Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1987-8-19
pubmed:abstractText
Gas uptake simulation methods were used to determine kinetic constants for trichloroethylene (TCE) and 1,1-dichloroethylene (1,1-DCE) metabolism in vivo in male Fischer 344 rats. Both are metabolized by single, saturable, oxidative pathways with high-affinity substrate binding. The allometrically scaled maximum velocities (Vmaxc) for TCE and 1,1-DCE were, respectively, 11 and 7.5 mg/hr (i.e., 84 and 77 mumol/hr). Gas uptake studies were also conducted with three mixed atmosphere exposures with the following initial concentrations in parts per million: 500 (1,1-DCE):2000 (TCE); 500 (1,1-DCE):500 (TCE); and 2000 (1,1-DCE):500 (TCE). Mixture uptake curves were described by a system of equations in which a full physiologically based pharmacokinetic (PB-PK) model was provided for each chemical and each was regarded as an inhibitor of the other's metabolism. A generic model was developed to accommodate multiple mechanisms of inhibitory interactions, i.e., competitive, noncompetitive, or uncompetitive. An excellent correspondence was obtained between predicted and observed behavior when the inhibition was assumed to be purely competitive with binding constants for TCE and 1,1-DCE set to 0.25 and 0.10 mg/liter, respectively; i.e., in vivo 1,1-DCE is a slightly better substrate for microsomal oxidation than is TCE. The PB-PK model which was successful in describing the mixture data was used to predict conditions under which 1,1-DCE hepatotoxicity would be expected in coexposure to constant concentration atmospheres of these two chloroethylenes. These predictions were compared with data on the increases in plasma liver enzymes resulting from exposures to either 1,1-DCE alone or to 1,1-DCE in combination with TCE.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0041-008X
pubmed:author
pubmed:issnType
Print
pubmed:day
30
pubmed:volume
89
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
149-57
pubmed:dateRevised
2005-6-9
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Quantitative evaluation of the metabolic interactions between trichloroethylene and 1,1-dichloroethylene in vivo using gas uptake methods.
pubmed:publicationType
Journal Article