• Ocean and Polar Research
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• 제38권1호
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• pp.81-88
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• 2016

In many fish species, including Nile tilapia (Oreochromis niloticus), gonadal development occurs at the expense of stored energy and nutrients. Therefore, reproductive systems are inhibited by limited food supply. It has been well established that reproductive function is highly sensitive to both metabolic status and energy balance. Nothing is known about the possible mediated connection between energy balance and reproduction. Kisspeptin, a neuropeptide product of the Kiss gene has emerged as an essential gatekeeper of reproduction and may be possibly be linked to energy balance and reproduction in non-mammalians. Thus, in this study, the effect of fasting (10 days) on the expression of kisspeptin and the gonadotropin-releasing hormone (GnRH) gene were assessed in Nile tilapia (male and female) using qRT-PCR. In addition, plasma levels of estradiol-$17{\beta}$ ($E_2$) and 11-ketotestosterone (11-KT) in adult tilapia were measured by ELISA. In male tilapia, fasting reduced Kiss2 and GnRH I mRNA expression in the brain and 11-KT level in comparison with the fed tilapia (p < 0.05). In females, however, there were no significant differences in GnRH I mRNA expression and $E_2$ between fish subjected to fasting and those fed (p > 0.05). These data indicate the impact of nutritional states on kisspeptin as a potential regulatory mechanism for the control of reproduction in male Nile tilapia.

• Clinical and Experimental Reproductive Medicine
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• 제21권3호
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• pp.297-303
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• 1994

The effect of radiation on the steroidogenesis of rat ovary was investigated. For this purpose, female rats aged 7-8 weeks were exposed to a single dose of ${\gamma}$ radiation(320 rad or 800 rad) by the cobalt-60. At fourth(day of the first estrus) and eighth(day of the second estrus) days after irradiation, the concentrations of serum steroid hormones were determined by radioimmunoassays (RIA). The correlation between survival rate(Y) and radiation dose(X) was Y=-0.06X+100(r=0.89, n=10). Lethal dose$(LD)_{50(30)}$ and $LD_{20(30)}$ were 833.33rad and 333.33rad respectively. The weights of body and ovary was decreased significantly by the $LD_{50(30)}$ irradiation during the 4 days, but both weights were recovered at day 8. The serum levels of 17a-hydroxyprogesterone(170HP) and estradiol($E_2$) in the irradiated rats were not generally different from those of control. However, the levels of testosterone(T) and 19-norterstosterone(19NT) in the irradiated rat at $LD_{50(30)}$ and $LD_{20(30)}$ radiation doses were decreased, while progesterone levels in serum of the irradiated rats were slightly increased. These results suggest that irradiation may inhibit the first step of steroidogenesis, especially the conversion of P to T, in the rat ovary.

• Clinical and Experimental Reproductive Medicine
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• 제32권3호
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• pp.199-206
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• 2005

연구목적: 난포가 폐쇄되는 동안의 생화학적 변화를 규명하기 위하여 미성숙 돼지의 정상 및 폐쇄 난포 내 lactate dehydrogenase (LDH) 활성도 변화 및 동일 난포액 내 스테로이드호르몬의 농도변화를 알아보기 위하여 본 연구를 시행하였다. 재료 및 방법: 난포액 (FF), 과립세포 (GC), 협막세포 (TC) 내 LDH의 활성도를 측정하였으며, 난포액 내 progesterone ($P_4$), testosterone (T), estradiol ($E_2$)의 농도변화를 방사면역측정법으로 정량하였다. 결　과: 정상 및 폐쇄 난포에서 $P_4$의 농도변화를 보이지 않았다. 그러나 폐쇄 난포액 내 T의 농도($3.85{\pm}1.50ng/ml$)는 정상 난포 ($1.29{\pm}0.54ng/ml$)에 비해 현저히 높았으며 정상 난포 내 $E_2$의 농도 ($43.29{\pm}19.51ng/ml$) 는 폐쇄 난포 ($18.82{\pm}7.27ng/ml$)에 비해 현저히 높은 것으로 나타났다. 정상 난포액 내 $P_4$의 농도는 난포의 크기에 정의 상관관계 (r=0.75)를 보였다. 정상 난포 내 T:$P_4$의 비율 ($8.14{\pm}3.35$)은 폐쇄 난포 ($1.39{\pm}0.60$)에 비해 현저히 높았으며, 정상 TC ($433.63{\pm}102.40{\mu}U/{\mu}g$ DNA) 및 FF ($246.86{\pm}58.96{\mu}U/{\mu}l$) 내 LDH 활성도는 폐쇄 난포 (각각 $83.7{\pm}10.5$와 $38.71{\pm}9.00$)에 비해 현저히 높게 나타났다. 정상 난포의 GC 및 FF 내 LDH 활성도는 $E_2$의 농도와 부의 상관관계를 보였지만, 폐쇄 난포의 TC 내 LDH 활성도는 $P_4$, T, $E_2$의 농도에 대해 정의 상관관계를 나타내었다. 결　론: 본 실험의 결과, 미성숙 돼지 난포의 폐쇄는 TC 내 LDH 활성도 감소와 밀접한 관계를 갖는 것으로 사료된다.

