본 연구에서는 GnRH가 과배란 처치된 래트의 초기 난포기와 후기 난포기에서 난소기능에 어떠한 영향을 미치는지를 이해하기 위해서, 30IU PMSG와 10IU hCG로 전처치된 미성숙 래트에 있어서 배란반응, 배란 난자의 형태학적 이상 유무 및 핵 성숙도, 난소 중량, 난소의 조직학적인 변화 및 혈중 스테로이드 호르몬 (17-estradiol, progesterone 및 testosterone) 농도에 대하여 GnRH agonist의 효과를 검사하였다.

The present work was designed to understand the mechanism of superovuiation and the cause of early embryo loss and Implantation failure in the superovulating immature female rats which were elaborated by a pituitary gland transplantation. A pituitary gland obtained from the orchidectomized rats was transplanted under the right kidney capsule of 28 day old female rats (PGT group) on the starting day of experiment which was designated as Day 2. The grafted pituitary glands were removed at 6h (RPGT 6h group), 12h (RPGT 12hgroup) and 24h (RPGT 24h group) after the transplantation. Control rats were treated with 41U PMSG on Day 2 (PMSG group). The estrous cycle and the levels of plasma progesterone and estradiol-17 were observed on Day 0, Day 5, respectively. The implantation sites, the weights of ovary and uterus, and the number of corpora lutea were examined in all group on Day 8. The resuft obtained were summarized as follows: 1. The percentages of the number of the rats in proestrus and estrus were 93.0%, 82.6%, 0%, 90.7% and 89.5% in PMSG, PGT, RPGT6h, RPGT12h and RPGT24h group, respectively. The synchronization of estrus cycle was dchieved in all groups. 2. The mating rates of each group were 80.2, 75.0, 0, 56.4, 57.8% in PMSG, PGT, RPGT6h, RPGT12h, RPGT24h group, respectively. 3. The numbers of copora lutea on Day 8 were 47.1 i 4.9, 18.1 0.5, 14.1 i 0.3 and 8.9 0.3 in PGT, RPGT24h, RPGTl2h and PMSG group, respectively. There were signIficantly difference between all groups (P<0.05). 4. The numbers of implantation sites (18.1 +- 4.0) in PGT group on Day 8 were higher than those of PMSG (8.5 2.5), RPGT 12h (9.8 i 0.2) and RPGT 24h group (10.8 i 0.2) (P<0.05). 5. The ovarlan weights in PGT (95.2 14.3mgIlOOg BW), RPGT 12h (51.7 0.6mgIlOOg BW), and RPGT24h (57.9 0.9mg/l00g 8W) groups were significantly higher than those of PMSG group (30.4 7.4mg/l00g BW) (P<0.05). 6. The uterine weights in PMSG (672.4 4.7mg/l00g 8W), and PGT (660.7 7.8mg/l00g BW) groupswere greater than those of RPGT 12h (403.0 1.lmg/lOOg BW) and RPGT 24h (490.1 0.9mg/l00g BW) group (P<0.05). 7. The plasma progesterone levels in PGT groups (15 lng/ml) on Day 5 were higher than those of PMSG (83ng/ml), RPGT 12h (S7ng/ml), RPGT24h (8lng/ml) group (P<0.05). 8. The plasma estradiol-17 levels in PMSG group (lBSpg/ml) on Day S were higher than those of RPGT 24h (l3pg/ml) group (P<0.05). But estradiol-17 levels in PGT and RPGT 12h group were too low to discuss.

