Quirk P G, King G F, Campbell I D, Boyd C A
Department of Human Anatomy, University of Oxford, United Kingdom.
Am J Physiol. 1989 Feb;256(2 Pt 1):G423-9. doi: 10.1152/ajpgi.1989.256.2.G423.
Isolated enterocytes prepared from chicken small intestine were studied by proton nuclear magnetic resonance (NMR). Perchloric acid extracts of cells were prepared from duodenum, jejunum, and ileum, and concentrations of 19 different metabolites were determined after the virtually complete assignment of all peaks in the aliphatic region of the spectrum. High concentrations of serine ethanolamine phosphodiester (SEP), creatine, taurine, and acidic amino acids were found in all segment extracts. Relatively high concentrations of SEP (approximately 12 mM) and acidic amino acids (approximately 3.5 mM) were found in the ileum, whereas creatine (3 mM) and lactate (6.5 mM) were found at higher concentrations in jejunum. Taurine (approximately 8 mM), choline (0.5 mM), and betaine (approximately 0.5 mM) were evenly distributed throughout the segments. Fasting (40 h) led to substantial increases in the concentrations of pyruvate, succinate, SEP, and taurine, while neutral hydrophobic amino acid concentrations fell appreciably. The significance of the findings is discussed, and the possible contributions of SEP, taurine, and choline to membrane lipid homeostasis are considered.
采用质子核磁共振（NMR）技术对从鸡小肠制备的离体肠上皮细胞进行了研究。从十二指肠、空肠和回肠制备细胞的高氯酸提取物，并在光谱脂肪族区域所有峰几乎完全归属后，测定了19种不同代谢物的浓度。在所有节段提取物中均发现高浓度的丝氨酸乙醇胺磷酸二酯（SEP）、肌酸、牛磺酸和酸性氨基酸。在回肠中发现相对较高浓度的SEP（约12 mM）和酸性氨基酸（约3.5 mM），而在空肠中发现肌酸（3 mM）和乳酸（6.5 mM）浓度较高。牛磺酸（约8 mM）、胆碱（0.5 mM）和甜菜碱（约0.5 mM）在各节段中分布均匀。禁食（40小时）导致丙酮酸、琥珀酸、SEP和牛磺酸浓度大幅增加，而中性疏水氨基酸浓度明显下降。讨论了这些发现的意义，并考虑了SEP、牛磺酸和胆碱对膜脂稳态的可能贡献。
