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ATRAZINE-INDUCED REPRODUCTIVE TRACT ALTERATIONS AFTER TRANSPLACENTAL AND LACTATIONAL EXPOSURE IN LONG-EVANS RAT PUPS
Citation:
RAYNER, J., R. R. ENOCH, DOUG C. WOLF, AND S. E. FENTON. ATRAZINE-INDUCED REPRODUCTIVE TRACT ALTERATIONS AFTER TRANSPLACENTAL AND LACTATIONAL EXPOSURE IN LONG-EVANS RAT PUPS. Presented at Endocrine Meeting, Boston, MA, June 23 - 26, 2006.
Description:
Studies have shown that early postnatal exposure to the common herbicide atrazine (ATR) will delay preputial separation (PPS) in Wistar rats and increase incidence of prostate inflammation in adults. To evaluate ATR exposure parameters required for pubertal delays (PPS), we used cross-fostering to determine if effects in pups developed from transplacental or lactational exposure. Timed-pregnant Long-Evans rats (N=20/group) were dosed by gavage on gestational days (GD) 15-19 with 100 mg ATR/kg body weight (BW) or 1% methylcellulose (controls, C). On PND1, half litters were cross-fostered, creating 4 treatment groups; C-C, ATR-C, C-ATR, and ATR-ATR (transplacental-milk as source, respectively). Body weight was recorded on PND4, PND22, onset of puberty, PND120, and PND220. At PND4 male offspring in the ATR-ATR groups weighed significantly less than C-C males, p<0.01. At PND22, weaning, there were no differences found in weight among the offspring. ATR-ATR male pups had significantly delayed PPS (2.6 d delay), but PPS was similar between offspring of the other groups (PPS at PND 41). BWs at PPS for C-ATR and ATR-ATR males were reduced by 6% and 9%, respectively, from that of C-C. On PND120, lateral prostate weights of males in the ATR-ATR group were significantly increased over C-C. Histological examination of the ventral and lateral prostates identified a statistically different distribution and severity of inflammation in ATR-C and C-ATR groups. By PND220, lateral prostate weights were significantly increased for ATR-C and ATR-ATR (p<0.02), but there were no differences in inflammation in either the lateral or ventral prostate. The distribution and severity of inflammation were not increased from those at PND120. These results suggest that in Long Evans rats, gestational ATR exposure delays PPS only when male offspring suckle an ATR dam, but leads to increased lateral prostate weight via transplacental exposure alone. This weight increase was not found to be associated with increased inflammation in the adult rat. (This is an abstract of a proposed presentation and does not necessarily reflect EPA policy)
Supported by NHEERL-DESE Cooperative Training in Environmental Sciences Research, EPA CT826513, and National Science Foundation Cooperative Agreement No. HRD-9978874.