• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.3
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• pp.253-261
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• 2012

We investigated the reproductive capacity of starry flounder Platichthys stellatus from the Uljin (UJ) marine ranching area and compared it to that of P. stellatus from the coastal waters of Pohang (PH). In UJ, female gonadosomatic index (GSI) peaked in October ($3.14{\pm}0.87$) and male GSI was high in October and December. In PH, female GSI peaked in January ($18.64{\pm}2.15$) while male GSI began to increase in October and remained high until March. Most ovaries of UJ females were immature with perinucleus oocytes, although the testes of UJ males were ripe in January. Both the ovaries and testes of PH starry flounders were ripe from January to March. The plasma estradiol-$17{\beta}$ ($E_2$) levels of UJ females were highest in October ($4.09{\pm}1.90$ ng/mL) although the testosterone (T) levels of UJ males were highest in December ($3.81{\pm}0.78$ ng/mL) and decreased gradually until April. The $17{\alpha}$,$20{\beta}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}P$) levels of UJ females were not detected. The E2 levels of PH females were highest in December ($36.25{\pm}33.07$ ng/mL) and $17{\alpha}20{\beta}P$ levels were highest in March ($5.51{\pm}0.95$5 ng/mL). The T levels of PH males were highest in December ($4.03{\pm}1.34$ ng/mL) and decreased gradually until October. Taken together, these results suggest that most females from UJ did not reach maturation with a spawning period that was considered to be between December and January.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.4
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• pp.463-470
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• 2011

Gonadotropin-releasing hormone receptor (GnRHR) gene is expressed at the anterior pituitary gland and plays a key role in gonad development. This study aimed to investigate molecular genetic characteristics of the GnRHR gene and elucidate the effects of single nucleotide polymorphisms (SNPs) of GnRHR gene on sex steroid level in Japanese flounder (Paralichthys olivaceus). We used polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and sequencing of the GnRHR gene in 75 individuals. We identified three SNPs in the GnRHR gene: P1 locus (C759A and C830T) in the coding region of exon2 which were both linked together and P2 locus (G984T) in the coding region of exon3, which added a new transcript factor (ADR1) and a new methylation site (CG). Only C830T of P1 leads to amino acid changes Thr266Ile. Statistical analysis showed that P1 was significantly associated with $17{\beta}$-estradiol ($E_2$) level (p<0.01) and gonadosomatic index (GSI) (p<0.05). Individuals with genotype BB of P1 had significantly higher serum $E_2$ levels (p<0.01) and GSI (p<0.05) than those of genotype AA or AB. Another SNP, P2, synonymous mutation, was significantly associated with GSI (p<0.05). Individuals with genotype AB of P2 had significantly higher GSI (p<0.05) than that of genotype AA. In addition, there was a significant association between one diplotype based on three SNPs and reproductive traits. The genetic effects for both serum $E_2$ level and GSI of diplotype D4 were super diplotypes (p<0.05). These results suggest that the SNPs in Japanese Flounder GnRHR are associated with $E_2$ level and GSI.

• Development and Reproduction
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• v.14 no.3
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• pp.199-205
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• 2010

A neurotoxin, 6-hydroxydopamine (6-OHDA) has been widely used to create animal model for Parkinson's disease (PD). The present study was undertaken to examine whether depletion of brain dopamine (DA) stores with 6-OHDA can make alteration in the activities of the testicular steroidogenesis in adult rats. Young adult male rats (3 months old) were received a single dose of 6-OHDA (200 ${\mu}g$ in 10 ${\mu}{\ell}$/animal) by intracerebroventricular (icv) injection, and sacrificed after two weeks. The mRNA levels of steroidogenesis-related enzymes were measured by qRT-PCRs. Serum testosterone levels were measured by radioimmunoassay. Single icv infusion of 6-OHDA significantly decreased the mRNA levels of CYP11A1 (control:6-OHDA group=$1:0.68{\pm}0.14$ AU, p<0.05), CYP17 (control:6-OHDA group=$1:0.72{\pm}0.13$ AU, p<0.05). There were no changes in the mRNA levels of $3{\beta}$-HSD (control:6-OHDA group=$1:0.84{\pm}0.08$ AU) and $17{\beta}$-HSD (control: 6-OHDA group=$1:0.63{\pm}0.20$ AU), though the levels tended to be decreased in the 6-OHDA treated group. Administration of 6-OHDA decreased significantly the mRNA level of StAR when compared to the level of saline-injected control animals (control:6-OHDA group=$1:0.72{\pm}0.08$ AU, p<0.05). Treatment with single dose of 6-OHDA remarkably lowered serum testosterone levels compared to the levels of control group (control:6-OHDA group=$0.72{\pm}0.24:0.13{\pm}0.03ng/m{\ell}$, p<0.05). Taken together with our previous study, the present study demonstrated that the activities of hypothalamus-pituitary-testis hormonal axis could be negatively affected by blockade of brain DA biosynthesis, and suggested the reduced reproductive potential might be resulted in the animals. More precise information on the testicular steroidogenic activities in PD patients and PD-like animals should be required prior to the generalization of the sex steroid hormone therapy to meet the highest standards for safety and efficacy.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.175-180
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• 1999

