Background & Objectives: Methoxychlor(MET), an organochlorine insecticide, has been thought a potent endocrine disrupting chemical. The present study was undertaken to examine whether short-term exposure to MET can alter the onset of puberty and the associated reproductive parameters such as hormone receptor expressions in prepubertal female rats. Method: MET (1, 10 and 100 mg/kg/day) was administered daily from postnatal day 25 (PND 25) through the PND 34, and the animals were sacrificed on the PND 35. The first V.O. day was monitored, and the weights of reproductive tissues were measured. To assess the structural alterations in the ovary and uterus, the tissues were embedded in paraffin and stained for histological analysis. The transcriptional activities of hypothalamic and pituitary genes were measured using quantitative RT-PCRs. The uterine and hypothalamic proteins were extracted and used for the ER western blotting. Results: As a result, 100 mg group showed advanced V.O. than control, 1 mg group and 10 mg group. The wet weights of ovaries from MET-treated animal dose-dependently increased. The uterine weights were increased in 1 mg group and 10 mg group, while the 100 mg group samples were not significantly different from control tissues. The adrenal, kidney, spleen and thymus weights were not shown any significant change. Corpora lutea and fully grown follicles were observed in the ovaries from the 100 mg group, while numerous primary and secondary follicles were observed in the ovaries from control group. Myometrial thickness of MET-treated group was dose-dependently increased. Epithelial hypertrophy and well-developed glands were observed in the uterus from the 10 mg groups. Conclusions: The present study demonstrated that the short-term exposure to MET during the critical period of prepubertal stage could activate a reproductive endocrine system, resulting the early onset of puberty in immature female rats. Our study suggests that MET’s disrupting effect might be derived from premature activation of key reproduction-related genes in hypothalamus-pituitary neuroendocrine circuit.

6-hydroxydopamine(6-OHDA)는 파킨슨 질환 동물 모델의 제조에 널리 사용되는 신경독소로 도파민성 뉴런에 대한 특이적인 독성을 나타낸다. 도파민 신호는 중추신경계의 광범위한 영역에서 생리 기능을 조절하는데, 이에 따라 파킨슨병 환자와 6-OHDA를 처리한 동물들의 신경내분비 활성에 극심한 변화가 있을 것으로 예상할 수 있다. 하지만 6-OHDA 주사 모델에서 시상하부-뇌하수체 신경내분비 회로에 관한 연구들은 전무한 실정이다. 본 연구는

Vinclozolin (VCZ)은 침투성 살균제로써 과일, 채소, 와인산업에 널리 사용된다. VCZ와 그것의 대사산물들인 butenoic acid (M1)과 enanilide (M2)는 안드로겐 수용체를 놓고 항 안드로겐 물질로 작용한다. VCZ가 수컷의 생식생리와 병리에서 내분비계 장애물질(endocrine disrupting chemical, EDC)로 작용함에 대한 증거는 많이 있지만, 암컷 생식생리에 미치는 VCZ의 효과에 대한 증거는 전무하다.