• 한국수산과학회지
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• 제32권5호
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• pp.624-628
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• 1999

범가자미의 인위적인 번식제어를 목적으로 생식소 활성에 따른 혈중 vitellogenin (난황단백전구체)과 성 스테로이드 호르몬의 계절적 농도 변화를 조사하였다. 암컷에 있어서 혈중 vitellogenin의 농도는 난황축적이 활발한 11 월에 연중 최고치를 나타내다가 산란이 시작되는 12월에 감소하기 시작하면서 estradiol의 농도는 이 시기에 연중 최고치를 나타내었다(2.7ng/ml). 산란이 활발히 진행중인 1월에 혈중 estradiol 농도는 급격히 감소하여 5월까지 연중 매우 낮은 농도(0.2ng/ml)로 유지되었다. Testosterone도 estradiol과 유사한 경향을 보였다. 17$\alpha$-hydroxyprogesterone은 난소가 활성화되어 성장되는 시기를 제외하고는 뚜렷한 경향을 보이지 않았다. 수컷의 경우 testosterone과 11-ketotestosterone의 혈중농도는 12월에 최고치를 나타내었으며, 이 시기에 정자변태가 가장 활발하게 이루어지고 있음을 관찰하였다. 이후 완숙 및 방정기 (1월)에 이르러 이들의 농도는 급격히 감소하였다.

• 한국발생생물학회지:발생과생식
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• 제13권4호
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• pp.207-215
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• 2009

시상하부-뇌하수체-생식소(hypothalamus-pituitary-gonad, HPG) 호르몬 축의 활성에 영향을 미치는 수많은 인자들은 생식 기능을 조절하고, 사춘기 개시와 폐경기 진입과 같은 뚜렷한 생식 능력의 단계 전이를 초래한다. 지방세포로부터 분비되는 다기능적 호르몬인 leptin의 발견 이후, 곧 이어 생식과 신체의 에너지 균형 사이의 긴밀한 관계에 대한 증거들이 밝혀졌다. 위장관으로부터 분비되는 또 다른 다기능 호르몬인 ghrelin은 이미 알려져 있던 growth hormone secretagogue receptor(GHSR)의 내인성 리간드이며, 에너지 항상성의 조절에서 leptin에 상응하는 물질로 알려졌다. 예상대로, ghrelin 또한 HPG 축의 활성의 조절을 통해 생식 능력을 조절함이 증명되었다. 이 논문은 ghrelin의 발견과 유전자 구조, 조직 내의 분포, 그리고 역할과 HPG 축에서의 생식 호르몬 분비 조절에 대한 포유동물의 생식에서의 ghrelin-GHSR 신호에 관한 최신 정보를 요약한 것이다. 뇌하수체에서의 POMC 유전자 발현과 유사하게, preproghrelin 유전자는 alternative splicing과 번역 후 변형(posttranslational modification)을 거치는 복잡한 레퍼토리의 전사체들과 펩티드 산물을 만들어 낸다. 에너지 항상성을 제외한 신체 생리 기능의 조절에서의 preproghrelin 유전자 산물의 역할에 관한 정보는 제한적이지만, 신진 대사와 생식 사이에서의 ghrelin의 상호작용에 관해서는 충분한 증거들이 있다. 흰쥐와 인간에서, ghrelin 수용체인 GHSRs(GHSR1a와 GHSR1b)의 분포는 본래 ghrelin의 표적으로 여겨진 시상하부와 뇌하수체뿐만 아니라 정소와 난소에서도 확인되었다. 뇌와 생식소에서도 preproghrelin 유전자 발현이 확인되었는데, 이것은 HPG 축에서 ghrelin이 국부적인 역할을 담당할 가능성을 시사한다. 비록 뇌하수체에서의 기능은 아직 확실치 않지만, ghrelin은 시상하부의 GnRH, 뇌하수체의 생식소자극호르몬과 생식소의 성 스테로이드 호르몬 분비에 대한 음성적인 조절자로서의 역할을 수행하는 것으로 보인다. 최근의 연구들은 사춘기 개시, 그리고 아마도 폐경기 진입의 조절에서 ghrelin의 관여를 시사한다. 이제 ghrelin이 '뇌-위장관' 축의 필수적인 호르몬 요인이며, 신 진 대사와 생식 사이를 연결하는 조절 물질이라는 가능성은 매우 높다. '배부름'을 반영하는 leptin 신호와는 정반대인 ghrelin 신호는 신체 에너지 균형 상태로 볼 때 '배고픔'을 표현하는 것으로 생각되며, 항상성의 유지에서 최우선 사항으로 고려되지 않는 생식으로의 에너지 투자가 이루어지지 않도록 하는데 필수적일 것으로 사료된다. 생식능력 조절에 있어서 ghrelin의 보다 명확한 작용 메커니즘과 역할에 대한 깊은 통찰력을 얻고 성공적인 생의학적 적용을 위해서는 향후 더 많은 연구들이 필요하다.

