• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.474-481
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• 2010

The sperm collection time, sex steroid hormones, and gonadal development of protandrous black porgy, Acanthopagrus schlegeli, acclimated in freshwater for more than 2 years were investigated to evaluate its reproductive capability. The gonadal development of black porgy reared in seawater and freshwater could each be classified into four successive stages. For black porgy reared in seawater (BSW) as the control, these were the growing (December to February), mature (February to March), spent (March to June), and degeneration and resting (July to December) stages; for black porgy reared in freshwater (BFW), these were the growing (November to January), mature (January to February), spent (February to May), degeneration and resting (June to November) stages. In both BSW and BFW, the plasma cortisol levels were the highest in March. The plasma testosterone (T) levels of BSW and BFW were the highest in March and February, respectively. The plasma estradiol-$17{\beta}$ ($E_2$) levels did not differ significantly between BSW and BFW. The 11-ketotestosterone (11-KT) levels in the plasma of BSW and BFW were the highest in April. Sperm was collectible from March to June in BSW and from February to May in BFW. The results indicated that the gonadal maturation of BFW was about 1 month faster than that of BSW.

• Development and Reproduction
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• v.19 no.1
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• pp.33-41
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• 2015

The gonadosomatic index (GSI), gonadal development and changes in hormones in plasma level of the indoor cultured grunt (Hapalogenys nitens) were investigated by histological study from August 2011 to October 2012. The GSI showed similar trends with gonad developmental stages during the culture periods. Changes in plasma level of estradiol-$17{\beta}$ of female H. nitens reached the highest value before the spawning period, and seasonal changes in plasma level of estradiol-$17{\beta}$ were similar in trends of oocyte developments and GSI changes. Testosterone levels of male H. nitens reached the highest value before and after the spent stage. Ovarian developmental stages of H. nitens could be classified into early growing stage, late growing stage, mature stage, ripe and spawning stage, recovery and resting stage. The testicular developmental stages could be divided into growing stage, mature stage, ripe and spent stage, and recovery and resting stage.

• Journal of Digestive Cancer Research
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• v.11 no.2
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• pp.61-65
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• 2023

Globally, esophageal cancer is the seventh most common cancer, and the male-to-female ratio in esophageal adenocarcinoma (EAC) is significantly imbalanced at 4:1 to 8:1. Obesity, reflux, and smoking are known risk factors for this sex difference; however, fully explaining this remains challenging. Studies have investigated the link between exogenous sex hormones and esophageal cancer occurrence. A meta-analysis revealed a lower risk of EAC in female who had undergone hormone replacement therapy. Androgen-deprivation therapy in patients with prostate cancer was associated with a decreased risk of EAC. Tissue-based studies have reported varied results regarding the relationship between estrogen receptor expression and survival in female patients with esophageal squamous cell carcinoma (ESCC). Circulating hormone studies have suggested that higher testosterone and luteinizing hormone levels decreased EAC risk in men, and free testosterone was inversely correlated in female with ESCC. However, a high androgen-estrogen ratio in male patients with EAC was linked to increased odds of EAC. Sex hormones influence carcinogenesis, affecting cell proliferation, differentiation, metabolism, inflammation, and cell death. The studies were limited by the small sample size and varying hormone measurement methods; thus, future studies with definitive conclusions on the association between esophageal cancer and sex hormones are warranted.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.614-620
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• 2002

The sea bass, Lateoiabrax japonicus is a highly valued fish in aquaculture in South Korea. For establishment of seedling production of sea bass,1 japonicus, we examined change of gonadal development and plasma steroid levels of sea bass reared in indoor tank. Male matured unsimultaneously faster than females and spawning of females took place between the end of January and March. After the spawning period, and until the following January, all the females were in preyitello genesis and in some males, spermatogenetic activity restarted gradually. In October, under reducing photoperiod, cortical alveoli appeared in growing oocyte and the development of spermatogenesis greatly increased. Between October and february, vitellogenesis and spermatogenesis occurred respectively in female and male and gonadosomatic index increased from 4.31 to $24.07\%$ in female and upper 6o/o in male. Also, two sex hormones were analyzed during the course of a reproductive cycle in the sea bass: plasma levels of the gonadal steroid testosterone (T) and estradiol-l7$\beta$ (E_{2}). Variation of the plasma concentrations of T and E, appeared to depend on gonad stages. Plasma T and E, levels were high from November to January, suggesting that an sufficient gonadal stimulation by both hormones may undergoing a processes for the formation of sperm and oocyte.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.701-708
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• 2011

