Inhibitor action on placental calcium transport.
Calcif Tissue Int
; 48(1): 7-12, 1991 Jan.
Article
em En
| MEDLINE
| ID: mdl-1826093
ABSTRACT
Human term placental lobules were dually perfused with Krebs Ringer solution at 37 degrees C under open circuit conditions. Provided that perfusate Ca2+ concentrations were between 2.33 and 2.55 mM, there was a steady release of Ca2+ into the fetal circulation and uptake of Ca2+ from the maternal circulation. There was no significant calcium (Ca) protein binding in the perfusates. Addition of dinitrophenol altered the release of Ca2+ to an uptake on the fetal circuit and enhanced Ca2+ uptake on the maternal circuit. It also produced a release of potassium (K)+ and an uptake of Na+ on both sides of the placenta. Ouabain had no significant effect on Ca movements although it produced a marked release of K+ into the fetal perfusate. The effect of cooling on the fetal circuit was similar to that of dinitrophenol (DNP), although it did not produce significant changes in either Ca2+ or K+ movements on the maternal side of the lobule. Both DNP and cooling reduced the Ca concentration ratio between fetal and maternal outflows to unity. Replacement of Na+ by choline Ringer had only transient effect on the extraction of 45Ca from fetal perfusate. These observations indicate that a Ca2+/Na (sodium)+ exchanger does not make a major contribution to the transplacental movement of Ca2+ from mother to fetus and that this process is more probably associated with membrane-bound ATPases.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ouabaína
/
Placenta
/
Cálcio
/
Dinitrofenóis
Limite:
Female
/
Humans
/
Pregnancy
Idioma:
En
Revista:
Calcif Tissue Int
Ano de publicação:
1991
Tipo de documento:
Article
País de afiliação:
Reino Unido