Pesticide residues in food — 2007: Toxicological ... - ipcs inchem

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Table 12. Inhibition of plasma, erythrocyte and brain cholinesterase activity in F 0
and in F 1
pups
of rats fed diets containing azinphos-methyl
Dietary
concentration
(ppm)
Cholinesterase activity (% of values for controls)
F 0
males F 0
females F 1
pups
End of
m ating
End of pretreatment
Post-coital
day 11
Postnatal
day 5
Postnatal
day 28
Postnatal
day 5
Postnatal
day 28
Plasma
5
15
2.3
14***
ND
25*
ND
18
26*
46***
5
39**
ND
45 43*** 62*** 60*** 66*** 63***
Erythrocytes
5 19** ND ND 25** 47***
15 69*** 46*** 52*** 75*** 84***
ND
45 94*** 71*** 81*** 91*** 89***
Brain
5 1 10* ND ND 12 ND ND
15 ND 4 21** 38** 48*** 1 14
45 19** 55*** 69*** 66*** 68*** 17* 46***
From Holzum (1990); Annex 1, reference 64, modified by reference to original data.
* p < 0.05 ; ** p < 0.01 ; *** p < 0.001.
ND, not determined.
ND
ND
Table 13. Cholinesterase activity in dams (and their fetuses) given azinphos-methyl by gavage on
days 6–15 of gestation
Tissue
Cholinesterase activity
Dose (mg/kg bw per day)
0 0.5 1.0 2.0
Day 16
Plasma, kU/l (% of control) 1.73 (100%) 1.56 (90%) 1.64 (95%) 1.08 (63%)
Erythrocytes, kU/l (% of control) 0.38 (100%) 0.34 (90%) 0.34 (90%) 0.08* (21%)
Brain, U/g (% of control) 2.53 (100%) 2.70 (107%) 2.55 (101%) 1.55* (61%)
Day 20
Plasma, kU/l (% of control) 1.44 (100%) 1.47 (102%) 1.40 (97%) 1.32 (92%)
Erythrocytes, kU/l (% of control) 0.58 (100%) 0.59 (103%) 0.61 (106%) 0.44 (77%)
Brain, U/g (% of control) 2.67 (100%) 2.72 (102%) 2.46 (92%) 1.91* (72%)
Fetal brain, U/g (% of control) 1.04 (100%) 0.96 (91%) 1.04 (100%) 1.00 (96%)
From Kowalski et al. (1987a; 1987b); Annex 1, reference 64, modified by reference to original data; Astroff & Young
(1998).
* p < 0.05.
developmental toxicity was 2.0 mg/kg bw per day, on the basis of the absence of any effects at the
highest tested dose. The NOAEL for maternal toxicity was 1.0 mg/kg bw per day, on the basis of
the inhibition of brain cholinesterase activity seen on day 16 of gestation at 2.0 mg/kg bw per day
(Kowalski et al., 1987a, 1987b; Annex 1, reference 64, modified by reference to original data; Astroff
& Young, 1998).
AZINPHOS-METHYL 139–172 JMPR 2007