• 한국수산과학회지
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• 제39권4호
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• pp.349-356
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• 2006

Gonad development in the sandfish Arctoscopus japonicus was investigated using a histological method. Specimens were collected monthly from April 2003 to March 2004, in the East Sea of Korea. The gonadosomatic index (GSI) of females began to increase in August, reached a maximum in November, and declined sharply in December. By contrast, in males, the GSI began to increase in June and reached a maximum in August. The annual reproductive cycle of A. japonicus can be divided into four successive stages in females: the early growing (January-March), late growing (April-August), ripe and spent (September-November), and recovery (December) stages. Males passed through early growing (January-April), late growing (May-July), ripe and spent (August-November), and recovery (November-December) stages. These results indicate that the spawning season was from October to December. The egg diameter of mature oocytes was 3.12$\pm$0.02 mm. The relationship between fecundity (F$_e$) and body length (BL) was F$_e$=0.4693BL$^{2.6825}$. Fecundity ranged from 483-2,254 eggs in a body length of 14.3-22.9 cm and increased with body length. The body length at 50% maturity was 14.80 cm, which corresponded to an age of 2.40 years.

• 한국수산과학회지
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• 제46권6호
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• pp.835-842
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• 2013

Flathead flounder Hippoglossoides dubius is a commercially important fish in the coastal waters of Gangwon Province, which is its spawning ground and breeding habitat. A total of 1,669 gonads were sampled monthly from February 2011 to May 2013 to investigate ecological characteristics, such as variations in maturation and spawning by gonad index, visual maturity stage, histological observations and oocyte diameter. Males were numerically dominant over females in the fishing grounds year round. The spawning season was from January to April, and the peak was from February to March. Oocyte number as a measure of fecundity was between 27,372 and 915,209 eggs with a length range of 26.0-48.7 cm TL, while the largest oocyte grew to 0.9-1.4mm in egg diameter during its spawning season. The relationship between fecundity and total length was $F=0.0016TL^{5.2539}$. The smallest mature lengths of the females and males were 28.4 and 22.6 cm respectively, and the 50% mature lengths of females and males were 32.9, 26.9 cm respectively.

• 한국어류학회지
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• 제7권1호
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• pp.33-42
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• 1995

1991년 8월부터 1993년 7월까지 경상남도 김해군 상동면 매리마을의 낙동강 지류에서 채집된 한국 특산어인 각시붕어, Rhodeus uyekii를 대상으로 생식생태를 파악하기 위하여 연간 생식소숙도지수(GSI)와 난경조성, 산란관 길이 변화를 조사하였고, 이들 생식소 발달과정을 광학현미경적 방법에 의해 조사하였다. GSI는 수온이 상승하기 시작하는 2월부터 증가하기 시작하여 5월에 연중 최대값을 나타내고, 7월부터 하강하여 8월에는 연중 최저값을 나타내었다. 이후 9월부터 11월까지 서서히 증가하다가 12월에는 일시적으로 증가를 멈추고 11월과 비슷한 수준을 유지하였다. 생식연주기는 7~8월의 퇴화 및 휴지기, 9~11월의 1차 성장기, 12월의 정체기, 1,2월의 2차 성장 및 성숙기, 3~6월의 완숙 및 산란기 등 연속적인 주기로 구분할 수 있었으며, 산란성기는 4월하순에서 5월이었다.

