Wahab I M, Anderson R R
Department of Dairy Science, University of Missouri, Columbia 65211.
Proc Soc Exp Biol Med. 1989 Dec;192(3):285-9. doi: 10.3181/00379727-192-42999.
The role of relaxin in stimulating growth of the mammary gland was assessed in ovariectomized and intact male rats for a period of 20 days. In addition to relaxin alone, the ovarian mammogenic hormones estradiol and progesterone were used in combination with relaxin and with each other to evaluate responses of mammae. Indices for mammary growth included wet weight, dry fat-free tissue, DNA, RNA, total protein, and collagen. Quantitative estimates of DNA and collagen represented the best indicators of parenchymal and stromal growth, respectively. Because changes in body weights were significantly different among hormonally administered groups, these were included as well. In Ovariectomized young rats, relaxin alone and in combination with estradiol and progesterone increased all indices significantly (P less than 0.01). The collagenous portion of total protein was high for the group receiving relaxin alone (62%) compared with the control group (46%). Relaxin administered along with estradiol and progesterone increased collagen accumulation to 73%, compared with 54% in the estradiol + progesterone group. Relaxin did not significantly increase growth indices when administered to male rats at 10 and 20 micrograms/day, while 30 micrograms stimulated a significant increase in total protein (P less than 0.05), suggesting that 30 micrograms of relaxin/day may be considered the basal concentration needed to induce a physiologic response in males. Relaxin induced a growth effect on mammae by synergizing with progesterone and estradiol in order to stimulate parenchymal proliferation, as noted by a DNA increase, and to increase stromal distensibility of the mammary pad by invoking accumulation of collagen and total protein in substituting for mammary adipose tissue.
在去卵巢和完整雄性大鼠中评估松弛素刺激乳腺生长的作用，为期20天。除了单独使用松弛素外，还将卵巢促乳腺生成激素雌二醇和孕酮与松弛素联合使用以及它们相互组合使用，以评估乳腺的反应。乳腺生长指标包括湿重、无脂干组织、DNA、RNA、总蛋白和胶原蛋白。DNA和胶原蛋白的定量估计分别代表实质和间质生长的最佳指标。由于激素给药组之间体重变化存在显著差异，因此也将体重纳入评估。在去卵巢的幼鼠中，单独使用松弛素以及与雌二醇和孕酮联合使用均显著增加了所有指标（P<0.01）。与对照组（46%）相比，单独接受松弛素的组总蛋白中的胶原蛋白部分较高（62%）。与雌二醇+孕酮组的54%相比，松弛素与雌二醇和孕酮一起给药可使胶原蛋白积累增加至73%。当以每天10微克和20微克的剂量给雄性大鼠注射松弛素时，松弛素并未显著增加生长指标，而30微克则刺激总蛋白显著增加（P<0.05），这表明每天30微克的松弛素可能被认为是在雄性大鼠中诱导生理反应所需的基础浓度。如DNA增加所示，松弛素通过与孕酮和雌二醇协同作用来诱导乳腺生长效应，以刺激实质细胞增殖，并通过促使胶原蛋白和总蛋白积累以替代乳腺脂肪组织来增加乳腺垫的间质伸展性。
