Forssmann W G, Metz J
Cell Tissue Res. 1976 Sep 1;171(4):467-82. doi: 10.1007/BF00220239.
After the application of parachlorophenylalanine (pCPA), an amino acid analogue, paracrystalline inclusions are observed in the exocrine pancreas of the rat. The formation of the paracrystalline structures varies according to the dose and the time of examination. Although the first alterations can be seen in the Golgi apparatus and the condensing vacuoles, the main localization of these structures is within the cisternae of the RER. At the same time as degenerative changes occur in the cells, involving autophagic and heterophagic processes, regeneration also takes place. With the freeze-fracturing method, the paracrystalline inclusions are interpreted as lamellae or plates of probably altered secretory proteins in extremely extended RER-cisternae. The fracture surfaces of the paracrystals show a periodicity of about 80 A running diagnonally to the main axis of the paracrystalline structures, which are mainly oriented from the basal parts of the exocrine pancreatic cells to the cell apices. The mechanism of paracrystalline formation is discussed on the basis of the morphologic results. It could be shown that after pCPA administration the amylase content is decreased concomittantly with degranulation. pCPA seems not to be incorporated into secretory proteins; high intracellular concentrations, however, are required to induce the formation of the paracrystalline structures. This morphological study is the basis for other studies dealing with secretion and intracellular transport in the pancreatic acinar cell under experimental conditions.
在应用对氯苯丙氨酸（pCPA）（一种氨基酸类似物）后，在大鼠的外分泌胰腺中观察到类晶体包涵体。类晶体结构的形成根据剂量和检查时间而有所不同。尽管最初的变化可见于高尔基体和浓缩泡，但这些结构的主要定位是在粗面内质网的池内。在细胞发生涉及自噬和异噬过程的退行性变化的同时，再生也在进行。用冷冻断裂法观察，类晶体包涵体被解释为在极度扩张的粗面内质网池内可能发生改变的分泌蛋白的薄片或板层。类晶体的断裂面显示出约80埃的周期性，与类晶体结构的主轴呈对角线方向，这些结构主要从外分泌胰腺细胞的基部向细胞顶端排列。根据形态学结果讨论了类晶体形成的机制。结果表明，给予pCPA后，淀粉酶含量随着脱粒而降低。pCPA似乎没有掺入分泌蛋白中；然而，需要高细胞内浓度才能诱导类晶体结构的形成。这项形态学研究是其他关于实验条件下胰腺腺泡细胞分泌和细胞内运输研究的基础。