• 한국양식학회지
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• 제19권4호
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• pp.267-274
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• 2006

자연산(silver 및 yellow) 뱀장어의 인위적인 성성숙 과정중에 체중 및 혈중 성호르몬 농도를 조사하기 위해 연어 뇌하수체 추출물(SPE; 20 mg pituitary powder/fish)를 Freund's incomplete adjuvant로 water-in oil (W/O) 형태로 유화시켜 매주 복강에 주사하였다. Eel's Ringer액만으로 유화시켜 주사한 대조구(silver 및 yellow) 뱀장어의 경우, 체중은 서서히 감소하는 경향을 나타내었으며, 혈중 성호르몬(testosterone; T, $estradiol-17{\beta};\;E_2$ 및 $17{\alpha},20{\beta}-dihydroxyprogesterone$; DHP)의 농도도 실험기간 동안 거의 변화없이 서서히 감소하는 경향을 나타냈었지만 유의적인 변화는 없었다. 한편, 매주 SPE로 주사한 silver 뱀장어는 투여 6주후부터 급격한 체중변화가 일어났으며, 대부분 개체의 난모세포는 핵이동기로 구성되어져 있었다. 또한 혈중 T와 $E_2$ 농도의 두드러진 증가는 투여 6주후부터 관찰되어 졌다. 매주 SPE로 주사한 yellow 뱀장어의 경우, 대부분 개체는 투여 5주까지 체중 변화가 완만하게 나타났으며 그 이후 급속히 증가하였다. 이들 개체의 대부분은 실험종료시에도 제3 난황구기의 난모세포들로 구성되어져 있었다. 특히 실험 기간중 혈중 T와 $E_2$ 농도는 개체별로 다양하게 나타났으며, 유의한 차이는 제각기 투여 8주째와 투여 6주 후 부터 두드러지게 증가하였다. 그러나 매주 SPE로 주사한 자연산 뱀장어(silver 및 yellow)의 혈중 DHP 농도는 실험 기간동안 불검출 혹은 매우 낮은 농도로 유지하였으며, 유의적인 변화는 관찰되지 않았다. 본 연구의 결과, sliver 뱀장어에 있어서 SPE를 W/O 형태로 유화시켜 반복 투여함으로써 체중 및 혈중 성호르몬(T와 $E_2$)의 급격한 증가 및 최종성숙을 유도하는데 효과적이었다.

• 동의생리병리학회지
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• 제16권1호
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• pp.124-132
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• 2002

