• Development and Reproduction
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• v.5 no.1
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• pp.1-8
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• 2001

Golden hamsters show the reproductive activity that is determined by the photoperiod (length of light per day). Photoperiod is an environmental factor that is predictable through an entire year. The hamsters are sexually active in summer during which day length exceeds night time. The critical length is at least 12.5 hours of light in a day where reproductive function is maintained. The information of photoperiod is mediated by the pineal gland because removal of pineal gland blocks the influence of photoperiod on reproductive activity. The hamsters without pineal gland maintain sexual activity and promote it in a situation that suppresses gonadal activity. The pineal gland secretes melatonin that reflects the photoperiod. The appropriate administrations of melatonin into both pineal intact and pinealectomized hamsters lead to a gonadal reression. The results suggest that melatonin constitutes a part of control mechanism whereby environmental information is transduced to neuroendocrine signal respensible for the functional integrity of the reproductive system. Despite of the intense studies, the action site of melatonin is on the whole unknown. It is mainly due to the lack of acute efffct of melatonin on the secretion of reproductive hormones. However, sexually regressed animals display the low levelsof gonadotropins and the augmentation of the hypothalamic gonadotropin-releasing hormone (GnRH) content, implying that the antigonadotropic effects either by photoperiod and/or by the treatment of melatonin are mediated by the GnRH neuronal system. The action mechanism by which melatonin exerts its effect on GnRH neuron needs to be investigated. Recent cloning of melatonin receptor will contribute to examine various and putative potencies of melatonin via its anatomical identification and the action mechanism of melatonin on target tissues at the molecular level.

• Journal of Ginseng Research
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• v.14 no.2
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• pp.162-166
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• 1990

The climacterium is that phase in the aging precess during which a woman passes from the reproductive to the non-reporductive stage. The signals, such as hot flashes, vaso-motoric disturbances, perspiration, stiff shoulders, emotinal symptoms, are refered to as climacteric disturbances. Treatment of climacteric symptoms centers around estrogen replacement and transfuilizers, but there are many problems to be solved to use these hormones/drugs as far as dossage, duration and complications are concerned. The care of women during the climacteric years should provide relief of distressing symptoms with as high a degree of safety as possible. From this view point, we used red ginseng powder to those patients with high menopausal index successfully. We studied its mechanism of action and proved that red ginseng improved the micro-circulation system via improvement of erythrocyte reformability which enhanced sex steroidgensis consequently.

• BMB Reports
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• v.44 no.6
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• pp.393-398
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• 2011

Polydnaviruses are a group of double-stranded DNA viruses and are symbiotically associated with some ichneumonoid wasps. As proviruses, the replication of polydnaviruses occurs in the female reproductive organ at the pupal stage. This study analyzed the effects of two developmental hormones, juvenile hormone (JH) and ecdysteroid, on the viral replication of Cotesia plutellae bracovirus (CpBV). All 23 CpBV segments identified contained a conserved excision/rejoining site ('AGCTTT') from their proviral segments. Using quantitative real-time PCR based on this excision/rejoining site marker, initiation of CpBV replication was determined to have occurred on day 4 on the pupal stage. Pyriproxyfen, a JH agonist, significantly inhibited adult emergence of C. plutellae, whereas RH5992, an ecdysteroid agonist, had no inhibitory effect. Although RH5992 had no effect dose on adult development, it significantly accelerated viral replication. The results of immunoblotting assays against viral coat proteins support the effects of the hormone agonists on viral replication.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.122-122
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• 2003

Endometrial tissue is an interesting model for intrinsic and extrinsic factors, ie hormones and growth factors, involved in its normal pathologic development and its cyclic growth. The endometrial cells were isolated from endometrial tissue of the proliferative phase obtained by hysterectomy and separated stromal and epithelial cells.(omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.158.1-158.1
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• 2003

Carbofuran(CF) is one of the most widely used carbamate pesticides in the world applied for insect and nematode control. Due to its widespread use in agriculture and households, contamination of food, water, and air has become serious, and consequently adverse health effects are inevitable in humans, animals, wildlife and fish, it has reported that CF alone or in combination with other carbamate insecticides influences the level of reproductive and metabolic hormones such as thyroxine and corticosterone, and results in impairment of endocrine, immune behavioral functions. (omitted)

