Linked Life Data

9772200

Source:http://linkedlifedata.com/resource/pubmed/id/9772200

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1998-11-20
pubmed:abstractText
Previous studies have shown that, in general, young, postnatal animals are more sensitive than adults to the toxic effects of anticholinesterase (antiChE) pesticides. Paradoxically, often fetal brain cholinesterase (ChE) is less inhibited than maternal brain after gestational exposure to an antiChE, presumably due to placental and fetal detoxification of the antiChE. The present investigation was designed to study selected toxicokinetic and toxicodynamic factors surrounding the toxicity of chlorpyrifos (CPF; [O,O'-diethyl O-3,5,6-trichloro-2-pyridyl] phosphorothionate) in pregnant rats dosed repeatedly or singly during late gestation. Dams were dosed daily (po) with CPF in corn oil (0 or 7 mg/kg) on gestational days (GD) 14 to 18. Animals were euthanized at 2 to 120 h after the last dose and tissues were collected for enzyme analysis. Using this dosing regimen, we found that (1) the time of maximal ChE inhibition was the same (i.e., 5-10 h after dosing) for both maternal and fetal brain, (2) the degree of fetal brain ChE inhibition was 4.7 times less than maternal brain inhibition, and (3) the detoxification potential (i.e., carboxylesterase and chlorpyrifos-oxonase) of the fetal tissues was very low compared to the maternal tissues. A separate group of experiments showed that if pregnant dams received only one oral dose of 7 or 10 mg/kg CPF on GD18, the degree of ChE inhibition in the fetal brain was comparable to the maternal brain ChE inhibition. Taking into consideration the net increase (more than fourfold) in fetal brain ChE activity from GD14 to 18 in control animals, and the fact that maternal brain ChE was inhibited more than fetal brain ChE only in a repeated-dosing regimen, we conclude that the fetus is not genuinely protected from the toxic effects of a given dose of CPF. We propose that fetal brain ChE is simply able to recover more fully between each dose as compared to maternal brain ChE, giving the illusion that the fetal compartment is less affected than the maternal compartment.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0041-008X
pubmed:author
pubmed:issnType
Print
pubmed:volume
152
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
56-65
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:9772200-Animals, pubmed-meshheading:9772200-Brain, pubmed-meshheading:9772200-Brain Diseases, pubmed-meshheading:9772200-Carboxylesterase, pubmed-meshheading:9772200-Carboxylic Ester Hydrolases, pubmed-meshheading:9772200-Chlorpyrifos, pubmed-meshheading:9772200-Cholinesterase Inhibitors, pubmed-meshheading:9772200-Cholinesterases, pubmed-meshheading:9772200-Embryonic and Fetal Development, pubmed-meshheading:9772200-Esterases, pubmed-meshheading:9772200-Female, pubmed-meshheading:9772200-Fetus, pubmed-meshheading:9772200-Gestational Age, pubmed-meshheading:9772200-Liver, pubmed-meshheading:9772200-Metabolic Detoxication, Drug, pubmed-meshheading:9772200-Pregnancy, pubmed-meshheading:9772200-Prenatal Exposure Delayed Effects, pubmed-meshheading:9772200-Rats, pubmed-meshheading:9772200-Rats, Long-Evans
pubmed:year
1998
pubmed:articleTitle
Gestational exposure to chlorpyrifos: apparent protection of the fetus?
pubmed:affiliation
Curriculum in Toxicology, University of North Carolina, Chapel Hill, North Carolina, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.