Intra-
and Interlaboratory Reliability of a Cryopreserved
Trout Hepatocyte Assay for the Prediction of Chemical Bioaccumulation
Potential
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Abstract
Measured
rates of intrinsic clearance determined using cryopreserved
trout hepatocytes can be extrapolated to the whole animal as a means
of improving modeled bioaccumulation predictions for fish. To date,
however, the intra- and interlaboratory reliability of this procedure
has not been determined. In the present study, three laboratories
determined in vitro intrinsic clearance of six reference compounds
(benzo[<i>a</i>]pyrene, 4-nonylphenol, di-<i>tert</i>-butyl phenol, fenthion, methoxychlor and <i>o</i>-terphenyl)
by conducting substrate depletion experiments with cryopreserved trout
hepatocytes from a single source. <i>O</i>-terphenyl was
excluded from the final analysis due to nonfirst-order depletion kinetics
and significant loss from denatured controls. For the other five compounds,
intralaboratory variability (% CV) in measured in vitro intrinsic
clearance values ranged from 4.1 to 30%, while interlaboratory variability
ranged from 27 to 61%. Predicted bioconcentration factors based on
in vitro clearance values exhibited a reduced level of interlaboratory
variability (5.3–38% CV). The results of this study demonstrate
that cryopreserved trout hepatocytes can be used to reliably obtain
in vitro intrinsic clearance of xenobiotics, which provides support
for the application of this in vitro method in a weight-of-evidence
approach to chemical bioaccumulation assessment