Fritsch P, Beauvallet M, Jouniaux B, Metivier H, Masse R
Int J Radiat Biol Relat Stud Phys Chem Med. 1986 Oct;50(4):609-20. doi: 10.1080/09553008614551011.
The transfer of soluble Np(V) nitrate was measured in gastrointestinal segments from adult rats by two procedures: instillation, in segments in which the physico-chemical form of Np might be modified by gastrointestinal factors; and perfusion, in segments in which the luminal state of Np remains constant. These assays allowed accurate measurement of the Np(V) transferred from the intestine to the whole body. The amount measured was proportional to segment length and to the duration of the experiments, which lasted for periods of 0.25 to 2 h. Under these experimental conditions, hourly transfer values were about 2 percent, both per millilitre of Np(V) solution instilled and per 10 cm of jejunum perfused. This flux is very much greater than that which may be deduced from studies in which Np was gavaged into intact rats. Intestinal transfer of Np was constant for Np concentrations ranging from 5 X 10(-12) M to 1 X 10-4) M. Raising the concentration of Np(V) to more than 1 X 10(-4) M reduced its intestinal transfer. Addition of Fe(II) also reduced it. The small intestine was the main site of Np(V) absorption, since the transfer from instilled jejunum was about 20 times that observed from the stomach, and no difference was noted between jejunal and duodenal transfer.
通过两种方法测量了成年大鼠胃肠道各段中可溶性硝酸镎（V）的转运情况：一是滴注法，在硝酸镎的物理化学形式可能会被胃肠道因素改变的肠段进行；二是灌注法，在硝酸镎管腔状态保持恒定的肠段进行。这些测定方法能够准确测量从肠道转运至全身的镎（V）量。所测的量与肠段长度和实验持续时间成正比，实验持续时间为0.25至2小时。在这些实验条件下，每小时的转运值约为2%，这一数值对于每毫升滴注的镎（V）溶液和每10厘米灌注的空肠来说是相同的。该通量远大于通过将镎经口灌胃给完整大鼠的研究所推断出的通量。当镎的浓度范围为5×10⁻¹²摩尔/升至1×10⁻⁴摩尔/升时，镎在肠道的转运是恒定的。将镎（V）的浓度提高到超过1×10⁻⁴摩尔/升会降低其在肠道的转运。添加亚铁离子（Fe(II)）也会降低其转运。小肠是镎（V）吸收的主要部位，因为从滴注空肠的转运量约为从胃中观察到的转运量的20倍，并且空肠和十二指肠的转运之间未发现差异。