Daebangpung-tang(DBPT) is one of the prescriptions used for the treatment of rheumatoid arthritis(RA) in oriental medicine. The present study aimed to examine the analgesic effect of DBPT on a rat model of CFA-induced arthritis, which is not identical to human auto-immune arthritis although it does have many features in common with RA, and the relation between DBPT-induced analgesia and steroid hormones. CFA-induced arthritis rat model used to test the effect of DBPT was chronic pain model. After the induction of arthritis, rats subsequently showed a reduced stepping force of the affected limb for at least the next 18 days. The reduced stepping force of the limb was presumably due to a painful knee, since oral injection of indomethacin produced temporary improvement of weight bearing. DBPT dissolved in water was orally administrated. After the treatment, behavioral tests measuring stepping force were periodically conducted during the next 4 hours. DBPT produce significant improvement of stepping force of the hindlimb affected by the arthritis lasting at least 3 hours. The magnitude of this improvement was equivalent to that obtained after an oral injection of 3mg/kg of indomethacin and this improvement of stepping force was interpreted as an analgesic effect. The reduced stepping force was divided into three stages(10-30g, 30-50g, and 50-70g). All experiments was performed at 50-70g of stepping force, since both DBPT and indomethacin showed the most excellent analgesic effect at 50-70g of stepping force. DBPT produced the improvement of stepping force of the affected hindlimb in a dose-dependent manner and showed analgesic effect on neuropathic pain as well. DBPT-induced analgesic effect could not be blocked by systemic injection of steroid antagonist mifepristone. The present study suggest 1) that DBPT produces a potent analgesic effect on the chronic knee arthritis pain model in the rat and 2) that steroids system does not mediate DBPT-induced analgesia.

• 한국어류학회지
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• 제12권1호
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• pp.71-84
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• 2000

1997년 7월부터 1999년 6월까지 2년간 제주도 남부해역인 중문 하예동 연안에서 매월 채집한 말쥐치, Thamnaconus modestus의 생식주기를 조직학적인 방법으로 연구하였다. 암 수컷의 GSI 변화에 있어서 암컷은 5월, 수컷은 6월에 년 중 최고값을 보였다. 생식주기는 암컷인 경우 성장기 3~4월, 성숙기 4~5월, 산란기 5~6월, 퇴화 및 휴지기 7~2월로 구분되었고, 수컷인 경우 성장기 1~3월, 성숙기 4~5월, 방정기 5~6월, 퇴화 벚 휴지기 7~12월로 구분할 수 있었다. 산란기간 동안 말쥐치 암컷을 대상으로 이들의 산란주기 및 산란횟수를 알아보기 위해 생식소 발달상을 조직학적인 방법으로 관찰하고 성 steroid 호르몬인 estradiol-$17{\beta}$ ($E_2$)와 testosterone (T)의 혈중 농도를 RIA 검사를 통하여 조사한 결과 말쥐치는 비동시발달형에 속하는 어종으로 산란기간내 적어도 2 회 이상 산란을 하는 다회산란종으로 추정되며, $E_2$와 T의 혈중 농도 변화는 난모세포의 성숙과 GSI 변동에 거의 상동적으로 변화하고 있었다.

• 한국수산과학회지
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• 제38권5호
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• pp.309-315
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• 2005

Changes of sex steroid hormones in the plasma of yellowfin goby, Acanthogobius flavimanus were investigated in relation to the gonadosomatic index (GSI), the hepatosomatic index (HSI) and gonadal development. The GSI in females rose rapidly in November and remained high from December to May $(7.26\pm0.89­6.62\pm0.02)$. The Male's GSI also increased gradually from November and was highest in May $(0.16\pm0.08)$. The HSI in both sexes was in reverse correlation with the GSI, and the HSI was low during the spawning season (February-May). In females, the $estradiol-17{\beta}\;(E_2)$ level increased during vitellogenesis (November and December) and reached its maximum $(8.13\pm2.87 ng/mL)$ at the maturing period, in January. $17{\alpha},\;20{\beta}$-dihydroxy-4-pregnen-3-one$(17{\alpha}20{\beta}OHP)$ gradually increased from October $(0.063{\pm}0.02ng/mL)$ to March $(0.16{\pm}0.02ng/mL)$ and increased rapidly in May. The level of testosterone (T) showed a similar tendency of $E_2$. In males, T increased gradually during spermatogenesis from September to December $(0.14{\pm}0.06­0.26{\pm}0.10ng/mL)$ and peaked in January $(0.36{\pm}0.29 ng/mL)$ when the spermatozoa filled the testis. 11-KT also rose markedly in January and then decreased. On the other hand, $17{\alpha}29{\beta}OHP$ in males did not show any clear tendencies.

