Evaluation of dietary dose administration as an alternative to oral gavage in the rodent uterotrophic and Hershberger assays.

In this study, equivalent doses of positive control chemicals administered via dietary and gavage routes of administration were compared in the uterotrophic (17α-ethinyl estradiol) and Hershberger (flutamide, linuron, dichloro-2,2-bis(4-chlorophenyl) ethane; 4,4'-DDE) assays in ovariectomized and castrated rats, respectively. For all positive control chemicals tested, statistically significant changes in organ weights and decreases in food consumption were observed by both routes of test substance administration. Decreased body weight gain observed for dietary linuron and 4,4'-DDE indicates that the maximum tolerated dose was exceeded. Hershberger dietary administration resulted in a similar blood exposure (AUC24) for each positive control chemical when compared to gavage. Overall, the correlation in organ weight changes for both the uterotrophic and Hershberger assays suggest that dietary administration is an acceptable route of exposure with similar sensitivity to oral gavage dosing for evaluation of the endocrine potential of a test substance and represents a more appropriate route of test substance administration for most environmental exposure scenarios. PMID: 33181237 [PubMed - as supplied by publisher]
Source: Regulatory Toxicology and Pharmacology : RTP - Category: Toxicology Authors: Tags: Regul Toxicol Pharmacol Source Type: research