• Journal of Veterinary Clinics
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• v.33 no.2
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• pp.138-141
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• 2016

The aim of this study was to diagnose the fertility of a female western lowland gorilla kept in Seoul Zoo, in accordance with age by analyzing the fecal sex hormone metabolites. The study was conducted in two period of times, when the animal was from 35 to 37 years old and when the animal was from 40 to 42 years old. Non-invasive method by using fecal samples was used for safe and efficient fertility diagnosis. We collected the feces from the enclosure at least three times a week. Then $17{\beta}$-estradiol and progesterone, which are fecal sex hormone metabolites, were measured by time-resolved fluoro-immunoassay to compare the menstruation cycle and the annual reproductive cycle. For the duration of the primary study (when the animal was 35~37 years old), irregular menstruation and high concentrations of estradiol and progesterone were observed. However, menstruation was hardly observed and the concentrations of both hormones were statistically very low in the period of secondary study (when the animal was 40~42 years old). This observed phenomenon in our study was very comparable to menopause in adult women; therefore, it was confirmed that our female gorilla has reached menopause because of the natural aging, as they become older.

• Korean Journal of Biological Psychiatry
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• v.12 no.2
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• pp.173-180
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• 2005

Purpose:We investigated the effect of menopausal duration on cognitive function using adjunctive hormone replacement therapy(HRT) in postmenopausal women with depression. Method:Twelve postmenopausal women with depressive disorder were enrolled. Six patients having menopausal duration of less than 3 years was assigned to the short duration group and six patients of more than 3 years to the long duration group. Each patient was treated with conjugated equine estrogen(1.25mg) plus medroxyprogesterone(5mg) for 8 weeks. Cognitive performance was measured by the Verbal Memory Test, Visual Memory Test, Trail Making Test, Digit Symbol Test, and Attention Shift Test. The Beck Depression Inventory was used for evaluation of depressed mood. The reproductive hormone levels were also measured. Results:The long duration group showed the lower performance only in Trail Making Test B compared with the short duration group at baseline. After 8 weeks, the long duration group performed significantly better in the Trail Making Test B compared with the short duration group. The differences in change of depressive mood and gonadal hormone level between two groups were not significant. Conclusion:Menopausal duration before HRT may influence the effect of estrogen on cognition in some cognitive domains. This might be related with estrogen receptor hypersensitivity which induced by the longer estrogen deficiency.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.3
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• pp.309-314
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• 2023

Shark populations are constantly decreasing owing to environmental destruction and overfishing; thus, sharks are now at risk of extinction, with 30.5% of species classified as endangered on the International Union for Conservation of Nature's Red List. Sharks are apex predators and keystone species in balancing the marine food chain; their extinction would create an imbalance in the entire marine ecosystem. Assisted reproductive technology is a last resort for protecting animals facing extinction. Here, as a proactive effort toward building a hormone-induced artificial insemination protocol for endangered wild sharks, we identified the possibility of germ cell maturation by administration of GnRH, a commercially produced synthetic salmon gonadotropin-releasing hormone, and calculated its optimum dosage and injection timing. The experiment was conducted on one shark species, Chiloscyllium plagiosum. Injections were administered in 24 h intervals to C. plagiosum females, and 0.2 mL/kg+0.2 mL/kg were the optimal doses. These doses effectively induced maturation and, and ovulation, and oocyte release. Our results confirm that GnRH is a suitable tool for shark hormone-induced artificial insemination and indicate that this method may facilitate the conservation of endangered shark species.

• Safety and Health at Work
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• v.2 no.3
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• pp.290-300
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• 2011

