Tuan R S, Scott W A, Cohn Z A
J Cell Biol. 1978 Jun;77(3):752-61. doi: 10.1083/jcb.77.3.752.
A simple method was devised for the maintenance of the chorioallantoic membrane (CAM) of chick embryos in organ culture. Explants of CAM survived for up to 5 days in this system and retained the characteristic three-layered morphology (ectoderm, mesoderm, and endoderm). Induction of the CAM calcium-binding protein (CaBP) by effectors of calcium metabolism was studied in these organ cultures. Vitamin K was found to elicit a seven- to eightfold increase in CaBP, whereas no increase in CaBP activity occurred on supplementation with vitamin A, parathyroid hormone, an analogue of vitamin D, vitamin D and its hydroxylated metabolites, or with elevated calcium levels. The vitamin K-mediated induction of CaBP was dose-dependent, inhibited by the vitamin K antagonists warfarin and dicoumarol, selective for vitamin K5, and maximal at the developmental stage (13-15 days of incubation) corresponding to the onset of calcium transport by the CAM in vivo. CaBP levels increased after 60-70 h in cultures of 13-15 day CAM supplemented with vitamin K and reached maximal levels around 80-90 h of culture. The CAM ectoderm underwent extensive proliferation and often assumed a villuslike morphology in the vitamin K cultures.
设计了一种在器官培养中维持鸡胚绒毛尿囊膜（CAM）的简单方法。CAM外植体在该系统中存活长达5天，并保留了特征性的三层形态（外胚层、中胚层和内胚层）。在这些器官培养物中研究了钙代谢效应物对CAM钙结合蛋白（CaBP）的诱导作用。发现维生素K可使CaBP增加7至8倍，而补充维生素A、甲状旁腺激素、维生素D类似物、维生素D及其羟基化代谢产物或提高钙水平时，CaBP活性均未增加。维生素K介导的CaBP诱导呈剂量依赖性，受维生素K拮抗剂华法林和双香豆素抑制，对维生素K5具有选择性，且在与CAM体内钙转运开始相对应的发育阶段（孵化13至15天）达到最大值。在补充维生素K的13至15天CAM培养物中，CaBP水平在60至70小时后升高，并在培养80至90小时左右达到最高水平。在维生素K培养物中，CAM外胚层经历了广泛的增殖，并且常常呈现出绒毛状形态。