• Journal of Embryo Transfer
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• v.28 no.2
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• pp.157-162
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• 2013

Methoxychlor (MXC) was developed to be a replacement for the banned pesticide DDT. HPTE [2,2-bis (p-hydroxyphenyl)-1,1,1-trichloroethane], which is an in vivo metabolite of MXC, has strong oestrogenic and anti-androgenic effects. MXC and HPTE are thought to produce potentially adverse effects by acting through oestrogen and androgen receptors. Of the two, HPTE binds to sex-steroid receptors with greater affinity, and it inhibits testosterone biosynthesis in Leydig cells by inhibiting cholesterol side-chain cleavage enzyme activity and cholesterol utilisation. In a previous study, MXC was shown to induce Leydig cell apoptosis by decreasing testosterone concentrations. I focused on the effects of MXC on male mice that resulted from interactions with sex-steroid hormone receptors. Sex-steroid hormones affect other organs including the kidney and liver. Accordingly, I hypothesised that MXC can act through sex-steroid receptors to produce adverse effects on the testis, kidney and liver, and I designed our experiments to confirm the different effects of MXC exposure on the male reproductive system, kidney and liver. In these experiments, I used pre-pubescent ICR mice; the puberty period in ICR mice is from postnatal day (PND) 45 to PND60. I treated the experimental group with 0, 100, 200, 400 mg MXC/kg b.w. delivered by an intra-peritoneal injection with sesame oil used as vehicle for 4 weeks. At the end of the experiment, the mice were sacrificed under anaesthesia. The testes and accessory reproductive organs were collected, weighed and prepared for histological investigation. I performed a chemiluminescence immune assay to observe the serum levels of testosterone, LH and FSH. Blood biochemical determination was also performed to check for other effects. There were no significant differences in our histological observations or relative organ weights. Serum testosterone levels were decreased in a dose-dependent manner; a greater dose resulted in the production of less testosterone. Compared to the control group, testosterone concentrations differed in the 200 and 400 mg/kg dosage groups. In conclusion, I observed markedly negative effects of MXC exposure on testosterone concentrations in pre-pubescent male mice. From our biochemical determinations, I observed some changes that indicate renal and hepatic failure. Together, these data suggest that MXC produces adverse effects on the reproductive system, kidney and liver.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.2
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• pp.226-233
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• 2010

Different dietary cereal sources and fat types in the lactation diet were evaluated to investigate their effects on reproductive performance, milk composition, blood metabolites and hormones in multiparous sows. Twenty-four sows were randomly assigned to one of four treatments according to a 2${\times}$2 factorial arrangement of treatments. Each treatment had 6 replicates comprising 1 sow. Two cereal (corn or wheat) and two fat (tallow or soybean oil) sources were used to prepare iso-caloric and iso-nitrogenous diets. Sows fed corn-based diets lost less body weight (p = 0.003) and backfat thickness (p = 0.034), consumed more feed (p = 0.032) and had shorter wean-to-estrus interval (p = 0.016) than sows fed wheat-based diets. Fewer piglets and lower body weight of piglets (p<0.05) at weaning were noted in sows fed wheat-based diets than in sows fed corn-based diets. However, no significant effects (p>0.05) of dietary fat source and its interaction with dietary cereal source on sow body condition and reproductive performance were observed during lactation. Feeding of a corn-based diet improved (p<0.05) sow milk total solid, protein and fat, increased blood urea nitrogen (p = 0.032) and triglyceride (p = 0.018), and decreased blood creatinine (p = 0.011) concentration at weaning when compared with sows fed wheatbased diets. Sows fed corn-based diets had higher concentration of insulin (p = 0.048) and LH (p<0.05) at weaning than sows fed wheatbased diets. The results indicate that feeding corn-based diets to lactating sows improved sow body condition and reproductive performance compared with wheat-based diets regardless of fat sources.

