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. 1999 May 1;339(Pt 3):555–561.

Extracellular heavy-metal ions stimulate Ca2+ mobilization in hepatocytes.

T J McNulty 1, C W Taylor 1
PMCID: PMC1220190  PMID: 10215593

Abstract

Populations of hepatocytes in primary culture were loaded with fura 2 and the effects of extracellular heavy-metal ions were examined under conditions that allowed changes in fura 2 fluorescence (R340/360, the ratio of fluorescence recorded at 340 and 360 nm) to be directly attributed to changes in cytosolic free [Ca2+] ([Ca2+]i). In Ca2+-free media, Ni2+ [EC50 (concentration causing 50% stimulation) approximately 24+/-9 microM] caused reversible increases in [Ca2+]i that resulted from mobilization of the same intracellular Ca2+ stores as were released by [Arg8]vasopressin. The effects of Ni2+ were not mimicked by increasing the extracellular [Mg2+], by addition of MnCl2, CoCl2 or CdCl2 or by decreasing the extracellular pH from 7.3 to 6.0; nor were they observed in cultures of smooth muscle, endothelial cells or pituitary cells. CuCl2 (80 microM), ZnCl2 (80 microM) and LaCl3 (5 mM) mimicked the ability of Ni2+ to evoke Ca2+ mobilization. The response to La3+ was sustained even in the absence of extracellular Ca2+, probably because La3+ also inhibited Ca2+ extrusion. Although Ni2+ entered hepatocytes, from the extent to which it quenched fura 2 fluorescence the free cytosolic [Ni2+] ([Ni2+]i) was estimated to be <5 nM at the peak of the maximal Ni2+-evoked Ca2+ signals and there was no correlation between [Ni2+]i and the amplitude of the evoked increases in [Ca2+]i. We conclude that extracellular Ni2+, Zn2+, Cu2+ and La3+, but not all heavy-metal ions, evoke an increase in [Ca2+]i in hepatocytes by stimulating release of the hormone-sensitive intracellular Ca2+ stores and that they may do so by interacting with a specific cell-surface ion receptor. This putative ion receptor may be important in allowing hepatocytes to contribute to regulation of plasma heavy-metal ions and may mediate responses to Zn2+ released into the portal circulation with insulin.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Aida K., Koishi S., Tawata M., Onaya T. Molecular cloning of a putative Ca(2+)-sensing receptor cDNA from human kidney. Biochem Biophys Res Commun. 1995 Sep 14;214(2):524–529. doi: 10.1006/bbrc.1995.2318. [DOI] [PubMed] [Google Scholar]
  2. Arslan P., Di Virgilio F., Beltrame M., Tsien R. Y., Pozzan T. Cytosolic Ca2+ homeostasis in Ehrlich and Yoshida carcinomas. A new, membrane-permeant chelator of heavy metals reveals that these ascites tumor cell lines have normal cytosolic free Ca2+. J Biol Chem. 1985 Mar 10;260(5):2719–2727. [PubMed] [Google Scholar]
  3. Berridge M. J. Inositol trisphosphate and calcium signalling. Nature. 1993 Jan 28;361(6410):315–325. doi: 10.1038/361315a0. [DOI] [PubMed] [Google Scholar]
  4. Beuers U., Nathanson M. H., Isales C. M., Boyer J. L. Tauroursodeoxycholic acid stimulates hepatocellular exocytosis and mobilizes extracellular Ca++ mechanisms defective in cholestasis. J Clin Invest. 1993 Dec;92(6):2984–2993. doi: 10.1172/JCI116921. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Brand I. A., Kleineke J. Intracellular zinc movement and its effect on the carbohydrate metabolism of isolated rat hepatocytes. J Biol Chem. 1996 Jan 26;271(4):1941–1949. doi: 10.1074/jbc.271.4.1941. [DOI] [PubMed] [Google Scholar]
  6. Brown E. M., Gamba G., Riccardi D., Lombardi M., Butters R., Kifor O., Sun A., Hediger M. A., Lytton J., Hebert S. C. Cloning and characterization of an extracellular Ca(2+)-sensing receptor from bovine parathyroid. Nature. 1993 Dec 9;366(6455):575–580. doi: 10.1038/366575a0. [DOI] [PubMed] [Google Scholar]
