaxin, estrogen, and progesterone in ovariectomized gilts. II. Effects on mammary development.
Individual and combined effects of relaxin, estrogen, and progesterone in ovariectomized gilts. II. Effects on mammary development.
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DOI：
10.1210/endo.135.3.8070370
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发表时间：
1994-09
期刊：
影响因子：
4.8
通讯作者：
R. Winn;M. Baker;C. Merle;O. Sherwood
中科院分区：
文献类型：
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作者：
R. Winn;M. Baker;C. Merle;O. Sherwood
后备母猪在 115 天妊娠期的最后三分之一期间，乳腺实质（导管、小叶和肺泡）显着发育。乳腺的这些变化在时间上与血液中松弛素、雌激素和黄体酮水平升高相关。我们最近证明，松弛素在促进怀孕后备母猪乳腺实质发育方面发挥着重要作用。雌激素和黄体酮在后备母猪乳腺中的作用仍然知之甚少。因此，本研究确定了松弛素、雌激素和黄体酮单独或组合对乳房发育的影响。卵巢切除术后十五天，将六至八只非妊娠性成熟后备母猪分配至以下八个治疗组之一：卵巢切除对照组、松弛素治疗组、雌激素治疗组、黄体酮治疗组、雌激素加松弛素治疗组、孕酮加松弛素治疗组、雌激素加孕酮治疗组和黄体酮加雌激素加松弛素治疗组。治疗持续 10 天，选择剂量的松弛素（0.5 毫克，每天四次）、苯甲酸雌二醇（1 毫克，每天两次）和黄体酮（50 毫克，每天两次），以提供与妊娠第 100-110 天之间出现的血液水平相似的水平。收集前端的第四个乳腺。实质组织的横截面积用于测量实质发育的程度。为了更详细地检查乳腺实质发育，使用形态测量分析进行激素治疗对小叶-肺泡发育的影响。单独的松弛素对乳腺发育几乎没有影响，单独的雌激素仅适度地刺激乳腺发育。相反，雌激素和松弛素联合治疗可显着刺激乳腺发育。单独使用黄体酮对小叶-肺泡发育没有影响，但令人惊讶的是，当与松弛素联合施用时，黄体酮减少了乳腺基质的胶原纤维的组织。总之，这项研究与最近的报道一致，即松弛素在后备母猪乳腺发育中发挥着重要作用。此外，它表明松弛素与雌激素协同作用，刺激乳腺实质的发育。最后，这项研究表明，松弛素与黄体酮协同作用会降低生长中乳腺周围胶原蛋白基质的组织。这项研究与松弛素、雌激素和黄体酮很可能在后备母猪乳腺发育中发挥作用的观点是一致的。
Marked development of the mammary parenchyma (ducts, lobules, and alveoli) occurs during the last third of the 115-day gestation period in the gilt. These changes in the mammary gland are temporally correlated with elevated blood levels of relaxin, estrogen, and progesterone. We recently demonstrated that relaxin plays a major role in promoting the development of the mammary parenchyma that occurs in pregnant gilts. The roles of estrogen and progesterone in the mammary gland in gilts remain poorly understood. Accordingly, this study determined the influence of relaxin, estrogen, and progesterone, individually and in combination, on mammary development. Fifteen days after ovariectomy, six to eight nonpregnant sexually mature gilts were assigned to one of the following eight treatment groups: ovariectomized controls, relaxin treated, estrogen treated, progesterone-treated, estrogen plus relaxin treated, progesterone plus relaxin treated, estrogen plus progesterone treated and progesterone plus estrogen plus relaxin treated. Treatment was given for 10 days, with doses of relaxin (0.5 mg, four times daily), estradiol benzoate (1 mg, twice daily), and progesterone (50 mg, twice daily) selected to provide blood levels similar to those occurring between days 100-110 of gestation. The fourth mammary gland from the anterior end was collected. The cross-sectional area of the parenchymal tissue was used to measure the extent of parenchymal development. To examine mammary parenchymal development in more detail, the effect of hormone treatment on lobulo-alveolar development was conducted using morphometric analysis. Relaxin alone had little effect on mammary development, and estrogen alone stimulated mammary development only modestly. In contrast, combined treatment with estrogen and relaxin stimulated mammary development markedly. Progesterone alone had no effect on lobulo-alveolar development, but, surprisingly, when administered in combination with relaxin, progesterone reduced the organization of the collagen fibrils of the mammary stroma. In conclusion, this study is consistent with recent reports that relaxin plays an important role in the development of the mammary gland in gilts. Moreover, it demonstrates that relaxin acts in concert with estrogen to stimulate development of the mammary parenchyma. Finally, this study demonstrates that relaxin in concert with progesterone decreases the organization of the collagen matrix surrounding the growing mammary gland. This study is consistent with the view that relaxin, estrogen, and progesterone all very likely play roles in the development of the mammary gland in gilts.