Toxicological Sciences, Vol 52, 258-268, Copyright © 1999 by Society of Toxicology
RW Tyl, TL Neeper-Bradley, LC Fisher, DE Dodd, IM Pritts, PE Losco, JP Lyon and TD Landry
Twenty-eight 42-day-old pups/sex/group (F0) were exposed to toluene
diisocyanate vapor (TDI; 80% 2,4-TDI, 20% 2,6-TDI) by inhalation at 0.0,
0.02, 0.08, or 0.3 ppm, 6 h/day, 5 days/week, for 10 weeks, then mated
within groups for 3 weeks, with exposure 7 days/week during mating,
gestation, and lactation. F0 maternal animals were not exposed from
gestational day (gd) 20 through postnatal day (pnd) 4; maternal exposures
resumed on pnd 5. Twenty-eight weanlings/sex/group continued exposure for
12 weeks (starting on pnd 28) and were bred as described above. F0 and F1
parents and ten F1 and F2 weanlings/sex/group were necropsied, and adult
reproductive organs, pituitary, liver, kidneys, and upper respiratory tract
(target organs) were evaluated histologically in ten/sex/group. Adult
toxicity was observed in both sexes and generations at 0.08 and 0.3 ppm,
including occasional reductions in body weights and weight gain, clinical
signs of toxicity at 0.08 and 0.3 ppm, and histologic changes in the nasal
cavities at 0.02, 0.08, and 0.3 ppm (including rhinitis, a nonspecific
response to an irritating vapor, at all concentrations). There was no
reproductive toxicity, reproductive organ pathology, or effect on gestation
or lactation at any exposure concentration. Postnatal toxicity and reduced
body weights and weight gains during lactation occurred only in F2 litters
at 0.08 and 0.3 ppm. Therefore, under the conditions of this study, a no
observed adverse effect level (NOAEL) was not determined for adult
toxicity; the NOAEL for reproductive toxicity was at least 0.3 ppm, and the
NOAEL for postnatal toxicity was 0.02 ppm.
ARTICLES
Two-generation reproductive toxicity study of inhaled toluene diisocyanate vapor in CD rats
Bushy Run Research Center, Export, Pennsylvania, USA. rwt@rti.org
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