  7. Brown E. M., Vassilev P. M., Hebert S. C. Calcium ions as extracellular messengers. Cell. 1995 Dec 1;83(5):679–682. doi: 10.1016/0092-8674(95)90180-9. [DOI] [PubMed] [Google Scholar]
  8. Byron K. L., Taylor C. W. Spontaneous Ca2+ spiking in a vascular smooth muscle cell line is independent of the release of intracellular Ca2+ stores. J Biol Chem. 1993 Apr 5;268(10):6945–6952. [PubMed] [Google Scholar]
  9. Conklin B. R., Bourne H. R. Homeostatic signals. Marriage of the flytrap and the serpent. Nature. 1994 Jan 6;367(6458):22–22. doi: 10.1038/367022a0. [DOI] [PubMed] [Google Scholar]
  10. Crofts J. N., Barritt G. J. The liver cell plasma membrane Ca2+ inflow systems exhibit a broad specificity for divalent metal ions. Biochem J. 1990 Aug 1;269(3):579–587. doi: 10.1042/bj2690579. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Duddy S. K., Kass G. E., Orrenius S. Ca2(+)-mobilizing hormones stimulate Ca2+ efflux from hepatocytes. J Biol Chem. 1989 Dec 15;264(35):20863–20866. [PubMed] [Google Scholar]
  12. Dwyer S. D., Zhuang Y., Smith J. B. Calcium mobilization by cadmium or decreasing extracellular Na+ or pH in coronary endothelial cells. Exp Cell Res. 1991 Jan;192(1):22–31. doi: 10.1016/0014-4827(91)90152-k. [DOI] [PubMed] [Google Scholar]
  13. Grynkiewicz G., Poenie M., Tsien R. Y. A new generation of Ca2+ indicators with greatly improved fluorescence properties. J Biol Chem. 1985 Mar 25;260(6):3440–3450. [PubMed] [Google Scholar]
  14. Hebert S. C., Brown E. M. The extracellular calcium receptor. Curr Opin Cell Biol. 1995 Aug;7(4):484–492. doi: 10.1016/0955-0674(95)80004-2. [DOI] [PubMed] [Google Scholar]
  15. Hughes B. P., Barritt G. J. Inhibition of the liver cell receptor-activated Ca2+ inflow system by metal ion inhibitors of voltage-operated Ca2+ channels but not by other inhibitors of Ca2+ inflow. Biochim Biophys Acta. 1989 Oct 9;1013(3):197–205. doi: 10.1016/0167-4889(89)90135-3. [DOI] [PubMed] [Google Scholar]
  16. Juhlin C., Lundgren S., Johansson H., Lorentzen J., Rask L., Larsson E., Rastad J., Akerström G., Klareskog L. 500-Kilodalton calcium sensor regulating cytoplasmic Ca2+ in cytotrophoblast cells of human placenta. J Biol Chem. 1990 May 15;265(14):8275–8279. [PubMed] [Google Scholar]
  17. Karjalainen A., Bygrave F. L. Nickel: an agent for investigating the relation between hormone-induced Ca2+ influx and bile flow in the perfused rat liver. Cell Calcium. 1995 Sep;18(3):214–222. doi: 10.1016/0143-4160(95)90066-7. [DOI] [PubMed] [Google Scholar]
  18. Kass G. E., Chow S. C., Gahm A., Webb D. L., Berggren P. O., Llopis J., Orrenius S. Two separate plasma membrane Ca2+ carriers participate in receptor-mediated Ca2+ influx in rat hepatocytes. Biochim Biophys Acta. 1994 Sep 8;1223(2):226–233. doi: 10.1016/0167-4889(94)90230-5. [DOI] [PubMed] [Google Scholar]
  19. Magneson G. R., Puvathingal J. M., Ray W. J., Jr The concentrations of free Mg2+ and free Zn2+ in equine blood plasma. J Biol Chem. 1987 Aug 15;262(23):11140–11148. [PubMed] [Google Scholar]
  20. Miledi R., Parker I., Woodward R. M. Membrane currents elicited by divalent cations in Xenopus oocytes. J Physiol. 1989 Oct;417:173–195. doi: 10.1113/jphysiol.1989.sp017796. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Nemeth E. F., Scarpa A. Rapid mobilization of cellular Ca2+ in bovine parathyroid cells evoked by extracellular divalent cations. Evidence for a cell surface calcium receptor. J Biol Chem. 1987 Apr 15;262(11):5188–5196. [PubMed] [Google Scholar]
  22. Palade P., Dettbarn C., Brunder D., Stein P., Hals G. Pharmacology of calcium release from sarcoplasmic reticulum. J Bioenerg Biomembr. 1989 Apr;21(2):295–320. doi: 10.1007/BF00812074. [DOI] [PubMed] [Google Scholar]
