Two-Generation Reproductive Toxicity Study of Resorcinol Administered Via Drinking Water to Crl:CD(SD) Rats

were assessed in a regulatory guideline compliant two-generation reproduction study in Crl:CD(SD) rats. Expanded end points of thyroid gland (TG) function were added because of clinical case reports indicating human TG toxicity. Average daily resorcinol in-take (mg/kg) at the 3000 mg/L concentration was 233 in F0 and F1 males, whereas in females it was 304 (premating/gestation) and 660 (lactation). No resorcinol ingestion-related clinical signs of toxicity were observed. Furthermore, neither gross morphologic anomalies nor effects on reproductive function or thyroid hormone levels were detectable. Body weight reductions occurred in 3000 mg/L F0 and F1 animals and were more pronounced in males. However, there was no evidence of either cumulative toxicity in the second generation or of enhanced sensitivity to resorcinol in pregnant/lactating females. Water intake was lower in 3000 mg/L rats of both generations and intermittently, to a lesser extent, a