Lundholm C E, Mathson K
Acta Pharmacol Toxicol (Copenh). 1986 Nov;59(5):410-5. doi: 10.1111/j.1600-0773.1986.tb00192.x.
Some metal ions, e.g. Hg2+, Cd2+ and Al3+, can have the effects as ecotoxicological agents, of causing eggshell thinning and breakage in birds. In a homogenate of the Ca2+-secreting part of the eggshell gland mucosa, a study was made of the influence of Hg2+, Cd2+, Cu2+, Pb2+, methyl-Hg+, Zn2+, V3+, Al3+ and Ni2+ in different concentrations on the rate of ATP-dependent 10(-4) M Ca2+ binding. All compounds had an inhibitory action. The most potent metal (Hg2+) produced 50% inhibition (IC50) at 1.1 X 10(-6) M, whereas this value for the least potent compound (Ni2+) was 9 X 10(-4) M. The specific Ca2+-Mg2+-ATPase activity was also inhibited by the tested metal ions. In all cases except methyl-Hg+ the IC50 for this activity was lower than that for Ca2+ binding. The most potent ion in this respect was Cd2+, with an IC50 of 8 X 10(-8) M, and the least potent was methyl-Hg+, with an IC50 of 1.4 X 10(-3) M. Pb2+ and Cd2+ in a concentration range of 10(-5)-10(-4) stimulated the Mg2+-ATPase activity, however, to almost the same extent as 10(-4) M Ca2+. A possible explanation for this effect is that these ions may have an affinity for sites of Ca2+ binding of the polypeptide calmodulin and thereby influence the Ca2+ metabolism of the shell gland mucosa.
一些金属离子，例如汞离子（Hg2+）、镉离子（Cd2+）和铝离子（Al3+），可作为生态毒理学因子，导致鸟类蛋壳变薄和破裂。在蛋壳腺黏膜分泌钙离子的匀浆中，研究了不同浓度的汞离子（Hg2+）、镉离子（Cd2+）、铜离子（Cu2+）、铅离子（Pb2+）、甲基汞离子（methyl-Hg+）、锌离子（Zn2+）、钒离子（V3+）、铝离子（Al3+）和镍离子（Ni2+）对依赖ATP的10(-4) M钙离子结合速率的影响。所有化合物均有抑制作用。最有效的金属（汞离子（Hg2+））在1.1×10(-6) M时产生50%的抑制（IC50），而最无效的化合物（镍离子（Ni2+））的该值为9×10(-4) M。受试金属离子也抑制了特定的钙离子-镁离子-ATP酶活性。除甲基汞离子（methyl-Hg+）外，在所有情况下该活性的IC50均低于钙离子结合的IC50。在这方面最有效的离子是镉离子（Cd2+），IC50为8×10(-8) M，最无效的是甲基汞离子（methyl-Hg+），IC50为1.4×10(-3) M。然而，浓度范围为10(-5)-10(-4) 的铅离子（Pb2+）和镉离子（Cd2+）刺激镁离子-ATP酶活性的程度几乎与10(-4) M钙离子相同。对此效应的一种可能解释是，这些离子可能对多肽钙调蛋白的钙离子结合位点具有亲和力，从而影响壳腺黏膜的钙离子代谢。