• Animal cells and systems
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• 제5권4호
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• pp.327-331
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• 2001

There is a critical developmental period during which brain sexual differentiation proceeds irreversibly under the influence of gonadal hormone. Recently, kinesin superfamily-associated protein 3 (KAP3) gene expressed during the 'critical period' of rat brain differentiation was identified by us (Choi and Lee, 1999). KAP3 functions as a microtubule-based motor that transports membranous organelles anterogradely in cells, including neurons (Yamazaki et al., 1996). mRNA level of KAP3 gene markedly increased before the initiation of puberty. Neonatal treatment of estrogen clearly inhibited the prepubertal increase in KAP3 mRNA level (Choi and Lee, 1999). In the present study, we aimed to investigate the effects of polychlorinated biphenyls (PCBs), as endocrine disruptors (EDs) on the expression of KAP3 gene during the 'critical period' of rat brain development. In our data, PCBs significantly decreased the expression of KAP3 gene in the fetal (day 17) and the neonatal (day 6 after birth in) male and female rat brains. The body weight and the breeding ability were significantly decreased in the PCBs-exposed rats compared with the control. These results showed that PCBs affect the transcriptional level of brain sexual differentiation related gene, KAP3, in the fetal and the neonatal rat brains. The maternal exposure to the PCBs may lead to toxic response in embryonic brain sexual differentiation and breeding ability after sexual maturation. This study indicates that KAP3 gene may be useful as a gene marker to analyze the molecular mechanism of toxic response in the animal brain development and sexual maturation exposed to PCBs.

• 한국발생생물학회지:발생과생식
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• 제17권4호
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• pp.469-475
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• 2013

In mammals, puberty is a process of acquiring reproductive competence, triggering by activation of hypothalamic kisspeptin (KiSS)-gonadotropin releasing hormone (GnRH) neuronal circuit. During peripubertal period, not only the external genitalia but the internal reproductive organs have to be matured in response to the hormonal signals from hypothalamic-pituitary-gonadal (H-P-G) axis. In the present study, we evaluated the maturation of male rat accessory sex organs during the peripubertal period using tissue weight measurement, histological analysis and RT-PCR assay. Male rats were sacrificed at 25, 30, 35, 40, 45, 50, and 70 postnatal days (PND). The rat accessory sex organs exhibited differential growth patterns compared to those of non-reproductive organs. The growth rate of the accessory sex organs were much higher than the those of non-reproductive organs. Also, the growth spurts occurred differentially even among the accessory sex organs; the order of prepubertal organ growth spurts is testis = epididymis > seminal vesicle = prostate. Histological study revealed that the presence of sperms in seminiferous tubules and epididymal ducts at day 50, indicating the puberty onset. The number of duct and the volume of duct in epididymis and prostate were inversely correlated during the experimental period. Our RT-PCR revealed that the levels of hypothalamic GnRH transcript were increased significantly on PND 40, suggesting the activation of hypothalamic GnRH pulse-generator before puberty onset. Studies on the peripubertal male accessory sex organs will provide useful references on the growth regulation mechanism which is differentially regulated during the period in androgen-sensitive organs. The detailed references will render easier development of endocrine disruption assay.

