Lead, isotope of mass 210 | 14255-04-0

• 分子结构分类: 无机化合物 - 均相金属化合物 - 均相后过渡金属化合物
• 英文名称: Lead, isotope of mass 210
• 英文别名: lead-210
• CAS: 14255-04-0
• 化学式: Pb
• 分子量: 209.98419
• InChiKey: WABPQHHGFIMREM-AKLPVKDBSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  -0.38
• 重原子数：
  1
• 可旋转键数：
  0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.0
• 拓扑面积：
  0
• 氢给体数：
  0
• 氢受体数：
  0

ADMET

代谢

铅通过吸入、口服和皮肤接触被吸收，然后主要分布到骨骼和红细胞中。在血液中，铅可能被发现与血清白蛋白或金属结合蛋白金属lothionein结合。有机铅通过细胞色素P-450酶代谢，而无机铅与δ-氨基酮酸脱氢酶形成复合物。铅主要通过尿液和粪便排出。(L136)

Lead is absorbed following inhalation, oral, and dermal exposure. It is then distributed mainly to the bones and red blood cells. In the blood lead may be found bound to serum albumin or the metal-binding protein metallothionein. Organic lead is metabolized by cytochrome P-450 enzymes, whereas inorganic lead forms complexes with delta-aminolevulinic acid dehydratase. Lead is excreted mainly in the urine and faeces. (L136)

来源:Toxin and Toxin Target Database (T3DB)

毒理性

• 毒性总结

铅模仿其他生物学上重要的金属，如锌、钙和铁，作为许多它们各自酶促反应的辅因子与之竞争。例如，铅已被证明通过竞争性抑制钙与钙调蛋白的结合，干扰神经递质的释放。它对NMDA受体和蛋白激酶C表现出类似的竞争性抑制，这损害了大脑微血管的形成和功能，并改变了血脑屏障。铅还通过影响多巴胺合成的调节和阻止乙酰胆碱的诱发释放来影响神经系统。然而，铅的主要作用机制是通过抑制δ-氨基-戊酸脱水酶，这是生物合成血红素的关键酶，而血红素是血红蛋白必需的辅因子。铅-210产生的电离辐射导致细胞损伤，包括DNA断裂、准确或不准确的修复、凋亡、基因突变、染色体改变和遗传不稳定。这导致正常细胞和组织的动态平衡丧失，并发展为恶性肿瘤。不直接损害DNA的电离辐射可以产生反应性氧中间体，直接影响细胞周期调节中重要的酶p53的稳定性，并通过DNA复制期间的错配导致DNA单个碱基的氧化损伤和点突变。(L1837, T4, A20, A22, L136)

Lead mimics other biologically important metals, such as zinc, calcium, and iron, competing as cofactors for many of their respective enzymatic reactions. For example, lead has been shown to competitively inhibit calcium's binding of calmodulin, interferring with neurotransmitter release. It exhibits similar competitive inhibition at the NMDA receptor and protein kinase C, which impairs brain microvascular formation and function, as well as alters the blood-brain barrier. Lead also affects the nervous system by impairing regulation of dopamine synthesis and blocking evoked release of acetylcholine. However, it's main mechanism of action occurs by inhibiting delta-aminolevulinic acid dehydratase, an enzyme vital in the biosynthesis of heme, which is a necesssary cofactor of hemoglobin. The ionizing radiation produced by lead-210 causes cellular damage that includes DNA breakage, accurate or inaccurate repair, apoptosis, gene mutations, chromosomal change, and genetic instability. This leads to loss of normal cell and tissue homeostasis, and development of malignancy. Ionizing radiation that does not directly damage DNA can produce reactive oxygen intermediates that directly affect the stability of p53, an important enzyme in cell-cycle regulation, and produce oxidative damage to individual bases in DNA and point mutations by mispairing during DNA replication. (L1837, T4, A20, A22, L136)

来源:Toxin and Toxin Target Database (T3DB)

毒理性

• 致癌物分类

内化的发射β粒子的放射性核素对人类是致癌的（第1组）（L2150）。铅-210主要通过β衰变。

Internalized radionuclides that emit β particles are carcinogenic to humans (Group 1) (L2150). Lead-210 primarily undergoes beta decay.

来源:Toxin and Toxin Target Database (T3DB)

毒理性

• 健康影响

铅是一种神经毒素，已知会导致大脑损伤和认知能力下降，特别是在儿童中。铅暴露可能导致肾病，以及如高血压和贫血等血液疾病。铅还表现出生殖毒性，可能导致流产和减少精子产生。由于铅-210具有放射性，它还可能引起癌症。

Lead is a neurotoxin and has been known to cause brain damage and reduced cognitive capacity, especially in children. Lead exposure can result in nephropathy, as well as blood disorders such as high blood pressure and anemia. Lead also exhibits reproductive toxicity and can results in miscarriages and reduced sperm production. As lead-210 is radioactive, it can cause cancer. (L21)

来源:Toxin and Toxin Target Database (T3DB)

毒理性

• 暴露途径

口服（L136）；吸入（L136）；皮肤给药（L136）

Oral (L136) ; inhalation (L136) ; dermal (L136)

来源:Toxin and Toxin Target Database (T3DB)

毒理性

• 症状

慢性铅中毒的症状包括认知能力下降、恶心、腹痛、易怒、失眠、口中金属味、过度乏力或过度活跃、胸痛、头痛，在极端情况下还可能发生癫痫、昏迷和死亡。此外，还可能伴有胃肠道问题，如便秘、腹泻、呕吐、食欲不振、体重减轻，这些在急性中毒中较为常见。暴露在高剂量的电离辐射下会导致急性辐射综合症，可能造成皮肤烧伤、脱发、恶心、呕吐、眩晕、定向障碍、低血压、头痛、疲劳、虚弱、发热、出生缺陷、疾病、感染和死亡。（L1837, L1852, A2, L21）

Symptoms of chronic lead poisoning include reduced cognitive abilities, nausea, abdominal pain, irritability, insomnia, metal taste in the mouth, excess lethargy or hyperactivity, chest pain, headache and, in extreme cases, seizures, coma, and death. There are also associated gastrointestinal problems, such as constipation, diarrhea, vomiting, poor appetite, weight loss, which are common in acute poisoning. Exposure to high doses of ionizing radiation results in acute radiation syndrome, which can cause skin burns, hair loss, nausea, vomiting, dizziness, disorientation, low blood pressure, headache, fatigue, weakness, fever, birth defects, illness, infection, and death. (L1837, L1852, A2, L21)

来源:Toxin and Toxin Target Database (T3DB)