Blood chemical values and sex steroid hormone concentration of repeat breeder and reproductive disorder in Hanwoo, which were bred in Chunchon areas, were examine to establish the basic physiological maker. The concentrations of albumin, blood urea nitrogen(BUN), calcium(Ca), cholesterol, creatinine, glucose, phosphorous, total protein and triglycerides in repeat breeder and reproductive disorder were 3.28$\pm$0.05 and 3.27$\pm$0.04 g/㎗, 11.07$\pm$0.61 and 12.69$\pm$0.88 mg/㎗, 9.98$\pm$0.10 and 9.56$\pm$0.11mg/㎗, 105.75$\pm$3.57 and 126.78$\pm$5.66mg/㎗, 1.62$\pm$0.05 and 1.65$\pm$0.09 mg/㎗, 67.46$\pm$9.07 and 76.97$\pm$3.76mg/㎗, 6.13$\pm$0.36 and 6.11$\pm$0.26mg/㎗, 5.82$\pm$0.08 and 6.18$\pm$0.08 g/㎗ , 12.82$\pm$1.46 and 15.19$\pm$1.61mg/㎗, respectively. Among the blood chemical values, Ca, cholesterol and inorganic phosphorous levels in repeat breeder and reproductive disorder were slightly higher than those in normal cows. The progesterone levels of pregnancy(0.18~6.56 ng/$m\ell$) and non-pregnancy(0.15~5.46ng/$m\ell$) cows at estrus cycle were showed similar trends from 0 day to 18 days. Those of pregnancy cows were increased gradually from 18 days to 180 days(5.90~7.51 ng/$m\ell$), while those of non-pregnancy cows were dramatically drop at 21 days (0.18$\pm$0.03mg/㎗). The concentrations of estrogen and progesterone in repeat breeder and reproductive disorder were 57.42$\pm$5.03, 56.76$\pm$8.73 pg/$m\ell$ and 6.26$\pm$0.83, 9.41$\pm$1.85 ng/$m\ell$ . respectively. These results indicate that blood chemical values in repeat breeder and reproductive disorder were not greatly difference in normal cows except for Ca, cholesterol, BUN and inorganic phosphorous. Since the progesterone levels in repeat breeder and reproductive disorder was maintained to the luteal phase levels of normal cows, it may cause of failing of conception and next estrus cycle.

• Development and Reproduction
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• v.15 no.4
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• pp.373-383
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• 2011

Tributyltin (TBT) is one of endocrine disrupters which are known as having similar function to sex steroid hormone inducing apoptosis in various tissues of rodents. Recently, it has been reported that TBT induces apoptosis in thymus causing the decreased thymic function, but little is known about the mechanism. To elucidate the mechanism, three-week-old SD female rats were orally administrated with TBT 1, 10, and 25 mg per body weight (kg) and sesame oil as a control for 7 days. On day 8, the thymi were obtained and weighed, and then the number of thymocytes was counted. We also performed H&E staining, TUNEL assay, and Annexin V flow cytometric analysis to examine the apoptosis rates and the structure in the thymus. Next, we investigated the adipogenesis and apoptosis-related mRNA expression levels in the thymi by real-time PCR. The thymic weight and the number of thymocytes were decreased by TBT in a dose-dependent manner. As a result of the H&E staining, the boundary between cortical and medullary area was blurred in the thymi of TBT treated rats compared to those of controls. In the results of TUNEL assay and Annexin V flow cytometric analysis, apoptosis rates in the thymus were increased after TBT treatment. The expression levels of thymic epithelial cell marker genes such as EVA, KGF, AIRE, and IL-7 were significantly decreased in the thymi of TBT treated rats, but $PPAR{\gamma}$, aP2, PEPCK, and CD36 were significantly increased. The expression of $TNF{\alpha}$ and TNFR1 as apoptosis-related genes also was significantly increased after TBT treatment. The present study demonstrates that TBT can increase the expression of adipogenesis and apoptosis-related genes leading to apoptosis in the thymus. These results suggest that the increased adipogenesis of thymus by TBT exposure might induce apoptosis in the thymus resulting in a loss in thymic immune function.