4-Nonylphenol (NP) is a surfactant that is a well-known and widespread estrogenic endocrine disrupting chemical (EDC). Although it has been known that the affinity of NP to ERs is low, it has been suggested that low-dose NP has toxicity. In the present study, the endocrine disrupting effects on reproduction, and the weight of gonads, epididymis, and uterus were evaluated with the chronic lower-dose NP exposing. This study was designed by following the OECD test guideline 443 and subjected to a complete necropsy. In male, NP had an effect on the weight of the testis and epididymis in both F₀ and F₁. In females, NP decreased the weight of ovary and uterus in F₀ but not in pre-pubertal F₁ pubs. Fertility of male and female in F₀ or F₁ was no related with NP administration. The number of caudal-epididymal sperm by body weight (BW) was not different between groups in both F₀ and F₁. Besides, the difference of the sperm number between generations was not detected. The number of ovulated oocytes was similar between groups in F₀, but significantly decreased in NP 50 group of F₁. The litter size and sex ratios of offspring in F₁ and F₂ were not different. The accumulated mating rate and gestation period were not affected by the NP administration. Those results shows that chronic lower-dose NP administration has an effect of endocrine disruptor on the weight of gonads and epididymis of F₀ and F₁ but not in reproduction. Based on the results, it is suggested that chronic lower-dose NP exposing causes endocrine disruption in the weight of gonad and epididymis but not in the reproductive ability of next generations.

Jeong Won Baek

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