• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.327-339
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• 1991

The present paper is a histological study of neurosecretory cells in the brain and the thoracic ganglion with the gonadal development in Palaemon serrifer. The reproductive cycle includes the successive stages of the growing period (February-March), the mature period(April-May), the ripe and spent periods(June-August) and the degenerative and resting periods(September-January). The neurosecretory cells are grouped into four types based on Matsumoto(1958) : A-,A'-, B- and E-cells. A- and A'-cells are $80-90{\mu}m,\;B-cell\;is\;30-40{\mu}m$ and E-cell is $10-15{\mu}m$. A- and B-cells are the positive to CHP and AF, while B-cell is the positive only to AF. The secretory grannules of a A-cell are transported to the axon, and at the same time they are discharged through the peripheral membrane. Of the four neurosecretory cells, A- and I-cells show the difference of secretory activity according to the gonad developmental process. In the female, A-cells show secretory activity for the ripe and spent periods, while I-cells show for the mature, ripe and spent periods. In the male, A-cells show secretory activity for the mature, ripe and spent periods, while I-cells show for the growing, mature, ripe and spent periods.

• Korean Journal of Ichthyology
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• v.23 no.3
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• pp.179-186
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• 2011

Slime flounder, Microstomus achne is distributed in the coastal waters of Korea, west sea of Japan, BoHai, Yellow sea and East china sea. They are mainly caught by bottom trawl net during winter, from December to March. Sexual maturation of slime flounder were investigated using samples collected from commercial catch in the southern coast of Korea from November, 2006 to March, 2007. The ovary of the slime flounder is a conical bag in shape and is bilateral structure develops lengthily from the posterior of the abdomen to the end of the anal fin. The testis also is bilateral in structure, usually located in small size in the abdomen. In females, the gonadosomatic index (GSI) were peaked in January (12.46), then decreased rapidly thereafter. Female GSI values plummeted to 2.72 in March just after spawning. Male GSI values were peaked in December (2.46) before in the spawning season, then decreased slowly thereafter. The reproductive cycle would be classified into three successive developmental stages : maturation stage (November to January), ripe and spawning stage (December to February), degenerative and resting stage (February to March). Relationships between the fish sizes in total length (TL) and the number of ovarian eggs (F), the body weights (BW) and the number of ovarian eggs were indicated by the exponential equation respectively: F=29.027TL-767.8 (r$^2$=0.7686), F=0.3998BW+24.288 (r$^2$=0.8919).

• Korean Journal of Ichthyology
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• v.10 no.2
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• pp.191-199
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• 1998

The ovary of the spotted flounder Verasper variegatus is a conical bag in shape and is bilateral structure develops lengthily from the posterior of the abdomen to the end of the anal fin. The testis also is bilateral in structure, usually located in small size in the abdomen. In females, the gonadosomatic index (GSI) showed very low from March to July, and then began to increase from August, thereafter reached the maximum in January through out the year. In males, the GSI reached the maximum (1.7) in January through out the year, as seen in females. Compared with the male GSI in other fishes, the maximum GSI of this species were very lower than those of other fishes. According to the distributions of egg diameter in the spawning season, it is assumed that the spotted flounder spawn four times or more in the spawning season. The total length of female and male reached 50% first sexual maturity were 42.0~44.0 and 28.0~30.0cm, respectively and total length of female and male reached 100% maturity were 44.0 and 32.0cm, respectively. The reproductive cycle could be classified into four successive developmental stages: growing stage (August~October), mature stage (November~December), ripe and spent stage (December~February), degenerative and resting stage (March~July).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.3
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• pp.206-218
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• 1984

The gonadal development and gametogenesis of shad, Konosirus, punctatus (TEMMINCK et SCHLEGEL) were studied by comparing with various quantitative indices, such as seasonal changes of gonadosomatic index, fatness, egg-diameter composition, first maturing size, and by comparing with histological changes of gonad and gonadotrophs(GTH) in pituitary. The materials were monthly sampled from Dadaepo at the estuary of the Nakdong river in Korea from September, 1982 to October, 1983. The ovary of shad is a pair of sac-shaped organs revered with a fibromuscular capsule and consisting of numerous sacs. The type of testicular structure is lobular type with development of germ cells, mesenchymal tissue on the lobuli. The gonadosomatic index (GSI) is rather low till March, but increases in April and reaches to peak in June in females and May in males. And it suddenly falls in July. The gonads become active on the increase of water temperature and spawning season ends before high water temperature. After spawning, the small oocytes continue to remain as they are untill the growing period next year. The reproductive cycle includes the successive stages of growing from March to April, mature from April to May, ripe and spawning in June, and recovery and resting from July to February next year. In egg-diameter composition of an ovary taken in the spawning season, 2-3 modes were recognized with some batches shown in an ovary. An individual shad spawns twice or more in a month-spawning season. The individual spawning interval is estimated to be ten days or less. Changes of fatness are corelated with those of water temperature that affect on the condition of feeding, but less corelated with spawning. The percentage of mature of female and male fish, are $50\%$ in 17.0-18.0 cm and $100\%$ in 18.0-19.0 cm. GTH cells are activated from growing period and decrease their activity at pre-spawning season with peak activity for mature period.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.31-37
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• 2000

