Sheard N F, Krasin B
Department of Nutrition, University of Massachusetts, Amherst 01003.
J Nutr. 1994 May;124(5):738-43. doi: 10.1093/jn/124.5.738.
Previous reports in animals indicate that choline deficiency alters carnitine metabolism. Recent studies in humans suggest that choline deficiency occurs in individuals during long term total parenteral nutrition. Malnutrition is also a frequent complication in this population. We therefore examined the effect of restricting the intake of a choline-deficient diet on carnitine concentrations in plasma and tissues. Adult male rats were randomly assigned to one of four dietary regimens: control, choline deficient, restricted control (85% of control), or restricted choline deficient for 42-43 d. At the end of the experimental period, restricted animals weighed significantly less than their respective controls (P < 0.01). Liver weight relative to body weight and fat concentration were greater in choline-deficient animals (P < 0.01 and 0.001, respectively). Choline-deficient rats fed free access had elevated plasma carnitine concentration (P < 0.01). Urinary carnitine excretion was elevated in both groups of choline-deficient rats (P < 0.01), while liver, heart and muscle carnitine concentrations were lower than in controls (P < 0.05). Restricting dietary intake reduced plasma carnitine concentration in choline-deficient animals (P < 0.01), but did not alter tissue or urine carnitine concentrations in either group. Restricted, choline-deficient animals did not exhibit a worsening of the sequelae of choline deficiency. We conclude that choline deficiency alters carnitine concentrations in plasma and tissues and that restricting the intake of a choline-deficient diet does not alter this effect in tissues.
以往动物实验报告表明，胆碱缺乏会改变肉碱代谢。近期人体研究显示，长期接受全胃肠外营养的个体存在胆碱缺乏现象。营养不良也是该人群常见的并发症。因此，我们研究了限制胆碱缺乏饮食摄入量对血浆和组织中肉碱浓度的影响。成年雄性大鼠被随机分为四种饮食方案之一：对照组、胆碱缺乏组、限制对照组（对照组摄入量的85%）或限制胆碱缺乏组，为期42 - 43天。实验期结束时，限制饮食组动物体重显著低于各自的对照组（P < 0.01）。胆碱缺乏组动物肝脏重量与体重的比值及脂肪浓度更高（分别为P < 0.01和0.001）。自由进食的胆碱缺乏大鼠血浆肉碱浓度升高（P < 0.01）。两组胆碱缺乏大鼠的尿肉碱排泄均增加（P < 0.01），而肝脏、心脏和肌肉中的肉碱浓度低于对照组（P < 0.05）。限制饮食摄入量可降低胆碱缺乏组动物的血浆肉碱浓度（P < 0.01），但两组的组织或尿液肉碱浓度均未改变。限制饮食的胆碱缺乏动物并未出现胆碱缺乏后遗症的恶化。我们得出结论，胆碱缺乏会改变血浆和组织中的肉碱浓度，且限制胆碱缺乏饮食的摄入量并不会改变组织中的这种影响。
