Spornitz U M
Anat Embryol (Berl). 1975 May 16;146(3):245-64. doi: 10.1007/BF00302173.
The liver of Xenopus laevis was examined with electron microscopy. Its structure was found to be markedly different from that of mammals, particularly regarding the morphology of the hepatocytes to be classified as typical. It was established that the main function of such a cell is the storage of glycogen, and further that it possesses only scant organelles and other inclusions. Since this type of cell was found most frequently in the liver of untreated animals, it was designated as normal cell. The fact appears noteworthy that in the normal liver of Xenopus laevis an abundance of cell types occur which are otherwise found to be proliferated under experimental conditions, e.g. cells with pronouncedly augmented RER, enlarged Golgi complexes, increased lipid inclusions etc. This high number of divergent hepatocytes and the fact that all intermediate stages between the individual extremes are present and not to be accounted for by the position of the cell within the liver was interpreted as being the expression of a cyclic passage of the various stages of activity. It is of special interest that augmented degradation of glycogen in the liver cell takes place only during vitellogenesis. Acute and chronic hunger, as well as adaptation to cold, hardly affect the morphology of the normal cell, especially as far as the glycogen is concerned. The possible causes for this are discussed.
用电子显微镜对非洲爪蟾的肝脏进行了检查。发现其结构与哺乳动物的结构明显不同，特别是在被归类为典型肝细胞的形态方面。已确定这种细胞的主要功能是储存糖原，并且进一步发现它仅拥有少量的细胞器和其他内含物。由于这种类型的细胞在未处理动物的肝脏中最常被发现，因此被指定为正常细胞。值得注意的是，在非洲爪蟾的正常肝脏中存在大量的细胞类型，而这些细胞类型在实验条件下会增殖，例如粗面内质网明显增加、高尔基体增大、脂质内含物增加等的细胞。这种大量不同的肝细胞以及各个极端之间所有中间阶段都存在且不能由细胞在肝脏中的位置来解释的事实，被解释为各种活动阶段循环过程的表现。特别有趣的是，肝细胞中糖原的降解增加仅在卵黄发生期间发生。急性和慢性饥饿以及对寒冷的适应几乎不影响正常细胞的形态，尤其是就糖原而言。讨论了其可能的原因。
