• Journal of Aquaculture
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• v.21 no.4
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• pp.252-258
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• 2008

Gonadal development and reproductive cycle of the ark shell Scarpharca subcrenata were investigated by histological observations. Samples were collected monthly from March 2007 to February 2008 in the Yeoja Bay, Yeosu, Jeollanam-do, Korea. S. subcrenata was dioecious. The gonads consist of a number of oogenic follicle and acinus. Monthly changes in the gonad index reached a maximum in June and a minimum in September. Monthly changes in the condition index reached a maximum in April and a minimum in September. The reproductive cycle of this species can be divided into five successive stages: early active stage (January to April), late active stage (March to June), ripe stage (May to August), spent stage (July to September) and recovery and resting stage (September to March). The main spawning of S. subcrenata occurred in July and August in Yeoja Bay. The sex ratio of female to male was not significantly different from 1:1.

• Journal of Aquaculture
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• v.22 no.1
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• pp.34-41
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• 2009

Gonadal development and reproductive cycle of the granular ark Tegillarca granosa were investigated by histological observations. Samples were collected monthly from January to Decemberry 2002 in the Yeoja Bay of Yeosu, Jeollanam-do, Korea. T. granosa was dioecious. The gonads consist of a number of oogenic follicle and acinus. Monthly changes in the gonad index reached a maximum in June and a minimum in August. Monthly changes in the condition index reached a maximum in July and a minimum in September. The reproductive cycle of this species can be divided into five successive stages: early active stage (March to May), late active stage (April to June), ripe stage (May to July), spent stage (July to August) and recovery and resting stage (September to March). The spawning of T. granosa occurred in July and August in Yeoja Bay. The sex ratio of female to male was not significantly different from 1:1.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.5
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• pp.393-399
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• 2004

Annual reproductive cycle of Siganus canaliculatus was studied based on monthly variation of gonadosomatic index (GSI) and histological changes of gonads. Samples were monthly collected by a set net along the southern coast of Jeju Island, Korea from January to December, 1996. Variation of the monthly mean GSI values showed similar trends in female and male. The GSI values increased from June and reached a peak in the spawning season in July $(9.65{\pm}1.96\;in\;females,\;10.00{\pm}4.27\;in\;males)$, and decreased rapidly thereafter. Female hepatosomatic index (HSI) values ranged from $1.26{\pm}0.22\;(in\;April)\;to\;2.34{\pm}0.39$ (in July), and male HSI values ranged from $1.27{\pm}0.21\;(in\;April)\;to\;1.87{\pm}0.30$ (in October). Annual reproductive cycle was classified into the following successive stages: in female, growing stage (from February to June), mature stage (from June to July), ripe and spawning stage (from July to August), recovery stage (from August to March); and in male, growing stage (from January to June), mature stage (from June to July), ripe and spent stage (from July to August), and recovery stage (from August to April). Based on these data, this species has a group-synchronous oocyte development and one spawning season a year.

• Development and Reproduction
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• v.17 no.4
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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.

• Journal of Embryo Transfer
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• v.28 no.2
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• pp.149-155
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• 2013

Mullerian inhibiting substance (MIS) is a member of the TGF-${\beta}$ (transforming growth factor-${\beta}$) family whose members play key roles in development, suppression of tumour growth, and feedback control of the pituitary-gonadal hormone axis. MIS is expressed in a highly tissue-specific manner in which it is restricted to male Sertoli cells and female granulose cells. The serum levels of MIS in prenatal and postnatal ICR mice were measured using the enzyme-linked immuno-solvent assay (ELISA) using the MIS/AMH antibody. Mice were grouped by age: the significant periods were at the onset of development. During sex organ differentiation, no remarkable difference between female and male foetus MIS serum levels (both<0.1 ng/ml) was observed. However, MIS serum levels in pregnant mice markedly changed (4.5~12.2 ng/ml). After birth, postnatal female and male mice serum MIS levels changed considerably (male: <0.1~138.5 ng/ml, female: 5.3~103.4 ng/ml), and the changing phase were diametrically opposed (male: decreasing, female: fluctuating). These findings suggest that MIS may have strong associations with not only develop-ment but also puberty. For further studies, establishing the standard MIS serum levels is of importance. Our study provides the basic information for the study of MIS interactions with reproductive organ disability, cancer, and the effect of other hormone or menopause. We hypothesise that if MIS is regularly injected into middle-age women, meno-pause will be delayed. We detected that serum MIS concentration curves change with age. The changing phase is different between males and females, and this difference is significant after birth. Moreover, MIS mRNA is expressed during the developmental period (prenatal) and also in the postnatal period. This finding indicates that MIS may play a significant role in the developmental stage and in growth after birth.

