Regulation of animal cell differentiation by food constituent.

为了阐明影响分化的因素及其功能，我们选择了两个细胞系作为模型系统。结果表明，IEC-18细胞是肠上皮干细胞分化的模型细胞。在成年大鼠小肠酸提取物中发现了一种体外诱导肠上皮细胞系分化的因子。在IEC-18细胞培养液中加入部分纯化的大鼠小肠乙酸提取物可在48小时内提高蔗糖酶活性。胸苷掺入在24小时内明显减少。与对照组相比，酸提取物处理的IEC-18细胞微绒毛样结构显著发育。该酸提取物热稳定，表观分子量在400 ~ 800之间。提示该因子可能与大鼠小肠隐窝细胞的上皮分化有关。小鼠成纤维细胞3T3-L1在培养中由前脂肪细胞向脂肪细胞分化。系统比较了20种维生素及其类似物对3T3-L1细胞前脂肪细胞生长速度和前脂肪细胞向脂肪细胞终末分化的影响；维生素C的添加显著提高了50ma以上前脂肪细胞的生长速度。维生素K_3的添加减缓了生长速度，在0.1 ma以上。在水溶性维生素及其类似物中，维生素B_6组和维生素C显著促进了细胞分化，从而增加了甘油磷酸酯脱氢酶活性和甘油三酯积累，其浓度超过10muM。“许多脂溶性”维生素及其类似物（维生素A组，包括β -胡萝卜素、维生素D组、维生素E和维生素K组）在muM水平上强烈抑制3T3-L1细胞的脂肪转化。

In order to clarify factors and their function to differentiation, two cell lines have been selected as model systems.It was shown that IEC-18 cells were model of stem cell of intestinal epithelial differentiation. A factor which may induce differentiation of intestinal epithelial cell lines in vitro was found in an acid extract of adult rat small intestine. The addition of a partially purified acetic acid extract of rat small intestine to IEC-18 cell culture dishes increased sucrase activity within 48 hrs. Thymidine incorporation markedly decreased within 24 hrs. Significant development of microvilli-like structures was observed on the acid extract-treated IEC-18 cells, compared with controls. This activity of tat acid extract was heat-stable and the apparent molecular weight of the factor was 400-800. These findings suggested that the factor may be related to the epithelial differentiation of rat small intestinal crypt cells.Murine fibroblast 3T3-L1 cells differentiate from preadipocytes to adipocytes in culture. The effects of 20 kinds of vitamins or their analogues on the growth rate of preadipocytes and the terminal differentiation of preadipocytes to adipocytes were systematically compared in 3T3-L1 cells; The addition of vitamin C markedly increased the growth rate of preadipocytes at over 50muM. The addition of vitamin K_3 slowed down the growth rate at over 0.1muM. In water soluble vitamins and their analogues tested, the vitamin B_6 group and vitamin C significantly stimulated the differentiation, and consequently increased the glycerophosphate dehydrogenase activity and triglyceride accumulation, to a concentration over 10muM. "Many fat"soluble vitamins and their analogues (the vitamin A group, including beta-carotene, the vitamin D group, vitamin E and vitamin K group) strongly inhibited the adipose conversion of 3T3-L1 cells at muM level.