• 한국발생생물학회지:발생과생식
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• 제14권1호
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• pp.35-41
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• 2010

Mammalian reproduction is regulated by a feedback circuit of the key reproductive hormones such as GnRH, gonadotropin and sex steroids on the hypothalamic-pituitary-gonadal axis. In particular, the onset of female puberty is triggered by gain of a pulsatile pattern and increment of GnRH secretion from hypothalamus. Previous studies including our own clearly demonstrated that genistein (GS), a phytoestrogenic isoflavone, altered the timing of puberty onset in female rats. However, the brain-specific actions of GS in female rats has not been explored yet. The present study was performed to examine the changes in the activities of GnRH neurons and their neural circuits by GS in female rats. Concerning the drug delivery route, intracerebroventricular (ICV) injection technique was employed to eliminate the unwanted actions on the extrabrain tissues which can be occurred if the testing drug is systemically administered. Adult female rats (PND 100, 210-230 g BW) were anaesthetized, treated with single dose of GS ($3.4{\mu}g$/animal), and sacrificed at 3 hrs post-injection. 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). ICV infusion of GS significantly raised the transcriptional activities of enhanced at puberty1 (EAP-1, p<0.05), glutamic acid decarboxylase (GAD67, p<0.01) which are known to modulate GnRH secretion in the hypothalamus. However, GS infusion could not change the mRNA level of nitric oxide synthase 2 (NOS-2). GS administration significantly increased the mRNA levels of KiSS-1 (p<0.001), GPR54 (p<0.001), and GnRH (p<0.01) in the hypothalami, but decreased the mRNA levels of LH-$\beta$ (p<0.01) and FSH-$\beta$ (p<0.05) in the pituitaries. Taken together, the present study indicated that the acute exposure to GS could directly activate the hypothalamic GnRH modulating system, suggesting the GS's disrupting effects such as the early onset of puberty in immature female rats might be derived from premature activation of key reproduction related genes in hypothalamus-pituitary neuroendocrine circuit.

• 정신신체의학
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• 제4권1호
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• pp.146-154
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• 1996

스트레스와 면역기능 간의 관계는 중추신경계, 신경내분비계 및 면역계 간의 의사소통 즉 상호작용에 의해 이루어지고 있다. 중추신경계와 면역계가 상호작용하는 주요 경로는 임파조직의 신경계 wiring system과 신경내분비계다. 면역계는 neuropeptide를 생성하고 이것은 면역반응을 조절한다. 정신사회적 인자와 면역기능 간의 중개자로는 뇌하수체에서 방출되는 peptide, hormone 및 자율신경계 물질이 있다. 시상하부는 내분비계, 신경계 및 면역계를 통합하는 역활을 한다. 특히 시상하부의 paraventricular nucleus가 이 일에 중추적인 역할을 담당한다. 한편 내분비계는 면역계에 의해서 휘이드백을 받는다. 뇌하수체가 면역계를 조절하는 주요 경로로는 시상하부-뇌하수체-부신-흉선축, 시상하부-뇌하수체-성선-흉선축, 송과선-시상하부-뇌하수체축 등이 시사되고 있다. 스트레스와 면역계 간에는 양 방향의 경로가 있는 것으로 가정된다. 즉 스트레스가 면역계에 영향을 미칠 뿐만 아니라 면역계가 정신사회적 기능에 영향을 미칠 수 있다. 따라서 스트레스와 면역기능 간의 관계를 규명하기 위해서는 면역계, 내분비계, 자율신경계 및 뇌활동을 동시에 측정, 비교하여 이들을 통합할 필요가 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제29권8호
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• pp.1065-1074
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• 2016

