Abstract
Inhibitors of SO4(2-) entry into and efflux from vesicles prepared from the brush border membrane of term human placenta have been studied, using 35SO4(2-) and an anion-exchange column assay. Divalent anions were found to be either potent or relatively feeble inhibitors of SO4(2-) uptake. Those which, like SO4(2-) itself, have a tetrahedral configuration, were strongly inhibitory and all of these anions were the metal oxides of elements of group VI (A and B) of the Periodic Table (chromate, molybdate, tungstate, selenate and thiosulphate). Divalent anions which were only weak inhibitors of SO4(2-) uptake were arsenate, phosphate and tetraborate. Chromate and to a lesser extent molybdate were effective inhibitors of SO4(2-) efflux from vesicles pre-loaded with SO4(2-). SO4(2-) efflux was insensitive to the electrical potential across the vesicle membrane. These results are discussed with respect to the mechanism for SO4(2-) transport across this membrane from mother to fetus and in the context of the transport to the feto-placental unit of the essential trace elements, selenium, chromium and molybdenum.
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Selected References
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- Ardüser F., Wolffram S., Scharrer E. Active absorption of selenate by rat ileum. J Nutr. 1985 Sep;115(9):1203–1208. doi: 10.1093/jn/115.9.1203. [DOI] [PubMed] [Google Scholar]
- Berner W., Kinne R., Murer H. Phosphate transport into brush-border membrane vesicles isolated from rat small intestine. Biochem J. 1976 Dec 15;160(3):467–474. doi: 10.1042/bj1600467. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Boyd C. A., Lund E. K. L-proline transport by brush border membrane vesicles prepared from human placenta. J Physiol. 1981 Jun;315:9–19. doi: 10.1113/jphysiol.1981.sp013728. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Boyd C. A., Shennan D. B. Human placental sulphate transport: studies on chorionic trophoblast brush border membrane vesicles. J Physiol. 1986 Aug;377:15–24. doi: 10.1113/jphysiol.1986.sp016173. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cardin C. J., Mason J. Molybdate and tungstate transfer by rat ileum. Competitive inhibition by sulphate. Biochim Biophys Acta. 1976 Dec 14;455(3):937–946. doi: 10.1016/0005-2736(76)90062-6. [DOI] [PubMed] [Google Scholar]
- Cardin C. J., Mason J. Sulphate transport by rat ileum. Effect of molybdate and other anions. Biochim Biophys Acta. 1975 Jun 11;394(1):46–54. doi: 10.1016/0005-2736(75)90203-5. [DOI] [PubMed] [Google Scholar]
- Cole D. E., Baldwin L. S., Stirk L. J. Increased inorganic sulfate in mother and fetus at parturition: evidence for a fetal-to-maternal gradient. Am J Obstet Gynecol. 1984 Mar 1;148(5):596–599. doi: 10.1016/0002-9378(84)90755-5. [DOI] [PubMed] [Google Scholar]
- Cole D. E. Sulfate transport in brush border membrane vesicles prepared from human placental syncytiotrophoblast. Biochem Biophys Res Commun. 1984 Aug 30;123(1):223–229. doi: 10.1016/0006-291x(84)90402-9. [DOI] [PubMed] [Google Scholar]
- Elgavish A., Smith J. B., Pillion D. J., Meezan E. Sulfate transport in human lung fibroblasts (IMR-90). J Cell Physiol. 1985 Nov;125(2):243–250. doi: 10.1002/jcp.1041250211. [DOI] [PubMed] [Google Scholar]
- Johnson L. W., Smith C. H. Glucose transport across the basal plasma membrane of human placental syncytiotrophoblast. Biochim Biophys Acta. 1985 Apr 26;815(1):44–50. doi: 10.1016/0005-2736(85)90472-9. [DOI] [PubMed] [Google Scholar]
- Knickelbein R. G., Aronson P. S., Dobbins J. W. Substrate and inhibitor specificity of anion exchangers on the brush border membrane of rabbit ileum. J Membr Biol. 1985;88(2):199–204. doi: 10.1007/BF01868433. [DOI] [PubMed] [Google Scholar]
- Liedtke C. M., Hopfer U. Mechanism of Cl- translocation across small intestinal brush-border membrane. II. Demonstration of Cl--OH- exchange and Cl- conductance. Am J Physiol. 1982 Mar;242(3):G272–G280. doi: 10.1152/ajpgi.1982.242.3.G272. [DOI] [PubMed] [Google Scholar]
- Löw I., Friedrich T., Burckhardt G. Properties of an anion exchanger in rat renal basolateral membrane vesicles. Am J Physiol. 1984 Mar;246(3 Pt 2):F334–F342. doi: 10.1152/ajprenal.1984.246.3.F334. [DOI] [PubMed] [Google Scholar]
- Lücke H., Stange G., Murer H. Sulphate-ion/sodium-ion co-transport by brush-border membrane vesicles isolated from rat kidney cortex. Biochem J. 1979 Jul 15;182(1):223–229. doi: 10.1042/bj1820223. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith N. C., Brush M. G., Luckett S. Preparation of human placental villous surface membrane. Nature. 1974 Nov 22;252(5481):302–303. doi: 10.1038/252302b0. [DOI] [PubMed] [Google Scholar]
- Wolffram S., Ardüser F., Scharrer E. In vivo intestinal absorption of selenate and selenite by rats. J Nutr. 1985 Apr;115(4):454–459. doi: 10.1093/jn/115.4.454. [DOI] [PubMed] [Google Scholar]
