Whole Zebrafish Cytochrome P450 Assay for Assessing Drug Metabolism and Safety - Zebrafish: Methods for Assessing Drug Safety and Toxicity - page 109

9.4.4 Comparison of CYP3A4 Functional Activity
in Zebrafish and Mammals

To further validate use of the microplate-based whole zebrafish CYP3A4 func-
tional assay for assessing drug metabolism and safety, we compared results in
zebrafish with results in mammals. For all CYP inhibitors and inducers tested
in zebrafish, effects in mammalian models have been investigated or reported in
clinical trials. As shown in Table 9.3, results from our whole zebrafish microplate
CYP3A4 functional activity assay correlated well with results in mammals.
Overall prediction success rate for CYP3A4 inhibition and induction in zebrafish
was 86%: 100% for inhibition and 71% for induction. According to criteria for
assessing the predictive value of a new assay developed by the European Center for
the Validation of Alternative Methods (ECVAM) (Genschow et al., 2002), the
assaywas ranked “good” ( 85%)

for identifying inhibitors. These data suggest that zebrafish exhibit comparable
CYP drug profiles as mammals and that the whole zebrafish CYP microplate assay
represents a predictive, reproducible animal model for assessing drug metabolism
and safety.

75%) for identifying inducers and “excellent” (

> >

9.5 CONCLUSIONS

Since single zebrafish embryos and larvae can be maintained in fluid volumes as small
as 100 mL for the first week of development, physiologically intact animals can be
maintained in individual microtiter wells, an advantage that no other vertebrate model
provides. In addition to the microplate-based whole zebrafish CYP assay, we have
used similar principles to develop quantitative assays for angiogenesis, Src kinase,
TUNEL, caspase, ROS, and cancer cell xenotransplant. Accumulating data suggest
that in vivo zebrafish microplate assays are highly sensitive, reproducible, and
relatively high throughput.

ACKNOWLEDGMENT

This research was supported by a grant from the National Institutes of Health:
2R44GM083366.

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