The aim of the present study was to analyze the reductive cycle of the red marbled rockfish Sebastiscus tertius. The analysis was based on annual changes in the gonadosomatic index (GSI), the hepatosomatic index (HSI), histology of the gonadal structure, and plasma sex steroid hormone levels of adult fish from April 1997 to April 1998. GSI of females began to increase in February and peaked ($10.8{\pm}2.72$) in May. HIS levels ($3.41{\pm}0.49$) peaked in February and elevated plasma steroid hormones ($1.47{\pm}0.75$ ng/mL for estradiol-$17{\beta}$ ($E_2$) and $230.7{\pm}27.6$ pg/mL for testosterone (T)) were observed in April. However, in male fish, GSI levels started to increase in August and remained high until November ($0.21{\pm}0.05$). T levels were was also elevated in August and peaked in October ($188.1{\pm}43.5$ pg/mL) and November ($186.8{\pm}28.0$ pg/mL), but started to decline 1 month than the GSI. These results suggest that female ovoviviparious periods span from April to June and amle mating periods occur from November to February.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.6
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• pp.555-563
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• 1999

It is well known that stress induces analgesia. This study was designed to demonstrate the stress-induced analgesia by employing hemorrhage and restraint and to investigate its mechanism and sex difference. The degree of pain was assessed by measuring the magnitude of jaw opening reflex produced by a noxious electrical stimulation in the dental pulp and by measuring the latency to withdraw the tail from a heat ray. Restraint showed an antinociceptive response. A significant increase in pain threshold on bleeding was shown and the increase was larger in male group than in female group. The tail flick latency (TFL) on bleeding after AVP antagonist injection into the ventricle was decreased and the decrease was greater in male rats than in female rats. Castration resulted in a significant reduction of TFL. This effect was reversed by treatment with sex hormones. TFL was decreased during hemorrhage in castrated rats. This response was opposite to that in non-castrated rats. TFL was further decreased during hemorrhage after infusion of AVP antagonist, and there was a significant sex difference. These results suggest that both restraint and hemorrhage produce an antinociception and that, in hemorrhage-induced analgesia, AVP and sex hormones may play an important role and male rats show a greater analgesic response.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.1
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• pp.13-16
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• 2001

Plasma levels of sex steroid hormones in rockfish, Sebastes inermis were examined monthly in relation to gonadosomatic index (GSI) under a controlled water temperature and photoperiod, The GSI of a control group (C) in female began to increase from November and reached a maximum in January, Sample fish under a controlled water temperature and photoperiod (Tr) were divided into a responded group (Tr-r) and a un-responded group (Tr-n) by the gonadal maturation condition and GSI. The GSI of females in Tr-r reached a maximum in March. But the female GSI in Tr-n kept lower than 1.2 during the experimental period. No differences in male GSI were noticed between C and Tr. The $estradiol-17\beta$ and testosterone levels of female plasma in Tr reached a maximum in October, later than those in C. In males, these was no difference in 11-ketotestosterone and testosterone between C and Tr. When rockfish was reared in September under the controlled water temperature and photoperiod which were equivalent to those in July, that is two months earlier, the maturation of females was delayed in comparison with C. This finding suggested that delayed maturation in ovary was caused by the secretion of sex steroid hormones in relation to the water temperature and photoperiod of the hypothalamus-pituitary-gonad axis.

• Proceedings of the KSAR Conference
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• 2005.06a
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• pp.47-54
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• 2005

In boars, unlike the cases in males of other species, gonadal hormones suppress voluntary feed intake. for this reason, barrows, compared with gilts or boars, eat too much feed resulting in excessive fat deposition. Two experiments were performed in the present study to investigate the effects of implantation of Revalor H[Experiment(Exp.) I: 140mg trenbolone acetate(a synthetic androgen) + 14mg estradiol-$17\beta(E_{2}\beta)$] and Compudose(Exp. II; 24mg $E_{2}\beta$) on growth efficiency, carcass characteristics and circulating concentrations of IGF-I and IGF-binding protein-3(IGFBP-3). In Exp. I, sixty-four cross-bred finishing barrows weighing approximately 60kg were randomly divided into eight pens under a 2[control vs Revalor implant] $\times$ 2(ad libitum vs $80\%$ ad libitum feeding) $\times$2[control($103\%$ NRC-recommended level) vs low-energy($87\%$ NRC recommendation) diet] arrangement of treatments. In Exp. II, effects of Compudose were studied using 80 finishing barrows(10 animals/pen). In both Exps., all the animals were slaughtered at 100- to 110-kg body weight. Both Revalor and Compudose implants caused a decrease in feed intake and backfat thickness without affecting major physicochemical characteristics of the carcass and an increase in circulating IGF-I concentration. Moreover, Revalor implant exhibited greater effects than restricted feeding, low-energy diet, or Compudose in these variables. In addition, Revalor implantation suppressed weight gain, but enhanced the feed efficiency without exhibiting any interaction with the diet or feeding. In summary, results suggest that 1) both androgen and estrogen suppress voluntary feed intake and backfat deposition and enhance IGF-I secretion and 2) these effects of the gonadal steroid hormones in growth are likely to be mediated, in part, by IGF-I in finishing barrows.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.5
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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.