부신(副腎)의 기능(機能)이 생식기관(生殖器官)에 미치는 영향(影響)을 구명(究明)코자 21일령(日齡)의 암흰쥐(體重(체중): ) 210마리를 정상(正常)흰쥐실험군(實驗群)(이하(以下) Int.-)과 부신척출실험군(副腎剔出實驗群)(이하(以下) Adx.-)으로 나누고, 각군(各群)을 다시 대조군(對照群)(이하(以下)-Cont.), PMS 투여군(投與群)(이하(以下) - PMS) 및 PMS와 cortisol의 병용투여군(이하(以下)-PMS+corti)의 3개군(個群)으로 나누어 35마리씩 배치(配置)한 다음 부신척출실험군(副腎剔出實驗群)에 대(對)하여 부신척출(副腎剔出)을 실시(實施)한 5일후(日後)(흰쥐 일령(日齡) : 26일(日))에 PMS투여군(投與群)에는 마리당 25IU의 PMS를, PMS와 Cortisol의 병용투여군에는 마리당 25IU의 PMS와 의 Cortisol의 처리후(處理後) 48, 54, 60, 66, 72, 78 및 84시간(時間)에 5마리씩 도살(屠殺)하여 생식기능(生殖機能)의 중량(重量)을 측정(測定)하였다. 1. 난소(卵巢)의 중량(重量)은 모든 처리군(處理群)이 처리후(處理後) 기간(期間)이 경과(經過)할수록 증가(增加)하여 전관찰시간(全觀察時間)에서 비교군간(比較群間)에 고도(高度)의 유의성(有意性)(P<0.01)이 인정(認定)되었으나 대조군(對照群)인 Int.-Cont. 군(群)과 Adx.-Cont. 군(群)은 변화(變化)가 인정(認定)되지 않았다. 다중검정결과(多重檢定結果) 부신(副腎)을 척출(剔出)한 Adx.-PMS군(群)과 Adx.-PMS+Corti. 군(群)은 정상(正常)흰쥐 실험군(實驗群)인 Int.-PMS군(群)과 Int.-PMS+Corti. 군(群)에 비하여 유의(有意)(P<0.05)하게 낮은 값을 보였고, Cortisol 투여(投與)에 따른 효과(效果)는 인정(認定)되지 않았다. 2. 자궁(子宮)의 중량(重量)은 모든 관찰시간(觀察時間)에서 비교군간(比較群間)에 고도(高度)의 유의성(有意性)(P<0.01)이 인정(認定)되었는데, 처리후(處理後) 66시간(時間)까지는 정상(正常)흰쥐 실험군(實驗群)인 Int.-PMS군(群)과 Int.-PMS+Corti.군(群)이 높은 값을 보였고, 72시간(時間) 후(後)부터는 반대(反對)로 부신척출실험군(副腎剔出實驗群)인 Adx.-PMS군(群)과 Adx.-PMS+Corti.군(群)이 높은 값을 나타냈으며, 다중검정결과(多重檢定結果) Int.-PMS군(群)과 Int.-PMS-Corti.군(群), 그리고 Adx.-PMS군(群)과 Adx.-PMS군(群)과 Adx.-PMS+Corti.군(群) 상호간(相互間)에는 유의성(有意性)이 인정(認定)되지 않았다. 3. 정상(正常)흰쥐 실험군(實驗群)에서의 부신(副腎)의 중량(重量)은 Int.-PMS 군(群)에서 근소(僅少)하게 높은 값을 나타냈으나 비교군간(比較群間)에는 통계적(統計的)인 유의성(有意性)은 인정(認定)되지 않았고, 조직소견(組織所見)에서도 특기(特記)할 만한 변화(變化)를 인지(認知)할 수 없었다.

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.

