• The Korean Journal of Malacology
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• v.25 no.2
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• pp.173-178
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• 2009

The bigfin reef squid, Sepioteuthis lessoniana is commercially important species in Korea. Korean fishing vessels have actively caught it. However, the reproductive Biology of this species has been poorly known. Therefore, the purpose of this study is to provide information on the reproductive biology of Sepioteuthis lessoniana in Jeju Island, Korea. The bigfin reef squid caught by set net, from June to November 2006. Monthly changes in maturity stages, gonad weight, mantle length at 50% group maturity and sex ratio were investigated. The mantle length of the bigfin reef squid was between 10.6 and 32.1 cm. Maturation and spawning occur all year around, with more intensity from July to September, with peak July. The spawning period was June. The mantle length at 50% group maturity was estimated to be 18.01 cm. Sex ratio was 1:1.4 (male:female). The proportion of female was significantly higher than male ($x^2$-test, p > 0.01).

• Korean Journal of Ichthyology
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• v.23 no.4
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• pp.261-268
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• 2011

To clarify the annual reproductive cycle of the Korean perch, Coreoperca herzi, the seasonal changes in gonadosomatic index (GSI), hepatosomatic index (HSI), histological aspects of gonad and liver, and plasma levels of sex steroid hormones were investigated from June 1994 to April 1996. The annual variations of GSI and HSI were positively related to the plasma levels of sex steroid hormones. Estradiol-$17{\beta}$ (E2) and testosterone levels were raised during the April to May. Based on the related results, annual reproductive cycle of the fish could be divided into five successive stages; 1) Growing stage (from February to March: GSI was increased rapidly and oocytes with yolk vesicle was increased. Nucleus migrates toward the animal pole. Spermatids were activated from the epithelial tissue of lobuli). 2) Maturation and spawning stage (from April to June: Oocytes were accumulated yolk globules. Active spermatogenesis was observed). 3) Degeneration or stagnation phase (from July to August). 4) Recovery phase (from September to November) and 5) resting phase (from December to January). The main spawning period was in May.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.287-296
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• 2014

Chicken eggs undergo various physiological changes during egg maturation. To study genes associated with the egg maturation in pre-ovulation (immature) and post-ovulation (mature), we compared gene expression patterns between in the immature egg and mature egg using RNA sequencing data. Mature and immature eggs were obtained from a Heuksaek Jaerae-jong of Korean native chicken. Total RNAs obtained from the eggs were sequenced by Illumina HiSeq 2000 platform, and the generated sequence reads were mapped to Galgal4 reference sequence assembly using Tuxedo Protocol. From the comparison of the RNA sequencing data, 315 genes were differentially expressed between mature and immature eggs, and 46 genes were only detected in immature egg. Further gene ontology (GO) analysis was performed for the differentially expressed genes using DAVID, showing that 29 and 28 GO terms were independently clustered from mature and immature, respectively. From those clustered GO terms, genes related to germ cell development, sex differentiation and defense response to bacterium were mainly expressed in the immature egg, while genes related to regulation of apoptosis, steroid metabolic process and lipid homeostasis were mainly detected in the mature egg. Our results could contribute to understand egg maturation before and after ovulation, and develop genetic markers for improving egg quality and productivity.

• Development and Reproduction
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• v.17 no.3
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• pp.241-246
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• 2013

To effects of sex maturation in olive flounder by regulating long photoperiod, gonadal development and GTH mRNA expression in the pituitary were investigated. Photoperiod was treated natural photoperiod and long photoperiod (15L:9D) conditions from September 2011 to March 2012. The results showed that natural photoperiodic group showed a higher gonadosomatic index (GSI) than long photoperiodic group during the spawning season (March 2012). The histological analysis of ovarian tissue showed that natural photoperiod group of ovaries contained vitellogenic oocytes, but long photoperiod group of ovaries mainly contained perinucleolus staged oocyte and oil-drop staged oocytes. The FSH mRNA of olive flounder, under natural photoperiod group, showed a significantly higher expression but no significant difference under long photoperiod group. The $LH{\beta}$ mRNA showed a significantly higher expression only under natural photoperiod group. These results may suggest that long photoperiodic information regulates secretion of pituitary FSH and LH and maintain early growing stage of gonadal development in this species.

