Assessment of 3-Nitro-1,2,4-triazol-5-one as a Potential Endocrine Disrupting Chemical in Rats Using the Hershberger and Uterotrophic Bioassays

This study assessed endocrine disruption as a potential mechanism for these reproductive effects via the Hershberger and uterotrophic bioassays. These assays are 2 of the US Environmental Protection Agency’s tier 1 in vivo screens for the Endocrine Disruptor Screening Program that measure differences in androgen- and estrogen-sensitive tissue weights in castrated and ovariectomized rats. The gonadectomized rats were orally exposed to NTO in a corn oil vehicle at doses of 250, 500, or 1000 mg/kg body weight (bw)/d for 10 and 3 days for the Hershberger and uterotrophic assays, respectively, according to standard protocols. Male rats also received testosterone (0.2 mg/kg/d, subcutaneous) and antiandrogenic flutamide (3mg/kg/d, oral) as negative and positive controls, and females received 17 α-ethynyl estradiol (0.3 µg/d, subcutaneous) as positive controls. 3-Nitro-1,2,4-triazol-5-one caused neither a decrease in androgen-sensitive male reproductive selected tissue (seminal vesicles with fluid/without fluid, glans penis, Cowper gland, ventral prostrate, and levator ani–bulbocavernosus) weights nor a change in uterine weights. The results of this study provide no evidence to suggest that NTO acts like an estrogenic or antiandrogenic endocrine disruptor in rats at these doses.
Source: International Journal of Toxicology - Category: Toxicology Authors: Tags: Original Articles Source Type: research