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.105-111
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• 2013

The gonadal development of triploid and diploid Pacific abalones, Haliotis discus hannai was histologically investigated in spawning season. Diploid abalones had matured oocytes and spermatozoa, but most triploid had spermatocytes or developing oocytes that was slightly retarded in gonadal development compared to diploid abalones. In spawning experiment of triploid and diploid abalones, spawning rates of diploid male and female were 100%, but those of triploid female was 50% and male was 25% respectively. Investigation of spawned abalone eggs and spermatozoa revealed that length of diploid sperms head were 17.47 ${\mu}m$, breadth of head were 10.31 ${\mu}m$, length of spermatozoa were 130.72 ${\mu}m$, but those of triploid spermatozoa were 11.83 ${\mu}m$, 7.89 ${\mu}m$ and 103.36 ${\mu}m$ respectively. Triploid spermatozoa were significantly small to diploid spermatozoa (p < 0.05). The eggs of diploid and triploid were not different in size. The cross experiment between oocytes produced by triploids and spermatozoa by diploids ($3n{\times}2n$ cross) revealed that no fertilization were occurred, and $2n{\times}3n$ cross also revealed same result.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.5
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• pp.385-392
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• 2004

Gonadal development, gametogenesis, reproductive cycle, gonad index, and flesh weight rate of the murex shell (Ocenebra japonica) collected from the rocky intertidal zone of Buan-gun, Jeollabuk-do, Korea were investigated by means of histological method from January to December 2002. O. japonica had separate sexes, and was oviparous. The gonad was widely situated on the surface of the digestive gland located in the rear of the spiral flesh part in the shell. The male penis was located near the two tentacles. The ovary was composed of a number of oogenic follicles, and the testis was composed of several spermatogenic tubules. The size of ripe oocyte was approximately $140{\mu}m$ in diameter. The gonad index (GI) began to increase in March $(33.24{\pm}2.33)$ and reached the maximum in June $(47.77{\pm}1.90)$ Thereafter, the values decreased from July $(45.12{\pm}3.60)$ to October $(19.32{\pm}2.91)$. The flesh weight rate (FWR) began to increase in January $(25.93{\pm}1.32)$ and reached the maxium in May $(31.78{\pm}1.09)$ Thereafter, the values decreased from June $(31.50{\pm}0.66)$ to October $(24.09{\pm}1.60)$. The reproductive cycle could be classified into five successive stages: early active (October to April), late active (January to June), ripe (May to September), spawning (July to September) and recovery (September to February). The reproductive cycle was closely related to the seawater temperature.

• Development and Reproduction
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• v.4 no.2
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• pp.195-201
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• 2000

Sex differentiation process of the spotted sea bass, Lateolabrax maculatus, was investigated by histological method. The fish samples were collected from just after hatching to 365 days later. The primordial germ cells and genital ridge were appeared separately hanging under air bladder in 30-day larva (total length: 11.7~13.2 mm), and were unified into the undifferentiated gonads in 40-day larva (12.5~14.0 mm). The ovarian differentiation was started in 60-day juvenile (23.6~27.0 mm). The somatic tissues were elongated in tip of both ends of undifferentiated gonad and were fused each other. The complete ovarian cavity was appeared in 80-days juvenile(33.1~42.5 mm). The testicular differentiation was initiated in 70-day juvenile (24.8~31.6 mm). The rudiment of sperm duct was appeared in the center of the undifferentiated gonad. The meiosis of germ cells in the ovary was started in 168-day juvenile (88.0~115.4 mm). In 287-day juvenile (175.1~233.6 mm), the ovary was filled with both of chromatin stage and perinucleolus stage oocytes. The meiosis of male germ cells was started in 245-day juvenile (124.4~168.3 mm). However, the seminiferous tubules of testis were filled with numerous sperm in 365-day juvenile (162.5~253.8 mm). The sex ratio of male and female was 1:1.38. Considering these results, the spotted sea bass was showed differentiated type in sex differentiation and gonochorism in sexuality.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.6
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• pp.854-861
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• 2012

To investigate the role of water temperatures and photoperidos as environmental cues regulating reproductive rhythm in banded catfish Pseudobagrus fulvidraco, rearing experiments were conducted using sveral rearing regimes conbined with changes in photoperiods and water temperatures during growing and spawning periods. GSI of $23^{\circ}C$ was significantly higher than $18^{\circ}C$ in female, but 9 light of 18 and $23^{\circ}C$ were no difference in male. In case of estradiol, $18^{\circ}C$ and 15 L was higher than other experintal precinct after 20 days. But, end of the experiment, all of experimental precinct were no difference. Testosteron of female was no difference in $18^{\circ}C$-9 and 15 L after 20 days. Testosteron of male was no difference in $18^{\circ}C$-9 L. In case of 11-KT, control level was $0.39{\pm}0.03$ ng/mL and $18^{\circ}C$-9 L was no significantly difference after 20 days. But, 15 L was higher than other experimental precinct.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.6
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• pp.1003-1012
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• 2012

The gonadosomatic index (GSI), sex steroid hormones and gonadal development of roughscale sole Clidoderma asperrimum cultured in indoor tank were investigated to evaluate its sexual maturation and reproductive cycle. The highest GSI values of female and male were $6.91{\pm}4.03$ (May) and $0.16{\pm}0.08$ (August), respectively. The reproductive cycle would be classified into four successive developmental stages: growing stage (December to February), maturation stage (March to April), ripe and spawning stage (May to June), recovery and resting stage (July to November). The highest plasma testosterone (T) and estradiol-$17{\beta}$ ($E_2$) levels of female were $259.4{\pm}76.8$ and $633.3{\pm}182.5$ pg/mL, respectively in May. Also $17{\alpha}$, $20{\beta}$-dihydroxy-4-pregen-3-one ($17{\alpha}$, $20{\beta}$-OHP) levels of female peaked in April before spawning season ($244.2{\pm}42.5$ pg/mL). The highest plasma testosterone (T) and 11-ketotestosterone levels of male were $231.0{\pm}46.0$ and $273.9{\pm}54.5$ pg/mL, respectively in April. But there was no significant difference in $17{\alpha}$, $20{\beta}$-OHP.