title: Effects of methotrexate on calcium flux in rat liver mitochondria, microsomes and plasma membrane vesicles.
abstract: The metabolic effects of methotrexate in perfused livers are similar to those exerted by hormones acting through Ca(2+)-dependent mechanisms. The aim of the present study was to determine whether the effects of methotrexate are mediated by a direct action on cellular Ca(2+) fluxes. Methotrexate did not affect the ATP-dependent (45)Ca(2+) uptake by mitochondria, microsomes and inside-out plasma membrane vesicles and Ca(2+) efflux from plasma membrane vesicles. However, methotrexate was able to stimulate (45)Ca(2+) release from preloaded microsomes. The amount of Ca(2+) released by methotrexate was similar to that induced by IP(3). Methotrexate could be acting through the capacitative calcium entry mechanism.
authors.affiliation: Laboratory of Biological Oxidations, Department of Biochemistry, University of Maringá, 87020900 Maringá, Brazil.
authors.forename: Clairce L S
authors.initials: CL
authors.lastname: Pagadigorria
authors.forename: Fernanda
authors.initials: F
authors.lastname: Marcon
authors.forename: Ana M
authors.initials: AM
authors.lastname: Kelmer-Bracht
authors.forename: Adelar
authors.initials: A
authors.lastname: Bracht
authors.forename: Emy L
authors.initials: EL
authors.lastname: Ishii-Iwamoto
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D008727:Methotrexate / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000187:drug effects* / Q000378:metabolism; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002118:Calcium; D008727:Methotrexate