  23. Riccardi D., Park J., Lee W. S., Gamba G., Brown E. M., Hebert S. C. Cloning and functional expression of a rat kidney extracellular calcium/polyvalent cation-sensing receptor. Proc Natl Acad Sci U S A. 1995 Jan 3;92(1):131–135. doi: 10.1073/pnas.92.1.131. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Rooney T. A., Sass E. J., Thomas A. P. Characterization of cytosolic calcium oscillations induced by phenylephrine and vasopressin in single fura-2-loaded hepatocytes. J Biol Chem. 1989 Oct 15;264(29):17131–17141. [PubMed] [Google Scholar]
  25. Ruat M., Molliver M. E., Snowman A. M., Snyder S. H. Calcium sensing receptor: molecular cloning in rat and localization to nerve terminals. Proc Natl Acad Sci U S A. 1995 Apr 11;92(8):3161–3165. doi: 10.1073/pnas.92.8.3161. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Shankar V. S., Alam A. S., Bax C. M., Bax B. E., Pazianas M., Huang C. L., Zaidi M. Activation and inactivation of the osteoclast Ca2+ receptor by the trivalent cation, La3+. Biochem Biophys Res Commun. 1992 Sep 16;187(2):907–912. doi: 10.1016/0006-291x(92)91283-v. [DOI] [PubMed] [Google Scholar]
  27. Shankar V. S., Bax C. M., Alam A. S., Bax B. E., Huang C. L., Zaidi M. The osteoclast Ca2+ receptor is highly sensitive to activation by transition metal cations. Biochem Biophys Res Commun. 1992 Sep 16;187(2):913–918. doi: 10.1016/0006-291x(92)91284-w. [DOI] [PubMed] [Google Scholar]
  28. Shankar V. S., Bax C. M., Bax B. E., Alam A. S., Moonga B. S., Simon B., Pazianas M., Huang C. L., Zaidi M. Activation of the Ca2+ "receptor" on the osteoclast by Ni2+ elicits cytosolic Ca2+ signals: evidence for receptor activation and inactivation, intracellular Ca2+ redistribution, and divalent cation modulation. J Cell Physiol. 1993 Apr;155(1):120–129. doi: 10.1002/jcp.1041550116. [DOI] [PubMed] [Google Scholar]
  29. Slomianka L. Neurons of origin of zinc-containing pathways and the distribution of zinc-containing boutons in the hippocampal region of the rat. Neuroscience. 1992;48(2):325–352. doi: 10.1016/0306-4522(92)90494-m. [DOI] [PubMed] [Google Scholar]
  30. Smith J. B., Dwyer S. D., Smith L. Cadmium evokes inositol polyphosphate formation and calcium mobilization. Evidence for a cell surface receptor that cadmium stimulates and zinc antagonizes. J Biol Chem. 1989 May 5;264(13):7115–7118. [PubMed] [Google Scholar]
  31. Smith J. B., Dwyer S. D., Smith L. Lowering extracellular pH evokes inositol polyphosphate formation and calcium mobilization. J Biol Chem. 1989 May 25;264(15):8723–8728. [PubMed] [Google Scholar]
  32. Storey D. J., Shears S. B., Kirk C. J., Michell R. H. Stepwise enzymatic dephosphorylation of inositol 1,4,5-trisphosphate to inositol in liver. Nature. 1984 Nov 22;312(5992):374–376. doi: 10.1038/312374a0. [DOI] [PubMed] [Google Scholar]
  33. Taylor C. W., Berridge M. J., Cooke A. M., Potter B. V. Inositol 1,4,5-trisphosphorothioate, a stable analogue of inositol trisphosphate which mobilizes intracellular calcium. Biochem J. 1989 May 1;259(3):645–650. doi: 10.1042/bj2590645. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Yamaguchi M. Regulatory effects of zinc and copper on the calcium transport system in rat liver nuclei. Relation to SH groups in the releasing mechanism. Biochem Pharmacol. 1993 Feb 24;45(4):943–948. doi: 10.1016/0006-2952(93)90180-5. [DOI] [PubMed] [Google Scholar]
  35. Zhang G. H., Yamaguchi M., Kimura S., Higham S., Kraus-Friedmann N. Effects of heavy metal on rat liver microsomal Ca2(+)-ATPase and Ca2+ sequestering. Relation to SH groups. J Biol Chem. 1990 Feb 5;265(4):2184–2189. [PubMed] [Google Scholar]

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