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

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observed in the pair-fed group. Reduced ventral prostate and seminal vesicle weights (both organs
being androgen-dependent) paralleled the lower testosterone concentrations. Again, decreased ventral
prostate and seminal vesicle weights were noted in pair-fed rats. Additionally, lower LH concentrations
were observed in groups treated with atrazine at 100 mg/kg bw per day and greater, as well
as in pair-fed rats. A delay in preputial separation by about 3 and 4 days was observed at doses of 100
and 200 mg/kg bw per day, respectively (Trentacoste et al., 2001).
In a study on the effects of atrazine on pubertal development and thyroid function in male
rats, male Wistar rats were given atrazine (purity, 97.1%) at a dose of 0, 6.25 (preputial separation
study only) 12.5, 25, 50, 100, 150, or 200 mg/kg bw per day by gavage on postnatal days 23–53. An
additional control group was included that was pair-fed with the group at 200 mg/kg bw per day in
order to detect any effects caused by the reduced food consumption observed at this dose. Preputial
separation was monitored from postnatal day 33 onwards. The majority of the males were killed
on postnatal day 53. The pituitary, testes, ventral and lateral prostates, epididymides, and seminal
vesicles with coagulating gland were removed and weighed. Blood was analysed for TSH, T4, T3,
LH, prolactin, E2 and estrone. Additionally, concentrations of LH and prolactin were determined in
the anterior pituitaries. A subgroup of males in the control group and males at the highest dose was
killed on day 45 as described in the previous study for determination of LH receptors as well as serum
and intratesticular testosterone content. Finally, another subgroup of rats was killed on postnatal day
120 to examine the reversibility of the effects.
Body weights at 200 mg/kg bw per day were significantly decreased (−17% at postnatal day 53)
and returned to normal at postnatal day 120, while body weights of pair-fed rats were decreased to a
comparable extent (−14% at postnatal day 53). A dose-dependent decrease in ventral prostate weights
was observed with atrazine at doses of 50 mg/kg bw per day and greater and in the pair-fed group;
this effect was still seen at postnatal day 120 at 200 mg/kg bw per day. Seminal vesicle and epididymal
weights were decreased on postnatal day 53 at 200 mg/kg bw per day and in the pair-fed group.
The latter effects were no longer seen at postnatal day 120. There was no effect of treatment on testes
weight.
Preputial separation was significantly delayed at 12.5, 50, 100, 150, and 200 mg/kg bw per day
(by 2.3, 1.7, 1.7, 1.7, and 3 days, respectively), while there was no such effect in a separate group at a
dose of 6.25 mg/kg per day. Preputial separation was also delayed (by 2 days) in the pair-fed control
group, although significantly less than in the group at 200 mg/kg bw per day.
Serum testosterone concentrations were decreased at doses of 25 mg/kg bw per day and greater
at postnatal day 53 and at 200 mg/kg bw per day at postnatal day 45; however, the decreases were not
statistically significant. Intratesticular testosterone concentration was significantly lower at 200 mg/kg
bw per day on postnatal day 45, but not on postnatal day 53. Testosterone concentrations in the pairfed
rats were not significantly different to those in rats in the control group that had access to food ad
libitum. There was a dose-dependent increase in serum E2 and estrone concentrations on postnatal day
53; however, this increase was statistically significant only at 200 mg/kg bw per day, while concentrations
in the pair-fed group were comparable to those in the control group that had access to food ad
libitum.
There was a significant trend for a dose-dependent decrease in serum LH concentrations on
postnatal day 53; however, mean LH concentrations were not significantly different from those of the
controls. Prolactin was reduced at doses of 150 mg/kg bw per day and greater, but the differences
failed to reach statistical significance. The number of LH receptors in the testes was not altered by
treatment. Serum LH and prolactin concentrations were comparable in the pair-fed group and the
rats in the control group that had access to food ad libitum. Serum T3 concentration was significantly
increased at 200 mg/kg bw per day, while serum TSH and T4 concentrations were unaffected by treatment.
Serum TSH, T3, T4, LH and prolactin concentrations in the pair-fed group were comparable to
ATRAZINE 37–138 JMPR 2007