• 한국수산과학회지
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• 제45권3호
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• pp.246-252
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• 2012

The age and growth of the blackthroat seaperch Doederleinia berycoides was investigated based on samples captured in the southern seas of Korea from January to December, 2006. Age was estimated by analyzing otolith growth rings. The spawning period was extrapolated from August to November based on monthly changes in the gonad somatic index. The relationship between total length and otolith radius was analyzed separately for each sex with TL=-15.6174+10.3274R for females and TL=-4.4083+7.0749R for males. From the parameters calculated using average total length and weight when the year ring was formed, the growth of D. berycoides was expressed by von Bertalanffy growth equations as $L_t=34.71(1-e^{-0.2557(t+0.2078)})$, $W_t=713.85(1-e^{-0.2557(t+0.2078)})^{3.1972}$ for females, $L_t=27.37(1-e^{-0.3388(t+0.7362)})$, $W_t=353.91(1-e^{-0.3388(t+0.7362)})^{3.1647}$ for males, and $L_t=34.20(1-e^{-0.2530(t+0.2871)})$, $W_t=674.10(1-e^{-0.2530(t+0.2871)})^{3.1171}$ for pooled sexes, where L is total length at age t.

• 한국수산과학회지
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• 제33권3호
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• pp.184-191
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• 2000

포항 형산강 하구에 서식하는 참재첩, Corbicula leana을 대상으로 생식세포 형성과정 및 생식주기를 조직학적으로 조사하였다. 참재첩은 자웅이체로서 난생이며, 생식소는 완숙하면 암컷은 흑갈색, 수컷은 유백색을 띤다. 생식소관은 내장낭의 간중장선 하방으로 부터 근충의 외벽근층내에 있는 섬유성 망상결체조직까지 분포되어 있다. 난소는 수지상으로 연결된 난소소관으로 구성되어 있고, 정소 역시 많은 소관상의 정소소관으로 구성되어 있는데 이들 소관의 내강상피가 생식상피 기능을 하고 있다. 성숙난모세포는 배포의 변화로 알 수 있으며, 그 크기는 $70{\~}80{mu}m$ 정도이다. 난소 및 정소의 초기 발달에는 간충조직과 색소과립세포들이 영양세포로 관여하고 있으며 난소와 정소가 발달하면서 점차적으로 사라진다. 생식소 발달은 수온과 밀접한 연관성이 있고, 비만도의 변화도 주기성이 일치하였다. 생식주기는 분열증식기, 성장기, 성숙기, 방출기, 퇴화기 그리고 회복기 둥의 연속적인 주기로 구분할 수가 있다. 산란기는 6월 하순부터 9월 중순까지이고, 산란성기는 7월과 8월이었으며 생물학적 최소형은 10.0 mm 이상으로 조사되었다.

• 한국수산과학회지
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• 제33권3호
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• pp.219-224
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• 2000

난소의 내부는 결체성 조직인 다수의 난소박판으로 구성되며, 이곳에서 난원세포가 유래한다 정소조직상은 정세관 형태이며, 각각의 정세관은 여러 개의 소낭구조를 가진다. 각 소낭내의 생식 세포들은 같은 단계의 발달상태를 보인다. 군 성숙도에 도달하는 크기는 암${cdot}$수 모두 전장 4.5 cm이다. 암컷의 GSI는 6월에 가장 높은 값을 나타냈으며, 수컷의 GSI는 7월에 가장 높은 값을 나타냈다. 생식주기는 성장기 ($1{\~}3$월), 성숙기 ($4{\~}5$월), 완숙 및 산란기 ($6{\~}7$월) 그리고 회복 및 휴지기 ($8{\~}12$월)로 나눌 수 있었다. 난모세포 발달양식은 난군동기발달형에 속하며, 초기 성장기 난모세포의 세포질에서 난황핵이 관찰되었다.

• 한국발생생물학회지:발생과생식
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• 제20권4호
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• pp.305-314
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• 2016

