Studies on physiological function of nutrients using model of cell differenciation

为了阐明营养物质的生理功能，选择了两个细胞系作为模型系统。胚胎癌F9是一个有趣的克隆细胞系，因为它的分化是由维甲酸产生的。以层粘连蛋白的生物合成和分泌为标记物，研究维甲酸和cAMP对F9细胞分化的影响。与维甲酸的不可逆作用相反，cAMP对F9分化的作用是可逆的。阐明了F9细胞层粘连蛋白亚单位的翻译后组装和糖基化的机制。提示不同浓度范围的维甲酸可诱导F9干细胞分化为两种类型的细胞，小鼠成纤维细胞3T1-L1细胞在培养过程中具有向前脂肪细胞分化的能力。比较儿茶酚胺对3T3-L1前脂肪细胞和脂肪细胞内源性蛋白质磷酸化的影响。仅在3T3-L1脂肪细胞中观察到分子量为90,000、62,000、48,000和32,000的蛋白质被刺激的磷酸化。加入去甲肾上腺素后1min，可观察到3T3-L1中62000Dalton蛋白的磷酸化；加入心得安后，10min内可观察到去磷酸化。诱导剂(地塞米松、1-甲基-3-异丁基黄嘌呤和胰岛素)刺激的3To-L1细胞的脂肪转化可被LiCl2~20 mM抑制。氯化锂的作用是可逆的。

In order to clarify physiological function of nutrients, two cell lines have been selected as model systems.Embryonal carcinoma F9 is an interesting clonal cell line because its differenciation is generated by retinoic acid. The effect of retinoic acid and cAMP on the differenciation of F9 cells were studied mainly using the biosynthesis and secretion of laminin as markers. In contrast to the irreversible effect of retinoic acid, the effect of cAMP on F9 differenciation was reversible. Michanisms of post-translational assembly and glycosylation of laminin subunits in F9 cells were clarified. It was suggested that different concentration range of retinoic acid induced differenciation of F9 stem cells into two type cells.Murine fibroblast 3T1-L1 cells have capability to differenciate from preadipocytes into adipocytes in culture. The endogenous protein phosphorylation stimulated by catecholamines was compared in 3T3-L1 preadipocytes and adipocytes. Stimulated phosphorylation of proteins with molecular weight 90,000, 62,000, 48,000 and 32,000 was observed only in 3T3-L1 adipocytes. The phosphorylation of the 62,000 dalton protein in 3T3-L1 was observed 1 min after the addition of norepinephrine and dephosphorylation was observed within 10 min after the addition of propranolol. Inducer (dexamethasone, 1-methyl-3-isobutylxanthine and insulin)-stimulated adipose conversion of 3To-L1 cells was inhibited by LiCl at concentrations ranzing from 2 to 20 mM. Effect of LiCl was reversible.