Objectives: There is limited data regarding the toxicity of methylcyclohexane, despite its wide use in rubber adhesives, paint diluents, and cleansing agents. This study aimed to verify the toxicity and influence on the reproductive system of methylcyclohexane after its repeated injection in Sprague Dawley (SD) rats. Methods: Methylcyclohexane was injected subcutaneously into male and female SD rats once a day, five times a week, for 13 weeks at different doses (0, 10, 100, and 1,000 mg/kg/day) for each group. The toxicity of testing material was verified by observing the change in body and organ weight, hematological change, pathological findings, and effect on the reproductive system at each different concentration. Results: In the 1,000 mg/kg/day group, there were cases of animal deaths. In animals that survived, hematological changes, including a decrease in the red blood cell count, were observed. A considerable weight gain or loss and pathological abnormalities in the liver, kidney, and other organs were found. However, the 10 and 100 mg/kg/day groups did not cause deaths or other specific abnormalities. In terms of reproductive toxicity, there were changes in hormone levels, including a significant decrease in hormones such as estradiol and progesterone (p < 0.001) in male animals. Menstrual cycle change for female animals did not show concentration dependency. Conclusion: When injected repeatedly for 13 weeks, methylcyclohexane proved to be toxic for the liver, heart, and kidney at a high dose. The absolute toxic dose was 1,000 mg/kg/day, while the no observed adverse effect level was less than 100 mg/kg/day. The substance exerted little influence on the reproductive system.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.8_spc
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• pp.1284-1295
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• 2019

Considerable progress in reproduction of dairy goats has been made, with advances in reproductive technology accelerating dairy goat production since the 1980s. Reproduction in goats is described as seasonal. The onset and length of the breeding season is dependent on various factors such as breed, climate, physiological stage, male effect, breeding system, and photoperiod. The reproductive physiology of goats was investigated extensively, including hypothalamic and pituitary control of the ovary related to estrus behavior and cyclicity etc. Photoperiodic treatments coupled with the male effect allow hormone-free synchronization of ovulation, but the kidding rate is still less than for hormonal treatments. Different protocols have been developed to meet the needs and expectations of producers; dairy industries are subject to growing demands for year round production. Hormonal treatments for synchronization of estrus and ovulation in combination with artificial insemination (AI) or natural mating facilitate out-of-season breeding and the grouping of the kidding period. The AI with fresh or frozen semen has been increasingly adopted in the intensive production system, this is perhaps the most powerful tool that reproductive physiologists and geneticists have provided the dairy goat industry with for improving reproductive efficiency, genetic progress and genetic materials transportation. One of the most exciting developments in the reproduction of dairy animals is embryo transfer (ET), the so-called second generation reproductive biotechnology following AI. Multiple ovulation and ET (MOET) program in dairy goats combining with estrus synchronization (ES) and AI significantly increase annual genetic improvement by decreasing the generation interval. Based on the advances in reproduction technologies that have been utilized through experiments and investigation, this review will focus on the application of these technologies and how they can be used to promote the dairy goat research and industry development in the future.

• Development and Reproduction
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• v.13 no.4
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• pp.207-215
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• 2009

Numerous factors can affect the activities of hypothalamus-pituitary-gonad (HPG) hormonal axis, resulting in alteration of reproductive capacity or status such as onset of puberty and menopause. Soon after the finding of leptin, a multifunctional hormone secreted from adipocytes, a close relationship between reproduction and body energy balance have been manifested. Ghrelin, another multifunctional hormone from gastrointestinal tract, is an endogenous ligand of growth hormone secretagogue receptor (GHSR), and is thought to be a counterpart of leptin in the regulation of energy homeostasis. As expected, ghrelin can also modulate the reproductive capacity through the modulation of activities of HPG axis. This paper summarizes the current knowledge on the discovery, gene structures, tissue distribution and roles of ghrelin and GHSRs in mammalian reproduction in particular modulation of reproductive hormone secretion in HPG axis. Like POMC gene expression in pituitary gland, preproghrelin gene can generate a complex repertoire of transcripts which further undergo alternative splicing and posttranslational modifications. Concerning the roles of preproghrelin gene products in the control of body physiology except energy homeostasis, limited knowledge is available so far. Several lines of evidence, however, show the interplay of ghrelin between metabolism and reproduction. In rat and human, the distribution of ghrelin receptor GHSRs (GHSR1a and GHSR1b) has been confirmed not only in the hypothalamus and pituitary which were originally postulated as target of ghrelin but also in the testis and ovary. Expression of the preproghrelin gene in the brain and gonads was also verified, suggesting the local role (s) of ghrelin in HPG axis. Ghrelin might play a negative modulator in the secretions of hypothalamic GnRH, pituitary gonadotropins and gonadal steroids though the action on pituitary is still questionable. Recent studies suggest the involvement of ghrelin in regulation of puberty onset and possibly of menopause entry. It is now evident that ghrelin is a crucial hormomal component in 'brain-gut' axis, and is a strong candidate links between metabolism and reproduction. Opposite to that for leptin, ghrelin signaling is likely representing the 'hunger' state of body energy balance and is necessary to avoid the energy investment into reproduction which has not a top priority in maintaining homeostasis. Further researches are needed to gain a deep insight into the more precise action mechanism and role of ghrelin in reproduction, and to guarantee the successful biomedical applications.