• Journal of Embryo Transfer
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• v.21 no.1
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• pp.29-34
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• 2006

본 연구는 개 체외성숙 난자를 안정적으로 생산하기 위하여 채취시기, 난구세포 부착 여부 및 배양액에 EGF와 호르몬을 첨가 후 배양했을 때 체외성숙율에 미치는 영향을 조사하였다. 1. 미성숙 난포란을 TCM-199 배양액에서 24, 45시간 배양했을 때 체외성숙율은 각각 7.93%, 8.94%로서 48시간 배양했을 때 가장 높은 체외성숙율을 나타냈다. 2. 휴지기, 난포기, 황체기에 채취한 난소로부터 회수한 난자를 20 ng/ml의 EGF가 첨가된 TCM-199 배양액에서 배양했을 때 체외성숙율은 14.3%로서 0, 10 ng/ml의 EGF 첨가군(3.1%, 7.5%)에 비해 높은 체외성숙율을 나타냈다. 3. 난구세포 부착 및 미부착 난자를 48시간 배양했을 때 체외성숙율은 각각 18.8% 및 7.5%로서 난구세포 부착 난자가 미부착 난자보다 높은 체외성숙율을 나타냈다. 4. 난자의 체외성숙 배양 시 0.5 mg/ml FSH, 5 mg/ml LH, 1 mg/ml $E_2$와 FSH+LH, $FSH+LH+E_2$를 첨가한 TCM-199 배양액에서 배양했을 때 체외성숙율은 각각 1.2%, 10.0%, 2.0%와 10.0%, 31.2%로서 호르몬의 병용처리군이 높은 체외성숙율을 나타냈다. 5. 난자의 체외성숙 배양 시 EGF와 FSH, LH, $E_2$ 및 EGF와 FSH+LH, $FSH+LH+E_2$를 첨가한 TCM-199 배양액에서 배양했을 때 체외성숙율은 32.3%, 27.0%, 3.0%와 36.2%, 69.4%로서 EGF와 호르몬 병용 처리군이 높은 체외성숙율을 나타냈다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.701-708
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• 2011

The aim of the present study was to analyze the reductive cycle of the red marbled rockfish Sebastiscus tertius. The analysis was based on annual changes in the gonadosomatic index (GSI), the hepatosomatic index (HSI), histology of the gonadal structure, and plasma sex steroid hormone levels of adult fish from April 1997 to April 1998. GSI of females began to increase in February and peaked ($10.8{\pm}2.72$) in May. HIS levels ($3.41{\pm}0.49$) peaked in February and elevated plasma steroid hormones ($1.47{\pm}0.75$ ng/mL for estradiol-$17{\beta}$ ($E_2$) and $230.7{\pm}27.6$ pg/mL for testosterone (T)) were observed in April. However, in male fish, GSI levels started to increase in August and remained high until November ($0.21{\pm}0.05$). T levels were was also elevated in August and peaked in October ($188.1{\pm}43.5$ pg/mL) and November ($186.8{\pm}28.0$ pg/mL), but started to decline 1 month than the GSI. These results suggest that female ovoviviparious periods span from April to June and amle mating periods occur from November to February.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.4
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• pp.329-337
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• 2020

Cytochrome P450 1A2 (CYP1A2) is a member of the cytochrome P450 superfamily enzymes in mammals and plays a major role in metabolizing endogenous hormones in the liver. In recent days, CYP1A2 expression has been found in not only the liver but also other tissues including the pancreas and lung. However, little information is available regarding the expression of CYP1A2 in the ovary, in spite of the facts that the ovarian follicle growth and atresia are tightly associated with controls of endocrine hormonal networks. Therefore, the expression of CYP1A2 in the ovaries of prepubertal and pubertal rats was investigated to assess its expression pattern and puberty-related alteration. It was demonstrated that the expression level of CYP1A2 was significantly (p < 0.01) higher in the pubertal ovaries than prepubertal counterparts. At the ovarian follicle level in both groups, whereas CYP1A2 expression was less detectable in the primordial, primary and secondary follicles, the strongly positive expression of CYP1A2 was localized in the granulosa cell layers in the antral and pre-ovulatory follicles. However, the ratio of CYP1A2-positive ovarian follicle was significantly (p < 0.01) higher in the ovary of pubertal group (73.1 ± 3.1%) than prepubertal one (41.0 ± 10.5%). During the Immunofluorescence, expression of CYP1A2 was mainly localized in Fas-positive follicles, indicating the atretic follicles. In conclusion, these results suggested that CYP1A2 expression was mainly localized at the atretic follicular cells and affected by the onset of puberty. Further study is still necessary but we hypothesize that CYP1A2 expresses in the atretic follicles to metabolize residue of the reproductive hormones. These findings may have important implications for the fields of reproductive biology of animals.