title: Effect of hypoxia on the calcium and magnesium content, lipid peroxidation level, and Ca²⁺-ATPase activity of syncytiotrophoblast plasma membranes from placental explants.
abstract: In the current study the possible relationship between the Ca(2+)/Mg(2+) ratio of human syncytiotrophoblast plasma membranes and their lipid peroxidation and Ca(2+)-ATPase activity was determined. Syncytiotrophoblast plasma membranes of placental explants cultured under hypoxia increased their lipid peroxidation and Ca(2+) content, diminished their Ca(2+)-ATPase activity, and kept their Mg(2+) content unchanged. Membranes preincubated with different concentrations of Ca(2+) increased their Ca(2+) content without changes in their Mg(2+) content. There is a direct relationship between Ca(2+) content and lipid peroxidation of the membranes, as well as an inverse relationship between their Ca(2+) content and Ca(2+)-ATPase activity. On the contrary, preincubation of membranes with different concentrations of Mg(2+) showed a higher Mg(2+) content without changing their lipid peroxidation and Ca(2+)-ATPase activity. Explants cultured under hypoxia in the presence of 4 mM MgSO4 showed similar values of lipid peroxidation and Ca(2+)-ATPase activity of their membranes compared to those of explants cultured under normoxia. Increased Ca(2+) content of the membranes by interacting with negatively charged phospholipids could result in destabilizing effects of the membrane structure, exposing hydrocarbon chains of fatty acids to the action of free radicals. Mg(2+) might exert a stabilizing effect of the membranes, avoiding their exposure to free radicals.
authors.affiliation: Laboratorio de Bioenergética Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), IVIC-CBB, Apartado Postal 21827, Caracas 1020A, Venezuela.
authors.forename: Delia I
authors.initials: DI
authors.lastname: Chiarello
authors.affiliation: Laboratorio de Bioenergética Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), IVIC-CBB, Apartado Postal 21827, Caracas 1020A, Venezuela.
authors.forename: Reinaldo
authors.identifier: 0000-0002-6434-1221
authors.initials: R
authors.lastname: Marín
authors.affiliation: Laboratorio de Bioenergética Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), IVIC-CBB, Apartado Postal 21827, Caracas 1020A, Venezuela.
authors.forename: Fulgencio
authors.identifier: 0000-0003-4148-4630
authors.initials: F
authors.lastname: Proverbio
authors.affiliation: Laboratorio de Química Analítica, Centro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado Postal 21827, Caracas 1020A, Venezuela.
authors.forename: Zully
authors.initials: Z
authors.lastname: Benzo
authors.affiliation: Laboratorio de Bioenergética Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), IVIC-CBB, Apartado Postal 21827, Caracas 1020A, Venezuela.
authors.forename: Sandy
authors.initials: S
authors.lastname: Piñero
authors.affiliation: Laboratorio de Bioenergética Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), IVIC-CBB, Apartado Postal 21827, Caracas 1020A, Venezuela.
authors.forename: Desirée
authors.initials: D
authors.lastname: Botana
authors.affiliation: Laboratorio de Bioenergética Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), IVIC-CBB, Apartado Postal 21827, Caracas 1020A, Venezuela.
authors.forename: Cilia
authors.initials: C
authors.lastname: Abad
mesh_terms: D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D015687:Cell Hypoxia / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D015227:Lipid Peroxidation / Q000502:physiology*; D008274:Magnesium / Q000378:metabolism*; D010920:Placenta / Q000166:cytology / Q000378:metabolism*; D011225:Pre-Eclampsia / Q000378:metabolism / Q000473:pathology; D011247:Pregnancy; D014327:Trophoblasts / Q000378:metabolism*; D055815:Young Adult
chemical_list: D000252:Calcium-Transporting ATPases; D008274:Magnesium; D002118:Calcium