Linked Life Data

1550216

Source:http://linkedlifedata.com/resource/pubmed/id/1550216

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3 Pt 1
pubmed:dateCreated
1992-4-23
pubmed:abstractText
Calcium entry across the microvillous membrane of the human placental syncytiotrophoblast is the first step in the transfer of this important nutrient to the fetus. Calcium uptake by isolated microvillous membranes was time dependent. Equilibrium uptake was very much greater than could be explained by equilibration of the vesicle space with medium, indicating that calcium is bound to internal sites. Addition of the ionophore A23187 greatly increased the rates of influx and efflux, indicating that transport across the plasma membrane is rate limiting in entry. Concentration dependence data for calcium transport at 4 s fit well to a Michaelis-Menten equation having two saturable sites and diffusion. Calcium entry by both transporters was unaffected by calcium channel blockers but was strongly inhibited by the group II metals. The distinct inhibition constant values for strontium inhibition provided additional evidence for two transporters. Calcium binding fit well to a single-site model saturable in the micromolar range. In vivo, the saturable transport processes may mediate calcium entry into the syncytiotrophoblast and binding may regulate concentration within the placental microvilli.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
262
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
C789-94
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Transport and binding in calcium uptake by microvillous membrane of human placenta.
pubmed:affiliation
Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, Children's Hospital, St. Louis, Missouri 63110.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S.