Background & Objectives : Nonylphenol (NP), a member of alkylphenols, has been widely used in manufacturing antioxidants, The present study was undertaken to examine whether short-term exposure to NP can alter the onset of puberty and associated reproductive parameters such as hormone receptor expressions in prepubertal female rats. Methods : NP (0.1, 1, 10 mg/kg BW) was administered orally at 10:00 from postnatal day 25 (PND 25) through the PND 35. The control group was administered orally each day 200 uL of the sesame oil. At PND 36, all groups were sacrificed at 18:00. The first vaginal opening (V.O.) day was monitored, and the weights of reproductive tissues were measured. Ovaries and uteri were used for analysis of mRNA levels, protein levels and histology. The transcriptional activities of the ovaries (StAR, P405scc, 3β-HSD, 17β-HSD, Aromatase and LH-R) and uteri(ER) were measured using quantitative RT-PCRs. The uterine proteins were used for the ER western blotting. Histological analysis of the reproductive organs was carried out. Results: Administration of NP induced early V.O. when compared to control. The ovarian weights of 1 mg group (0.164±0.010 mg/g BW) was significantly higher than those of control group (0.116±0.007 mg/g BW). Among the steroidogenesis-related genes, mRNA levels of the ovarian P450scc, 3β-HSD and Aromatase are increased significantly in all NP-treated groups. The mRNA levels of StAR and 17β- HSD were unchanged. NP administration (1 mg group) significantly increased the LH-R transcript level. Among the steroid hormone receptor genes, the mRNA level of ER-alpha was significantly elevated in 1mg NP group, while the mRNA levels of ER-beta and PR were unchanged in all NP-treated groups. Interestingly, wetern blotting data for uterine steroid hormone receptors revealed the complete disagreement with the transcriptional activities. Histological status of ovaries and uteri also exerted the occureence of advanced maturation in NP-treated groups. Conclusion: The present study demonstartes that the short-term administration of NP accelerates V.O. and maturation of reproductive organs such as ovary and uterus.

Lipopolysaccharide (LPS), an endotoxin, elicits strong immune responses in mammals. Several lines of evidence demonstrate that LPS challenge profoundly affects female reproductive function. For example, LPS exposure affects steroidogenesis and folliculogenesis, resulting in delayed puberty onset. The present study was conducted to clarify the mechanism underlying the adverse effect of LPS on the delayed puberty in female rats. LPS was daily injected for 5 days (50 μg/kg, PND 25-29) to treated animals and the date at VO was evaluated through daily visual examination. At PND 39, animals were sacrificed, and the tissues were immediately removed and weighed. Among the reproductive organs, the weights of the ovaries and oviduct from LPS-treated animals were significantly lower than those of control animals. There were no changes in the weights of uterus and vagina between the LPS-treated and their control animals. Immunological challenge by LPS delayed VO. Multiple corpora lutea were found in the control ovaries, indicating ovulations were occurred. However, none of corpus luteum was present in the LPS-treated ovary. The transcription level of steroidogenic acute regulatory protein (StAR), CYP11A1, CYP17A1 and CYP19 were significantly increased by LPS treatment. On the other hand, the levels of 3β- HSD, 17β-HSD and LH receptor were not changed by LPS challenge. In conclusion, the present study demonstrated that the repeated LPS exposure during the prepubertal period could induce multiple alterations in the steroidogenic machinery in ovary, and in turn, delayed puberty onset. The prepubertal LPS challenge model used in our study is useful to understand the reciprocal regulation of immune (stress) - reproductive function in early life.

Manganese () is a trace element that is essential for normal physiology, and is predominantly obtained from food. Several lines of evidence, however, demonstrated that overexposure to exerts serious neurotoxicity, immunotoxicity and developmental toxicity, particularly in male. The present study aimed to evaluate the effect of 0, 1.0, 3.3, and 10 mg/kg/day doses of on the reproductive organs in the immature female rats. Rats (PND 22; S.D. strain) were exposed to () dissolved in drinking water for 2 weeks. The animals were sacrificed on PND 35, then the tissues were immediately removed and weighed. Histological studies were performed using the uteri tissue samples. Serum LH and FSH levels were measured with the specific ELISA kits. Body weights of the experimental group animals were not significantly different from those of control group animals. However, ovarian tissue weights in 1 mg and 3.3 mg dose groups were significantly lower than those of control animals (p<0.05 and p<0.01, respectively). Uterine tissue weights of 3.3 mg dose groups were significantly lower than those of control animals (p<0.01), while the 1 mg dose and 10 mg dose failed to induce any change in uterine weight. Similarly, only 3.3 mg dose could induce the significant decrease in the oviduct weight compared to the control group (p<0.05). Non-reproductive tissues such as adrenal and kidney failed to respond to all doses of exposure. The uterine histology revealed that the exposure could affect the myometrial cell proliferation particularly in 3.3 mg dose and 10mg dose group. Serum FSH levels were significantly decreased in 1mg dose and 10 mg groups (p<0.05 and p<0.01, respectively). In contrast, treatment with 1 mg dose induced a significant increment of serum LH level (p<0.05). The present study demonstrated that exposure is capable of inducing abnormal development of reproductive tissues, at least to some extent, and altered gonadotropin secretions in immature female rats. Combined with the well-defined actions of this metal on GnRH and prolactin secretion, one can suggest the might be a potential environmental mediator which is involved in the female pubertal process.