Growth factors play an important role during early ovarian development and folliculogenesis, since they regulate the migration of germ cells to the gonadal ridge. They also act on follicle recruitment, proliferation/atresia of granulosa cells and theca, steroidogenesis, oocyte maturation, ovulation and luteinization. Among the growth factors, the growth differentiation factor 9 (GDF9) and the bone morphogenetic protein 15 (BMP15), belong to the transforming growth factor beta (TGF-${\beta}$) superfamily, have been implicated as essential for follicular development. The GDF9 and BMP15 participate in the evolution of the primordial follicle to primary follicle and play an important role in the later stages of follicular development and maturation, increasing the steroidogenic acute regulatory protein expression, plasminogen activator and luteinizing hormone receptor (LHR). These factors are also involved in the interconnections between the oocyte and surrounding cumulus cells, where they regulate absorption of amino acids, glycolysis and biosynthesis of cholesterol cumulus cells. Even though the mode of action has not been fully established, in vitro observations indicate that the factors GDF9 and BMP15 stimulate the growth of ovarian follicles and proliferation of cumulus cells through the induction of mitosis in cells and granulosa and theca expression of genes linked to follicular maturation. Thus, seeking greater understanding of the action of these growth factors on the development of oocytes, the role of GDF9 and BMP15 in ovarian function is summarized in this brief review.

• 한국수산과학회지
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• 제44권6호
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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.

• Fisheries and Aquatic Sciences
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• 제17권1호
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• pp.115-121
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• 2014

Eyestalk ablation (ESA) is commonly used in aquaculture to stimulate ovarian maturation in crustaceans, and methyl farnesoate (MF) affects crustacean molting and reproduction. To investigate the physiological effects of ESA and MF treatments on the shrimp Litopenaeus vannamei, we compared the effects of single eyestalk removal and MF injections. The ESA group had the lowest survival rate (50%), and individuals in the $0.1{\mu}g$ and $1.0{\mu}g$ MF-treated groups had survival rates of 80 and 73.3%, respectively. Conversely, molting numbers were highest in the ESA group, and similar to those of the 1.0-${\mu}g$ MF group. To investigate shrimp growth, we measured body weight during the experimental period and found that individuals in the ESA and $1.0{\mu}g$ MF groups showed significant increases in body weight. Furthermore, to investigate the effects of ESA and MF treatments on gonadal maturation, the gonad somatic index (GSI) was calculated after the experiment. All treated groups (ESA and MF) had higher GSI values than the control group, but the ESA and $1.0{\mu}g$ MF groups were not significantly different. Using histological ovary analysis, we determined that all treated groups showed indications of the previtellogenic stage, unlike the control group (immature stage). These results suggest that the high-MF-concentration treatment produced effects similar to those of ESA with respect to molting number, growth, and ovarian maturation.

• Clinical and Experimental Reproductive Medicine
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• 제26권2호
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• pp.281-285
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• 1999

Kallmann's syndrome has both a general and specific connotation in describing general condition of gonadotropin-releasing hormone (GnRH) deficiency or a particular cluster of anomalies associated with primary eunuchoidism. The familial occurrence of hypogonadotropic hypogonadism associated with anosmia, color blindness, synkinesia, and mental defect is the classic Kallmann's syndrome. Interestingly, anosmia, or lack of smell, was not found in the absence of gonadal deficiency in the original study of this disorder. This disorder was found on both sexes, but the male to female ratio was 11:1, and Kallmann's syndrome is more often listed under disorders of male hypogonadism for this reason. Gross anatomy has shown disorders of the olfactory bulbs associated with Kallmann's syndrome and it was demonstrated a failure of GnRH-containing cells to migrate from the olfactory placode to the hypothalamus and preoptic area. We have experienced a case of Kallmann's syndrome which showed a hypoplasia of olfactory bulb in MRI during the workup of primary amenorrheic patient. So we report this case with a brief review of literatures.