• Development and Reproduction
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• v.21 no.3
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• pp.275-286
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• 2017

The purpose of this study is to investigate the differences fatty acids and hormonal parameters in the spawning and non-spawning season between the diploid and induced triploid Far Eastern catfish, Silurus asotus. The measured triploids were produced by cold shock for 50 min at $4^{\circ}C$ in May 2014, the spawning season of diploid was in May, and the non-spawning season was designated in January. Estradiol and testosterone and gonadosomatic index of diploid were higher than those of induced triploid in spawning season (P<0.05), and those of diploid in spawning season were higher than non-spawning season. On the other hand, thyroid stimulating hormone and thyroxine of induced triploid were higher than those of diploid in spawning season (P<0.05). Erythrocyte count of diploid was higher than that of induced triploid in spawning season and non-spawning seasons. Mean corpuscular volume and mean corpuscular hemoglobin of induced triploid were higher than those of diploid in both seasons (P<0.05). Percentages of total saturated fatty acids and n-3 polyunsaturated fatty acids of induced triploid were higher than those of diploid in spawning season, but those of diploid were higher in non-spawning season (P<0.05). Percentages of total mono unsaturated fatty acids and total n-6 polyunsaturated fatty acids of diploid were higher than those of induced triploids in spawning season, while those of induced triploid in non-spawning season were higher (P<0.05). Therefore, induced triploids in the spawning season tend to concentrate on growth and lipid-synthesization, whereas, diploids concentrate on reproduction and gonadal maturation rather than on growth. In non-spawning season, growth and lipid-synthesization were not significantly different between diploid and induced triploid.

• Journal of Preventive Medicine and Public Health
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• v.37 no.1
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• pp.72-79
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• 2004

Objectives : This cross-sectional study aimed to quantify the relationship between the bone mineral density at the os calcis and the body mass composition in healthy children. Methods : The areal bone mineral density was measured at the os calcis with peripheral dual energy X-ray absorptiometry. The fat free mass, fat mass and percentage fat mass were measured using bioelectric impedance, in 237 Korean children, aged 9 to 12 years. The sexual maturity was determined by self assessment, using standardized series of the 5 Tanner stage drawings, accompanied by explanatory text. Results : From multiple linear regression models, adjusted for age, sexual maturity and height, the fat free mass was found to be the best predictor of the calcaneal bone mineral density in both sexes. About 15 and 20% variabilities were found in the calcaneal bone mineral densities of the boys and girls, respectively, which can be explained by the fat free mass. After weight adjustment, the percentage fat mass was negatively associated with the calcaneal bone mineral density in both sexes. Conclusions : The findings of this study suggest that the fat free mass, among the body compositions, is the major determinant of bone mineral density at the os calcis in Korean children aged 9 to 12 years. Obesity, defined as the percentage fat mass, is assumed to have a negative effect on the calcaneal bone density in children of the same weight.

• Korean Journal of Animal Reproduction
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• v.13 no.2
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• pp.79-84
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• 1989

