Removal of basement membrane in the involuting breast.
Removal of basement membrane in the involuting breast.
复制标题
去除复旧乳房的基底膜。
DOI：
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发表时间：
1976
期刊：
影响因子：
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通讯作者：
Pierce Gb
中科院分区：
文献类型：
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作者：
A. Martinez‐Hernandez;Fink Lm;Pierce Gb
通过光学和电子显微镜进行的形态学和免疫组织化学研究表明，在小鼠乳房复旧过程中，基底膜被去除。断奶后第 2 天开始去除基底膜，第 4 天达到最大，并且与上皮细胞的退化相关。没有基底膜吞噬作用的证据，因此该抗原的去除归因于酶水解。为了测定乳腺匀浆对特定基底膜抗原的活性，将包埋在琼脂糖凝胶中的不溶性基底膜与乳腺肝和肾匀浆一起孵育。当用特异性抗体证明基底膜抗原时，发现乳腺匀浆溶解基底膜，但肝脏和肾脏不能溶解基底膜。为了量化反应并确定相关酶的一些特征，用 125I 标记不溶性基底膜，并在与退化乳房提取物一起孵育后将放射性释放到上清液中，表明基底膜发生水解。如果通过先前的洗涤去除天然存在的抑制剂，则乳腺匀浆提取物会广泛水解标记的基底膜，而以类似方式制备的肝脏或肾脏提取物则缺乏活性。基底膜的水解具有时间和浓度依赖性，并且具有最适pH值。通过预先将提取物在100℃下加热30分钟，去除二价阳离子，并存在氟磷酸二异丙酯（一种特定的丝氨酸酯酶抑制剂）来阻断反应；长时间透析未能消除水解活性。结论是，复旧乳房中存在的酶系统能够水解基底膜
Morphologic and immunohistochemical studies by light and electron microscopy indicated that basement membrane was removed during the process of involution of the murine breast. Removal of the basement membrane started 2 days postweaning, was maximal at 4 days, and correlated with degeneration of epithelial cells. There was no evidence of phagocytosis of basement membrane, so the removal of this antigen was attributed to enzymatic hydrolysis. To determine the activity of breast homogenate on the specific basement membrane antigen, insoluble basement membrane embedded in agarose gels was incubated with breast liver and kidney homogenates. When basement membrane antigen was demonstrated by the specific antibody, it was found that breast homogenate solubilized basement membrane but liver and kidney failed to solubilize basement membrane. To quantify the reaction and determine some of the characteristics of the responsible enzyme(s), insoluble basement membrane was labeled with 125I and the release of radioactivity into the supernatant following incubation with extracts of involuting breast indicated hydrolysis of basement membrane. Extracts of breast homogenate extensively hydrolyzed labeled basement membrane if naturally occurring inhibitors were removed by previous washing, whereas liver or kidney extracts prepared in a similar manner were devoid of activity. The hydrolysis of basement membrane was time and concentration dependent and had a pH optimum. The reaction was blocked by prior heating of the extract at 100 degrees C. for 30 minutes, removal of divalent cations, and presence of diisopropylfluorophosphate (a specific serine esterase inhibitor); prolonged dialysis failed to remove the hydrolytic activity. It is concluded that an enzyme system present in the involuting breast is capable of basement membrane hydrolysis