Dylewski D P, Keenan T W
Cytobios. 1984;39(155-156):191-206.
Aspects of the apparent origin, maturation, and secretion of proteins in mammary epithelial cells of the pregnant rat were investigated using standard transmission electron microscopy. Epithelial cells from prelactating animals, sacrificed at intervals up to 1 day ante partum, contained protein-filled vesicles which appeared to arise from two separate intracellular sources, (1) Golgi apparatus dictyosomes, and (2) dilated cisternae of rough endoplasmic reticulum. Vesicles which appeared to originate in the Golgi apparatus were small (means = 0.28 micron diameter), contained a single protein particle, and appeared to release their content exocytotically into the lumen. Vesicles which appeared to originate in the endoplasmic reticulum were larger (means = 3.2 micron diameter), contained numerous protein particles, and appeared to be released from cells with their outer membrane. Post-exocytotic endoplasmic reticulum-derived vesicles in alveolar lumina appeared to be the 'nuclei' of structures previously described as colostrum cells or corpuscles of Donn é. Results from quantitative ultrastructural analysis of mammary tissue from pregnant animals suggested that the intracellular disposal mechanism for turnover of secretory protein may not be of major importance.
利用标准透射电子显微镜对妊娠大鼠乳腺上皮细胞中蛋白质的明显起源、成熟和分泌方面进行了研究。在产前1天内的不同时间点处死泌乳前期动物，其上皮细胞含有充满蛋白质的囊泡，这些囊泡似乎来自两个不同的细胞内来源：（1）高尔基体的扁平囊泡，以及（2）粗面内质网的扩张池。似乎起源于高尔基体的囊泡较小（平均直径=0.28微米），含有单个蛋白质颗粒，并且似乎通过胞吐作用将其内容物释放到管腔中。似乎起源于内质网的囊泡较大（平均直径=3.2微米），含有许多蛋白质颗粒，并且似乎带着其外膜从细胞中释放出来。肺泡腔中内质网来源的囊泡在胞吐后似乎是先前描述为初乳细胞或多内小体的结构的“核心”。对妊娠动物乳腺组织的定量超微结构分析结果表明，分泌蛋白周转的细胞内处理机制可能不太重要。
