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THE EFFECTS OF ATRAZINE METABOLITES ON PUBERTY AND THYROID FUNCTION IN THE MALE WISTAR RAT
Citation:
Stoker, T E., D. L. Guidici, S C. Laws, AND R L. Cooper. THE EFFECTS OF ATRAZINE METABOLITES ON PUBERTY AND THYROID FUNCTION IN THE MALE WISTAR RAT. TOXICOLOGICAL SCIENCES 67(2):198-206, (2002).
Description:
The Effects of Atrazine Metabolites on Puberty and Thyroid Function in the Male Wistar Rat. Stoker, T.E1., Guidici, D.L.2, Laws, S.C.2 and Cooper, R.L.2 Gamete and Early Embryo Biology Branch and 2 Endocrinology Branch, Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory,
Office of Research and Development,U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina, 27711.
Recently we reported that atrazine (ATR), a chlorotriazine herbicide, alters the onset of puberty in male Wistar rats. In this study, we examined the same reproductive parameters in the developing male rat following a similar exposure to the primary, chlorinated metabolites of atrazine. Intact male Wistar rats were gavaged from postnatal day (PND) 23 through PND 53 and several reproductive endpoints were examined according to the pubertal protocol. The doses selected were the molar equivalents to atrazine in our previous work. Deethylatrazine (DEA), Deisopropyl-atrazine (DIA), and Diaminochlorotriazine (DACT) were administered by gavage at doses equivalent to the atrazine equimolar doses (AEDs) of 6.25,12.5, 25, 50, 100 or 200 mg/kg. Preputial separation (PPS) was significantly delayed by DEA at 25, 100 and 200 AED, by DIA at 25, 100 and 200 AED and by DACT at 12.5 through 200 AED. When the males were killed on PND 53, DEA (100 and 200 AED) and DIA (50 through 200 AED) and DACT (200 AED) treatments caused a significant reduction in ventral prostate weight, while only the highest doses of DIA and DEA resulted in a significant decrease in lateral prostate weight. Seminal vesicle weight was reduced by DEA (25, 100 and 200 AED); DIA (100 and 200 mg/kg/day); and 100 and 200 AED of DACT. Epididymal weights were reduced in the DEA (200 AED), DIA (200) and DACT (100 and 200 mg/kg/day) treatment groups. Serum testosterone was reduced only in the the males receiving the two highest doses of DIA. Serum estrone was increased in the two highest doses of the DACT group, while serum estradiol was not different in any group. No differences were observed in any of the thyroid measures. In summary, the metabolites of ATR delay puberty in a manner similar to that observed in the previous study testing atrazine. These data also suggest that the three chlorinated metabolites are similar to ATR, by affecting the CNS control of the secretion of steroids and subsequent development of the reproductive tract.