• Korean Journal of Animal Reproduction
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• v.7 no.1
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• pp.41-51
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• 1983

The purpose of this experiment was to investigate the effects of adrenalectomy and PMSG treatment on reproductive organs and serum steroid hormone level in immature female rats. The animals used in this experiment were 25 days old female rats weighing a, pp.oximately 70g. They were randomly divided into two groups of intact rat group (Int-) and adrenalectomized rat group (Adx-) and each group were subdivided into two groups of Non-PMSG (-Cont) and PMSG treated (-PMSG) group. The rat of PMSG-treated group (-PMSG) was administered subcutaneously with 25 IU PMSG on first day (9 a.m.) after adrenalectomy. The adrenalectomized rat groups were su, pp.ied with saline solution through the experiment period. The rate of ovulation and vaginal opening and reproductive organ weights were observed at 8, 32, 56, 80 and 104 hours after PMSG treatment. At the same time, the serum level of estradiol-17${\beta}$ and progesterone were measured by the radioimmunoassay. The results obtained were as follows: 1. Ovulation was shown at 56 hours after treatment in Int-PMSG group and Adx-PMSG group and Adx-PMSG group. The rate of ovulation was very low in PMSG-treated groups, but it was increased in 80 to 90% at 104 hours after treatment. However, there was no ovulation in Int-Cont group and Adx-Cont group. 2. Vaginal opening was shown at 56 hours after treatment in Int-PMSG group and Adx-PMSG group and a, pp.ared in 80% at 104 hours after treatment. The rate of vaginal opening in PMSG-treated groups was very low, but Int-Cont group and Adx-Cont group had no vaginal opening. 3. The weight of ovary and uterus in two PMSG-treated groups were increased with the elapse of time after treatment and were significantly heavy in all observation time, but changes in Int-Cont group and Adx-Cont group were not recognized. The weights of ovaries and utera in Adx-Cont group were increased with the elapse of time. 4. The level of serum estradiol-17${\beta}$ was remarkably increased in PMSG-treated groups (Int-PMSG and Adx-PMSG groups) compared with Int-Cont and Adx-Cont group, and significant difference was recognized between Non-PMSG group and PMSG-treated group in the experimental period. Especially, the highest levels of Int-PMSG groups and Adx-PMSG groups were shown at 80 and 56 hours after treatment and after ward estradiol-17${\beta}$ levels of PMSG-treated groups were decreased. However, changes of the levels did not a, pp.ared in Non-PMSG groups at 104 hours after treatment. 5. The level of serum progesterone in PMSG-treated groups was significantly increased between 80 and 104 hours after treatment. With the elapse of time, the level was increased in all observed groups except for Int-Cont and Adx-Conx group. And the order from the highest level at 104 hours after treatment was Int-PMSG, Adx-PMSG, Int-Cont and Adx-Cont group.

• Development and Reproduction
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• v.13 no.3
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• pp.183-190
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• 2009

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 $32.8{\pm}0.37$ p<0.001) compared to the control (PND $38.25{\pm}0.25$). 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.

• BMB Reports
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• v.48 no.5
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• pp.241-242
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• 2015

Reproductive behaviors have evolved through severe inter-sexual competition. We have recently described a behavior in post-mated female Drosophila melanogaster that controls ejaculate retention and sperm storage, and is a possible mechanism by which females who have mated with several partners can choose which sperm that is stored and used for fertilization. This behavior can also regulate exposure of the female to harmful effects of male SFP that are present in the ejaculate. Our study identified the neural pathway functioning in the female brain that regulates this behavior. [BMB Reports 2015; 48(5): 241-242]

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.83-90
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• 2000