• Reproductive and Developmental Biology
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• 제41권1호
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• pp.1-6
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• 2017

In all mammalian species, progesterone is essential to both the preparation for, and maintenance of, pregnancy. The $20{\alpha}$-hydroxysteroid dehydrogenase ($20{\alpha}$-HSD) enzyme predominantly converts progesterone into its biologically inactive form $20{\alpha}$-hydroxyprogesterone, thereby regulating its activity. Thus, to directly assess sexual maturation in the MediKinetics $micropig^{(R)}$, we analyzed the concentration of the steroid hormones progesterone and estradiol during the estrous cycle. Our results show that the progesterone level exhibited by the analyzed $micorpig^{(R)}$ was low at the beginning of the estrous cycle, and then abruptly increased to $30.32{\pm}10.0ng/mL$ and $46.37{\pm}11.0ng/mL$ by days 9 and 11 of the cycle, respectively. It reached the highest level $55.87{\pm}3.5ng/mL$ on day 13 of the estrous cycle, before decreasing to $46.58{\pm}13.1ng/mL$ and $10.0{\pm}7.6ng/mL$ by days 15 and 17 of the cycle, respectively. In contrast, the estradiol level was shown to be highest ($27.13{\pm}11.2ng/mL$) at the initiation of the estrous cycle, after which point it decreased to $13.29{\pm}6.5ng/mL$ and $10.94{\pm}5.9ng/mL$ by days 4 and 5 of the estrous cycle, respectively. By day 17 of the estrous cycle, the estradiol level decreased to $4.13{\pm}7.6ng/mL$. We anticipate that these results will provide useful information to enable the study of human ovulation and reproductive physiology using the MediKinetics $micoripig^{(R)}$ as a model system. We recommend further investigation to elucidate the functional mechanisms underlying the regulation of sexual maturation in the MediKinetics $micropig^{(R)}$.

• 한국발생생물학회지:발생과생식
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• 제16권1호
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• pp.39-45
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• 2012

To verify the sex steroids which are involved in oocyte maturation of the blacktip grouper, $Epinephelus$ $fasciatus$, we incubated vitellogenic oocytes (0.41 and 0.50 mm in average diameter) in the presence of exogenous steroid precursor ($[^3H]17{\alpha}$-hydroxyprogesterone). Steroids were extracted, separated and identified by thin layer chromatography. The major metabolites produced were androstenedione, estradiol-$17{\beta}$, estrone and progestogens. Progestogen metabolites in the oocytes of 0.50 mm were more abundant than those of 0.41 mm. Also, we investigated the $in$ $vitro$ effects of human chorionic gonadotropin (HCG; 5, 50 and 500 $IU/m{\ell}$), $17{\alpha},20{\beta}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}P$) and $17{\alpha},20{\beta}$-trihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}21P$; 5, 50 and 500 $ng/m{\ell}$, respectively) on oocyte maturation. In the oocytes of 0.41 mm, treatment with 50 IU HCG stimulated GVBD ($55.30{\pm}1.20%$) compared with controls ($32.41{\pm}3.13%$, $p$<0.05). In the oocytes of 0.50 mm, treatment of $17{\alpha}20{\beta}P$ (50 and 500 $ng/m{\ell}$) stimulated GVBD ($50.13{\pm}2.52$ and $51.77{\pm}5.91%$, respectively) compared with controls ($36.81{\pm}2.89%$, $p$<0.05). Treatment with 500 IU HCG also stimulated GVBD ($49.59{\pm}5.15%$) compared with controls ($p$<0.05). Taken together, these results suggested that both HCG and $17{\alpha}20{\beta}P$ were effective on in vitro oocyte maturation and $17{\alpha}20{\beta}P$ may act as a maturation inducing hormone in blacktip grouper.

• Asian-Australasian Journal of Animal Sciences
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• 제27권4호
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• pp.479-487
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• 2014

Leptin plays an important role in energy homeostasis and reproductive function in fish, especially in reproduction. Migrating fish, such as salmonoids, are affected by external environmental factors, and salinity changes are a particularly important influence on spawning migrations. The aim of this study was to test whether changes in salinity affect the expression of leptin, estrogen receptors (ERs), and vitellogenin (VTG) in chum salmon (Oncorhynchus keta). The expression and activity of leptin, the expression of ERs and VTG, and the levels of estradiol-$17{\beta}$ and cortisol increased after the fish were transferred to FW, demonstrating that changes in salinity stimulate the HPG axis in migrating female chum salmon. These findings reveal details about the role of elevated leptin levels and sex steroid hormones in stimulating sexual maturation and reproduction in response to salinity changes in chum salmon.