This study was carried out to investigate the effect of LH-RH and Gn-RH treatment in Holstein cows with ovarian quiescence and follicular cystic ovaries. The cows with ovarian quiescence and follicular cystic ovaries injected intramuscularly with 100$\mu\textrm{g}$, 200$\mu\textrm{g}$ and 400$\mu\textrm{g}$ of LH-RH and 200$\mu\textrm{g}$ and 400$\mu\textrm{g}$ of Gn-RH respectively. The cows was diagnosed by repeated rectal palpation. The plasma progesterone and estradiol-17$\beta$ concentrations were assayed by radioimmunoassay methods. The resutls of this study were summarized as follows : 1. Ovulations were induced after treatment of LH-RH and Gn-RH. The concentrations of progesterone reached small peak level at luteal phase and estradiol-17$\beta$ reached obvious peak level with the development and maturation of the follicle during the periods of degeneration of the corpus luteum, and normal ovarian cycle activity started subsequently. 2. The cows with ovarian quiescence and follicular cystic ovaries were induced ovulation at 38.9$\pm$5.3 hrs. after treatment of LH-RH in 66.7% cows and at 52.7$\pm$7.9 hrs after treatment of Gn-RH in 60.0% cows respectively. 3. The good ovarian responses were indicated in treatment with 200$\mu\textrm{g}$ to 400$\mu\textrm{g}$ of LH-RH than those treated with 100$\mu\textrm{g}$ in cows with ovarian quiescence, and did not show difference of ovarian responses between treatments with 200$\mu\textrm{g}$ to 400$\mu\textrm{g}$ of Gn-RH in cows with follicular cystic ovaries.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.253-258
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• 2002

The androgenic gland secretes a hormone, androgenic gland hormone, which is believed to act on the differentiation of the primary, secondary, and behavioral sex characteristics in most malacostracan crustaceans. Based on the changes in gonado-somatic indexe and histological observation of testis and androgenic gland cell, testicular maturation and spermatogenesis of M. nipponense occurred early in summer (May to July), and generally spermatogenesis was absent in August. It could be, concluded that May to July is the period when adult males of this species are sexually active, and androgenic gland showed signs of increased secretory activity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.704-711
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• 2015

We examined the effects of temperature and light intensity on gametophyte growth of Ecklonia cava Kjellman. The growth of female and male gametophytes was investigated before maturation. Gametophytes prepared from Munseom, Jeju, Korea in October 2014 were separated by sex and maintained under the following conditions: 15℃, 20 μmol·m^-2·s^-1, and a 12-h/12-h light/dark cycle. The experiments were conducted at five temperatures (10, 15, 20, 25, and 30℃) and three light intensities (5, 20, and 40 μmol·m^-2·s^-1). Daily growth rates were estimated by the increase in filamentous frond area. The optimal growth conditions for female gametophytes were 20℃ and 40 μmol·m^-2·s^-1; the optimal conditions for male gametophytes were 15℃ and 20 μmol·m^-2·s^-1. The relative growth rates (RGR) of female and male gametophytes decreased at 25℃ and 30℃, respectively. At 30℃, RGRs of gametophytes decreased by approximately 1.0% day^-1. In addition, RGRs of male gametophytes were higher than those of female gametophytes. These results indicate that female gametophytes were more sensitive to temperature and light intensity than male gametophytes. Moreover, these results suggest that E. cava growth rates could decrease as a result of global warming.

• Korean Journal of Veterinary Research
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• v.42 no.4
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• pp.459-467
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• 2002

The sex steroid hormone progesterone is essential for normal development and maturation of the endometrium in preparation for the embryo implantation and the maintenance of pregnancy. Insulin-like growth factor (IGF) system that is composed of IGF-I, IGF-II, IGF binding proteins (IGFBPs) is also involved in the maintenance of pregnancy. In addition, liver, kidney, and uterus is a target tissue for IGF system. However, the effect of exogenous progesterone on IGF system was not elucidated in female rats. Therefore, we investigated the effect of progesterone on insulin-like growth factors (IGFs) and IGF-binding proteins in serum, liver, kidney, and uterus in female ovariectomized rats. IGFs concentration was measured by radioimmuoassay (RIA) and IGFBPs levels by western ligand blotting(WLB). IGF-I concentration was increased in serum, liver, and uterus, but not in kidney of progesterone-treated ovariectomized rats, compared to control (P<0.05). IGF-II concentration was decreased in liver, but not in serum, kidney, and uterus of progesterone-treated rats, compared to control (P<0.05). IGFBP-3 was increased in serum, but not in liver of progesterone-treated rats, compared to control. IGFBP-2 was decreased in kidney, but not in others tissues of progesterone-treated rats, compared to control. These results suggest that progesterone may exert diverse physiological functions via the tissue-specific regulation of IGFs/IGFBPs system in female rats.