Bolshakova L S, Lisitsyn A B, Chernukha I M, Zubtsov Yu N, Lukin D E, Lyublinsky S L
Orel State University of Economics and Trade.
V.M. Gorbatov Federal Research Center for Food Systems, Moscow.
Vopr Pitan. 2018;87(3):12-17. doi: 10.24411/0042-8833-2018-10037. Epub 2018 May 11.
In the course of evolution in animals and humans, a complex and effective system for providing the body with iodine in the form of various organic and inorganic compounds was developed. The metabolism of inorganic iodine has been studied quite well, in contrast to the mechanism of assimilation of its organic compounds. Among the latter, iodotyrosines, which are part of iodinated milk proteins, are of particular interest. To distinguish the peculiarities of the biotransformation of iodotyrosines in the animals' organism, their concentration and the concentration of tyrosine in blood plasma of rats after single administration of iodinated milk proteins were determined. For comparison, in parallel a group of animals received potassium iodide. The tested preparations were administered intragastrically with a probe in the form of aqueous solutions at a dose equivalent to 30 μg iodine per 1 kg of body weight. The level of mono- and diiodotyrosine in rat blood plasma was determined by HPLC with a mass spectrometer detector. The tyrosine content was determined on an automatic amino acid analyzer. The registration of the indices was carried out before the administration and 1, 4 and 24 hours after the administration of the substances. In the course of the conducted studies it was found that when iodinated milk proteins are once administered, a significant increase in the concentrations of monoiodotyrosine and diiodotyrosine is observed. The maximum level of iodinated amino acids, exceeding the control values by more than 6 fold, was recorded 4 hours after the ingestion of iodine-containing organic compounds into the body. At the same time interval, an increase in the concentration of tyrosine was observed in one of the experimental groups receiving iodinated milk protein. The simultaneous presence of tyrosine and its iodinated derivatives in blood plasma may indicate that monoiodotyrosine and diiodotyrosine are capable of being absorbed into the systemic bloodstream without metabolic transformations in the liver. Under introduction of potassium iodide, an increase in blood plasma concentration of monoiodotyrosine by 35% compared to the control was observed only after 24 hours, which may be a consequence of the activation of the thyroid gland due to the intake of an increased amount of iodine.
在动物和人类的进化过程中，形成了一个复杂而有效的系统，以各种有机和无机化合物的形式为身体提供碘。与有机碘化合物的同化机制相比，无机碘的代谢已得到相当充分的研究。在后者中，作为碘化乳蛋白一部分的碘酪氨酸特别令人感兴趣。为了区分碘酪氨酸在动物体内生物转化的特点，测定了单次给予碘化乳蛋白后大鼠血浆中碘酪氨酸的浓度以及酪氨酸的浓度。为作比较，同时有一组动物接受碘化钾。受试制剂以水溶液形式通过探针经胃内给药，剂量相当于每1千克体重30微克碘。大鼠血浆中一碘酪氨酸和二碘酪氨酸的水平用带质谱检测器的高效液相色谱法测定。酪氨酸含量用自动氨基酸分析仪测定。在给予物质前以及给予物质后1小时、4小时和24小时记录各项指标。在进行的研究过程中发现，单次给予碘化乳蛋白时，可观察到一碘酪氨酸和二碘酪氨酸的浓度显著增加。摄入含碘有机化合物进入体内4小时后，碘化氨基酸的最高水平超过对照值6倍以上。在同一时间间隔，接受碘化乳蛋白的一个实验组中观察到酪氨酸浓度增加。血浆中同时存在酪氨酸及其碘化衍生物可能表明一碘酪氨酸和二碘酪氨酸能够在不经肝脏代谢转化的情况下被吸收进入体循环。给予碘化钾后，仅在24小时后观察到血浆中一碘酪氨酸的浓度比对照增加35%，这可能是由于摄入增加量的碘导致甲状腺激活的结果。