In mammals, puberty is a dynamic transition process from infertile immature state to fertile adult state. The neuroendocrine aspect of puberty is started with functional activation of hypothalamus-pituitary-gonadal hormone axis. The timing of puberty can be altered by many factors including hormones and/or hormone-like materials, social cues and metabolic signals. For a long time, attainment of a particular body weight or percentage of body fat has been thought as crucial determinant of puberty onset. However, the precise effect of high-fat (HF) diet on the regulation of hypothalamic GnRH neuron during prepubertal period has not been fully elucidated yet. The present study was undertaken to test the effect of a HF diet on the puberty onset and hypothalamic gene expressions in immature female rats. The HF diet (45% energy from fat, HF group) was applied to female rats from weaning to around puberty onset (postnatal days, PND 22-40). Body weight and vaginal opening (VO) were checked daily during the entire feeding period. In the second experiment, all animals were sacrificed on PND 36 to measure the weights of reproductive tissues. Histological studies were performed to assess the effect of HF diet feeding on the structural alterations in the reproductive tissues. To determine the transcriptional changes of reproductive hormone-related genes in hypothalamus, total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). Body weights of HF group animals tend to be higher than those of control animals between PND 22 and PND 31, and significant differences were observed PND 32, PND 34, PND 35 and PND 36 (p<0.05). Advanced VO was shown in the HF group (PND p<0.001) compared to the control (PND ). The weight of ovaries (p<0.01) and uteri (p<0.05) from HF group animals significantly increased when compared to those from control animals. Corpora lutea were observed in the ovaries from the HF group animals but not in control ovaries. Similarly, hypertrophy of luminal and glandular uterine epithelia was found only in the HF group animals. In the semi-quantitative RT-PCR studies, the transcriptional activities of KiSS-1 in HF group animals were significantly higher than those from the control animals (p<0.001). Likewise, the mRNA levels of GnRH (p<0.05) were significantly elevated in HF group animals. The present study indicated that the feeding HF diet during the post-weaning period activates the upstream modulators of gonadotropin such as GnRH and KiSS-1 in hypothalamus, resulting early onset of puberty in immature female rats.

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.

Dicarboximide계 살균제인 vinclozolin(VCZ)은 과일, 야채, 관상용 식물에서 미생물에 의해 유발되는 병들을 통제하는데 사용되어왔다. VCZ의 대사산물인 M1과 M2는 흔히 토양, 식물, 포유류에 잔존하기 때문에 인간에게 노출될 가능성이 크다. VCZ가 갖는 항안드로겐성 활성 때문에 주로 수컷에 대한 연구가 이루어졌으며, 암컷의 사춘기와 생식계에 미치는 영향은 연구가 미비한 실정이다. 따라서 본 연구는 VCZ가 암컷 흰쥐의 사춘기 개

일부 식물성 에스트로겐(phytoestrogen)의 경우, 긍정적인 효과를 갖는 것으로 보이지만, 대부분의 내분비계 장애 물질(endocrine disruptor 또는 endocrine disrupting compound, EDC)은 노출된 개체의 내분비계를 교란시켜 인간이나 야생 동물의 건강에 해로운 것으로 알려져 있다. 선행 연구에서 본 연구자들은 사춘기 전에 단기간으로 식물성 에스트로겐인 genistein(GS)을 투여했을 때 암컷 흰쥐의 생식계가