This study was designed to identify the ultrastructural changes of mouse endometrium during peri-implantation period and obtain the fundamental information for the establishment of 3-dimensional culture system of mouse endometrial cells in vitro. The used female ICR mice ($6{\sim}8$ wks) were conducted on pregnant. The biopsies were obtained from whole uterus at cycle day 1 (D1) and day 5 (D5) after hCG injection and mating. The biopsies materials were fixed 2.5% glutaraldehyde and 1% osmium tetroxide. Subsequently, for observation using light and transmission electron microscopy (LM and TEM), they were dehydrated and embedded in Epon and the embedded biopsies were sectioned and stained. For scanning electron microscopy (SEM), the fixed specimens were dehydrated, dried and coated with gold. 1) For LM, the biopsied materials at D5 (late secretory phase) were appeared the extended stromal layer by increased connective tissues and the fully developed endometrial glands and vessels compared with D1 (early secretory phase). 2) For TEM, the mouse endometrium was consisted of 3-layers, a simple polarized columnar epithelial cells, basement membrane and stromal cells. At D5, the distribution of microvilli, endoplasmic reticulum, Golgi body, lipid and glycogen deposits, secretory granules and surface area of basement membrane were increased. 3) For SEM, the degree of folding and microvilli of surface of mouse epithelial cells was became more and more according to the process of secretory phase, and at D5, implantation time of mouse, the appearance of pinopodes as a specific marker of uterine receptivity was found. The uterine pinopodes of mouse were found in narrow sites at the luminal surface, irregularity and appeared the different stages in the same sample. Therefore, these results indicated that the mouse endometrium was experienced dramatic morphological changes during peri-implantation period.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.5
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• pp.266-280
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• 1989

Gonadal maturation of the Korean pomfrets, Pampus echinogaster (Basilewsky) and Pampus argenteus (Euphrasen) were histologically investigated based on the samples captured in the East China Sea from January 1987 to December 1988. Gonadosomatic index (GSI) of P. echinogaster began to increase from March, and reached maximum between May and July. It began to decrease from July and reached mini-mum between August and February. P. argenteus had a similar cycle, however, P. argenteus has higher values in April than P. echinogaster. Hepatosomatic index (HSI) were positively related to GSI. HIS of P. echinogaster and P. argenteus reached maximum in $April\~July$ and $April\~August$, respectively, Fatness coefficient of two Pampus species were low in the summer, and high in the winter. Ovary is of saccular structure, and testis is of lobular structure. From February, the early oocyte (ca. $100\mu$ in diameter grows) rapidly at the germinal epithelium of ovarian sacs. From March to April the oocytes grew up to cu $400\~500\mu$ in diameter. At this stage, the yolk globules are accumulated rapidly in the cytoplasmic layer. From May, the oocytes roached ca. $650\~850\mu$ in diameter, and they are spawned in $May\~July$. After spawning the residual follicles and remained ripe eggs degenerate. From February, spermatogonia grows into spermatocyte on the epithelium of the testicular lobuli. From May, spermatozoa appeared and spawning occurs. After spawning, the epithelium is thickened and the remained spermatozoa degenerate. Annual reproductive cycle of two Pampus species could be divided into four successive stages: Growing stage ($March\~April$), Mature stage ($April\~May$), Ripe and spent stage ($June\~July$) and Recovery and resting stage ($August\~January$). Absolute fecundity of P. echinogaster was $9,441\~135,294$, and that of P. argenteus was $50,678\~221,894$. Absolute fecundity of two Pampus species were positively related to body length and total weight. Relative fecundity was positively related to body length, while it was reversely related to total weight. The increasing rate of absolute fecundity of P. echinogaster was lower than P. argenteus. In P. echinogaster half of female and male reached first maturity at body length of $15.0\~$17.9cm and $12.0\~14.9cm$, respectively. All of females and males reached first maturity at body length of $18.0\~20.9cm$ and $21.0\~23.9cm, respectively. In P. argenteus all of females and males reached first maturity at body length of 18.6cm and 16.7cm$, respectively.