Haubrich D R, Gerber N, Pflueger A B, Zweig M
J Neurochem. 1981 Apr;36(4):1409-17. doi: 10.1111/j.1471-4159.1981.tb00580.x.
An enzymatic-radioisotopic assay was used to measure free choline in unextracted tissue. The lowest concentration of free choline in any tissue studied was present in human cerebrospinal fluid (mean, 5.7 microM; range, 1.8 + 31.2 microM). A postmortem increase in concentration of free choline occurred in blood (0.2 nmol/min.ml), kidney (13 nmol/min.g) and liver (22 nmol/min.g) of mice. The concentration of free choline in these tissues was estimated by extrapolation to be 5, 77, and 29 nmol/g (or ml), respectively. Several treatments were found to increase the concentration of free choline. For example, intraperitoneal administration of choline or 2-amino-2-methyl-propanol (a choline oxidase inhibitor) induced an increase in the level of choline i blood, kidneys, liver, and brain of mice, and administration of 2-dimethylaminoethanol (deanol) caused an increase in kidney and liver choline. The level of choline in blood was increased when rats were treated orally with either antibiotics or esters of choline such as phosphorylcholine, glycerylphosphorylcholine, laroylcholine, or propionylcholine. The results show that the concentration of free choline may be regulated by intestinal metabolism, availability of esterified precursors, and activity of enzymes that metabolize choline.
采用酶促放射性同位素分析法测定未提取组织中的游离胆碱。在所研究的任何组织中，游离胆碱的最低浓度存在于人类脑脊液中（平均值为5.7微摩尔/升；范围为1.8 + 31.2微摩尔/升）。小鼠血液（0.2纳摩尔/分钟·毫升）、肾脏（13纳摩尔/分钟·克）和肝脏（22纳摩尔/分钟·克）中的游离胆碱浓度在死后有所增加。通过外推法估计这些组织中游离胆碱的浓度分别为5、77和29纳摩尔/克（或毫升）。发现几种处理方法可增加游离胆碱的浓度。例如，腹腔注射胆碱或2-氨基-2-甲基丙醇（一种胆碱氧化酶抑制剂）可导致小鼠血液、肾脏、肝脏和大脑中的胆碱水平升高，而给予2-二甲基氨基乙醇（二甲胺醇）可使肾脏和肝脏中的胆碱增加。当大鼠口服抗生素或胆碱酯（如磷酸胆碱、甘油磷酸胆碱、月桂酰胆碱或丙酰胆碱）时，血液中的胆碱水平会升高。结果表明，游离胆碱的浓度可能受肠道代谢、酯化前体的可用性以及代谢胆碱的酶活性的调节。