The marine medaka, Oryzias dancena is a suitable sample as a laboratory animal because it has a small size and clearly distinguishes between female and male. Data on the growth and maturity of the diploid and triploid sea cucurbit species suitable for laboratory animals are very useful for studying other species. Triploidy was induced in the marine medaka by cold shock treatment ($0^{\circ}C$) of fertilized eggs for 45 min, applied two minutes after fertilization. The diploid and triploid male fish were larger than their female counterparts (P<0.05), and the concentrations of thyroid stimulating hormone (TSH) and thyroxine (T4) were higher in the induced triploids over 1 year (P<0.05). In both the diploid and tri-ploid groups the concentrations of TSH and T4 were higher in the male fish than in the females (P<0.05), while the testo-sterone and estradiol-$17{\beta}$ concentrations in the induced triploids were lower than in the diploids (P<0.05). The gonadosomatic index (GSI) of the triploid fish was lower than that for the diploids, and the GSI for females in each ploidy group were higher than that for the males. For both groups the GSI was highest at 4 months of age, and decreased thereafter to 12 months. Analysis of the gonads of one-year-old triploid fish suggested that the induction of triploidy probably causes sterility in this species; this effect was more apparent in females than in males.

• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2002년도 학술대회
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• pp.33-37
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• 2002

The present was performed to identify the effects of tributyltin (TBT) in the immature mice testes. 3-week-old male ICR mice were orally administrated on one time basis of TBT dose of O (Vehicle control, VC), 25 (TBT 25 mg/kg, T$_{25}$ ), 50 (TBT 50 mg/kg, T$_{50}$ ), 100 (TBT 100 mg/kg, T$_{100}$ ) mg/kg per each one. After 3 days the time treated of TBT, mice were sacrified and wighted body, testis, epididymis, seminal vesicle, vas deferens, and prostate. As the result of weighing, wights of each oragan and gonad index were tendency decresed in comparing groups of TBT treated with that (C) of unteated (p <0.05). As the result of examination of steroid hormones in the immature male mice, The concentrations of serum and intratesticular testosterone were significatly increased rather than the control group. But concentrations of estradiol were decresed objectly. A group of the highest change of concentrations of steroid hormones is T$_{100}$ . The high dose group, T$_{100}$ , was decreased all of concentrations of steroid hormones rather than those of T$^{25}$ . The result of observation with histological changes in testis showed a tendency for innercellular wall to increase damage and extinction in seminiferous tubles. As the result of investigation apoptotic cell numbers in the testis using teminal deoxy-nucleotidyl transferase -mediated dUTP-digoxygenin nick end-labeling immunohistochemical straia, The ratio of Apoptic cells significantly was incensed in depending on treatment of TBT does. In conclusion, these results shows that TBT triggers apoptosis on reproductive cell in testis and changes level of concentrations of steroid hormones in the immature male mice , as endocrine disruptors (EDs).

• 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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• 제21권3호
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• pp.305-314
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• 1994

19-norandrostenedione(19-NORA) is known as an intermediate in the metabolic pathway from androstenedione to estrone. Administration of esterified 19-nortestosterone, anabolic steroid, reduces serum gonadotropin and testosterone concentration, and results in reversible azoospermia in men. 19-NORA have been isolated from testis, but its function in testis is not clear yet. Therefore, this study was designed to determine the effect of 19-NORA on steroidogenesis and on spermatogenesis. 19-NORA was administrated by single intratesticular injection to adult male rats weighing 350-400 g in dose of 1 mg/50${\mu}l$. The serum and testis were collected on 1, 3, 7, 12, 48 hr after injection. The histological differences in testis were observed by routine paraffin method. The concentrations of testosterone and estradiol in serum and in left testis were determined by the conventional radioimmunoassays. One hour after 19-NORA treatment, serum concentrations of testosterone and estradiol increased significantly, compared to those of pre-treated(0 hr) group, and reduced gradually to the control level on 7 hour after injection. The concentration of testosterone in left testis increased slightly 1 hour after injection, and estradiol level increased significantly(p<0.05). Also, testosterone and estradiol level of control group revealed no difference with pre-treated (0 hr) group. Gonad index, structure of seminiferous tubules, and the number of step 7 th spermatid were simillar to control group. The present study suggests that the elevation of testosterone level results from increment of estradiol followed by the rapid metabolism of 19-NORA at 7 hour after injection, and then testosterone concentration may be recovered to control level by feedback mechanism of hypothalamus-hypothysis-testis axis.