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

144
Benzazimide
(azinphos-methyl
metabolite in
rats)
Rat SD Males and
females
(4)
DMSO 98.1 412 (fasted
males)
269 (fasted
females)
CMC NS 576 (fasted
males)
368 (fasted
f emales) 576
(non-fasted
males)
487 (nonfasted
females)
DMSO NS 330 (fasted
males and
females)
Crawford &
Anderson
(1974); Annex 1,
r eference 64 a
Rat
Males and
females
(NS)
Lamb &
A nderson,
(1974); Annex 1,
reference 64 b
Methyl
b enzazimide
(azinphos-methyl
metabolite in
rats)
Rat SD Males and
females
(4)
Crawford &
Anderson
(1974); Annex 1,
r eference 64
Rat
Males and
females
(NS)
CMC NS 412 (fasted
males)
390 (fasted
f emales) 524
(non-fasted
males)
460 (nonfasted
females)
Lamb &
A nderson
(1974); A nnex 1,
r eference 64 b
CMC, carboxymethyl cellulose; DMSO, dimethyl sulfoxide; NS, not stated; NZW, New Zealand White; SD, Sprague-
Dawley.
a
Modified with reference to original data.
b
Original data not provided.
Groups of 10 male and 10 female CD rats were given azinphos-methyl (purity, 93%; in corn
oil) at a dose of 0, 0.22, 0.86, 3.44 mg/kg bw per day by gavage for 13 weeks. All rats were examined
at least three times per day for mortality and clinical signs. Food consumption and body weights were
recorded weekly, and water consumption was recorded daily. Food conversion ratios were calculated
as the amount of food consumed per unit body weight gained. Ophthalmoscopic examinations were
performed on all rats before the commencement of treatment and on rats in the control and the highest
dose groups after 12 weeks of treatment. Haematology and clinical chemistry parameters (including
cholinesterase activity) were determined at termination, after which all animals were given a
macroscopic examination, and selected organs were removed and weighed. Histopathological examination
was performed on selected tissues harvested from rats in the control group and in the group at
the highest dose, while kidneys, liver and lungs were examined in all rats.
There were no treatment-related deaths. Salivation was observed in males at and above
0.86 mg/kg bw per day from approximately week 3, with the majority of rats being affected from
week 8 at 0.86 (up to 8 out of 10) and 3.44 mg/kg bw per day (up to 10 out of 10). Salivation was
observed shortly after dosing in the majority of males, but occasionally it was seen before dosing or
up to an hour after dosing in some animals. Salivation was observed infrequently in females with the
exception of 2 out of 20 rats at the intermediate dose only during week 7, and 4 out of 10 rats at the
highest dose only during week 9. There were no treatment-related effects on ophthalmoscopy, bodyweight
gain, or food and water consumption. However, there was a clear treatment-related effect on
the inhibition of plasma butyryl, plasma acetyl, erythrocyte and brain cholinesterase activities in
males and females (Table 3).
AZINPHOS-METHYL 139–172 JMPR 2007