Davis A T
Department of Surgery, Michigan State University, Grand Rapids.
J Nutr. 1989 Feb;119(2):262-7. doi: 10.1093/jn/119.2.262.
This study was designed to determine the fraction of tissue total carnitine derived from the mother in utero, from milk, and from fetal and neonatal de novo synthesis. Female rats were offered drinking water ad libitum containing either tritium or [14C]-labeled carnitine (0.1 mCi/mmol, 5 mM). The rats were mated, and after birth, the pups of females given the tritium-labeled water were switched with the pups of rats given the [14C]-labeled carnitine (cross-fostering). Analyses of neonatal tissue total carnitine in five tissues were determined on d 0, 1, 2, 5, 10, and 20 after birth. Carnitine derived from neonatal de novo synthesis remained relatively constant from birth throughout the 20 d period, ranging from 26% in liver to 50% in the heart at d 0. The contribution from milk carnitine rose rapidly after birth until d 5, at which time it became relatively constant, ranging from 40.8% in heart to 55.4% in kidney at d 20. The fetus is a major contributor to its own tissue carnitine. Nevertheless, the infant rat is dependent upon external sources of carnitine in order to maintain tissue carnitine levels.
本研究旨在确定组织总肉碱中源自子宫内母体、乳汁以及胎儿和新生儿从头合成的部分。给雌性大鼠随意提供含有氚或[14C]标记肉碱（0.1 mCi/mmol，5 mM）的饮用水。大鼠交配后，出生后，给饮用含氚标记水的雌性大鼠的幼崽与给[14C]标记肉碱的大鼠的幼崽进行交换（交叉寄养）。在出生后的第0、1、2、5、10和20天对五个组织中的新生组织总肉碱进行分析。源自新生儿从头合成的肉碱从出生到整个20天期间相对保持恒定，在第0天时，肝脏中为26%，心脏中为50%。乳汁肉碱的贡献在出生后迅速上升，直到第5天，此时变得相对恒定，在第20天时，心脏中为40.8%，肾脏中为55.4%。胎儿是其自身组织肉碱的主要贡献者。然而，幼鼠依赖外部肉碱来源以维持组织肉碱水平。
