钙对大鼠铅吸收的影响。
The effect of calcium on lead absorption in rats.
作者信息
Meredith P A, Moore M R, Goldberg A
出版信息
Biochem J. 1977 Sep 15;166(3):531-7. doi: 10.1042/bj1660531.
The effects of Ca2+ on lead absorption as PbCl2 and 203PbCl2 were studied in rats. 1. Doubling of dietary calcium with Ca3(PO4)2 significantly decreased lead absorption as assessed by 203Pb retention, tissue lead concentration, urinary excretion of delta-aminolaevulinate and increased activities of delta-aminolaevulinate dehydratase and ferrochelatase. 2. Similar effects on lead absorption were shown by the Ca2+ salts, Cl-, CO32-, PO43-, SO42-, gluconate and glycerophosphate. 3. CaCl2 and calcium glycerophosphate were found to be most effective in decreasing lead absorption when administered immediately before lead dosage. 4. A negative exponential relationship was found between CaCl2 concentration and 203Pb absorption at 120h. The result suggest that, above 4 mmol of administered calcium, residual lead absorption is unaffected by increasing gastrointestinal calcium concentrations. 5. Increased systemic calcium had no effect on lead retention. 6. Calcium in the concentrations found in domestic hard-water supplies significantly decreased absorption of a solution of 203Pb dissolved in it compared with absorption of 203Pb dissolved in soft or distilled water. 7. Milk and skimmed milk were found to have no effect on 203Pb absorption in rats.
在大鼠中研究了钙离子对氯化铅（PbCl₂）和²⁰³PbCl₂形式铅吸收的影响。1. 用磷酸钙（Ca₃(PO₄)₂）使日粮钙含量加倍，通过²⁰³Pb潴留、组织铅浓度、δ-氨基乙酰丙酸的尿排泄量评估，显著降低了铅吸收，并提高了δ-氨基乙酰丙酸脱水酶和亚铁螯合酶的活性。2. 氯离子（Cl⁻）、碳酸根离子（CO₃²⁻）、磷酸根离子（PO₄³⁻）、硫酸根离子（SO₄²⁻）、葡萄糖酸根和甘油磷酸根等钙离子盐对铅吸收有类似影响。3. 发现氯化钙（CaCl₂）和甘油磷酸钙在铅给药前立即给药时，对降低铅吸收最有效。4. 在120小时时，发现氯化钙浓度与²⁰³Pb吸收之间呈负指数关系。结果表明，给予钙超过4 mmol时，胃肠道钙浓度增加对残留铅吸收无影响。5. 全身钙增加对铅潴留无影响。6. 与溶解在软水或蒸馏水中的²⁰³Pb相比，家庭硬水供应中发现的浓度的钙显著降低了溶解在其中的²⁰³Pb溶液的吸收。7. 发现牛奶和脱脂牛奶对大鼠²⁰³Pb吸收无影响。
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