• Ocean and Polar Research
• /
• 제38권1호
• /
• pp.81-88
• /
• 2016

In many fish species, including Nile tilapia (Oreochromis niloticus), gonadal development occurs at the expense of stored energy and nutrients. Therefore, reproductive systems are inhibited by limited food supply. It has been well established that reproductive function is highly sensitive to both metabolic status and energy balance. Nothing is known about the possible mediated connection between energy balance and reproduction. Kisspeptin, a neuropeptide product of the Kiss gene has emerged as an essential gatekeeper of reproduction and may be possibly be linked to energy balance and reproduction in non-mammalians. Thus, in this study, the effect of fasting (10 days) on the expression of kisspeptin and the gonadotropin-releasing hormone (GnRH) gene were assessed in Nile tilapia (male and female) using qRT-PCR. In addition, plasma levels of estradiol-$17{\beta}$ ($E_2$) and 11-ketotestosterone (11-KT) in adult tilapia were measured by ELISA. In male tilapia, fasting reduced Kiss2 and GnRH I mRNA expression in the brain and 11-KT level in comparison with the fed tilapia (p < 0.05). In females, however, there were no significant differences in GnRH I mRNA expression and $E_2$ between fish subjected to fasting and those fed (p > 0.05). These data indicate the impact of nutritional states on kisspeptin as a potential regulatory mechanism for the control of reproduction in male Nile tilapia.

• Clinical and Experimental Reproductive Medicine
• /
• 제21권3호
• /
• pp.297-303
• /
• 1994

The effect of radiation on the steroidogenesis of rat ovary was investigated. For this purpose, female rats aged 7-8 weeks were exposed to a single dose of ${\gamma}$ radiation(320 rad or 800 rad) by the cobalt-60. At fourth(day of the first estrus) and eighth(day of the second estrus) days after irradiation, the concentrations of serum steroid hormones were determined by radioimmunoassays (RIA). The correlation between survival rate(Y) and radiation dose(X) was Y=-0.06X+100(r=0.89, n=10). Lethal dose$(LD)_{50(30)}$ and $LD_{20(30)}$ were 833.33rad and 333.33rad respectively. The weights of body and ovary was decreased significantly by the $LD_{50(30)}$ irradiation during the 4 days, but both weights were recovered at day 8. The serum levels of 17a-hydroxyprogesterone(170HP) and estradiol($E_2$) in the irradiated rats were not generally different from those of control. However, the levels of testosterone(T) and 19-norterstosterone(19NT) in the irradiated rat at $LD_{50(30)}$ and $LD_{20(30)}$ radiation doses were decreased, while progesterone levels in serum of the irradiated rats were slightly increased. These results suggest that irradiation may inhibit the first step of steroidogenesis, especially the conversion of P to T, in the rat ovary.

• Clinical and Experimental Reproductive Medicine
• /
• 제32권3호
• /
• pp.199-206
• /
• 2005

연구목적: 난포가 폐쇄되는 동안의 생화학적 변화를 규명하기 위하여 미성숙 돼지의 정상 및 폐쇄 난포 내 lactate dehydrogenase (LDH) 활성도 변화 및 동일 난포액 내 스테로이드호르몬의 농도변화를 알아보기 위하여 본 연구를 시행하였다. 재료 및 방법: 난포액 (FF), 과립세포 (GC), 협막세포 (TC) 내 LDH의 활성도를 측정하였으며, 난포액 내 progesterone ($P_4$), testosterone (T), estradiol ($E_2$)의 농도변화를 방사면역측정법으로 정량하였다. 결　과: 정상 및 폐쇄 난포에서 $P_4$의 농도변화를 보이지 않았다. 그러나 폐쇄 난포액 내 T의 농도($3.85{\pm}1.50ng/ml$)는 정상 난포 ($1.29{\pm}0.54ng/ml$)에 비해 현저히 높았으며 정상 난포 내 $E_2$의 농도 ($43.29{\pm}19.51ng/ml$) 는 폐쇄 난포 ($18.82{\pm}7.27ng/ml$)에 비해 현저히 높은 것으로 나타났다. 정상 난포액 내 $P_4$의 농도는 난포의 크기에 정의 상관관계 (r=0.75)를 보였다. 정상 난포 내 T:$P_4$의 비율 ($8.14{\pm}3.35$)은 폐쇄 난포 ($1.39{\pm}0.60$)에 비해 현저히 높았으며, 정상 TC ($433.63{\pm}102.40{\mu}U/{\mu}g$ DNA) 및 FF ($246.86{\pm}58.96{\mu}U/{\mu}l$) 내 LDH 활성도는 폐쇄 난포 (각각 $83.7{\pm}10.5$와 $38.71{\pm}9.00$)에 비해 현저히 높게 나타났다. 정상 난포의 GC 및 FF 내 LDH 활성도는 $E_2$의 농도와 부의 상관관계를 보였지만, 폐쇄 난포의 TC 내 LDH 활성도는 $P_4$, T, $E_2$의 농도에 대해 정의 상관관계를 나타내었다. 결　론: 본 실험의 결과, 미성숙 돼지 난포의 폐쇄는 TC 내 LDH 활성도 감소와 밀접한 관계를 갖는 것으로 사료된다.

• Clinical and Experimental Reproductive Medicine
• /
• 제45권3호
• /
• pp.116-121
• /
• 2018

Objective: The aim of this study was to compare serum fetuin-A levels and oxidative stress markers, as indicators of insulin resistance, in women with polycystic ovary syndrome (PCOS) and in healthy controls. Methods: This prospective case-control study included 46 patients with PCOS and 48 age- and body mass index-matched control women. Levels of serum hormones, fetuin-A, and oxidative stress markers were measured in blood samples taken during the early follicular period from each participant. Results: Follicle-stimulating hormone (FSH), luteinising hormone (LH), total testosterone levels, and the LH/FSH ratio were found to be significantly higher in women with PCOS than in controls. Serum total antioxidant status, total oxidant status, and oxidative stress index parameters all indicated significantly higher levels of oxidative stress in PCOS patients than in controls. Serum fetuin-A levels, which were analyzed as an indicator of insulin resistance, were higher in the PCOS group than in the control group ($210.26{\pm}65.06{\mu}g/mL$ and $182.68{\pm}51.20{\mu}g/mL$, respectively; p= 0.024). Conclusion: The data obtained from the present study suggest that higher levels of both serum fetuin-A and oxidative stress markers might be related with PCOS.

• 한국육종학회지
• /
• 제43권1호
• /
• pp.1-13
• /
• 2011

Low temperature stress is one of the major negative factors affecting vegetative and reproductive growth of rice. To better understand responses of rice plants to low temperature we analyzed transcriptome expression patterns in glumous flower of cold-tolerant japonica rice variety, Stejaree45, and cold-susceptible variety, HR19621-AC6 at booting stage under cold water irrigation. A total of 2,411 probes were differentially expressed by low temperature in glumous flowers of the two varieties. Some important genes involved in hormone biosynthesis showed variety-specific regulation. Expression of GA20ox3 and GA2ox, among the genes involved in GA biosynthesis, was regulated differentially in the two varieties. Among the genes involved in IAA biosynthesis, YUCCA1 and TAA1:1 showed variety-specific regulation. Among the genes involved in cytokinin biosynthsis and signaling, expression of LOG, HK1 and HK3 was significantly down-regulated only in the cold-susceptible variety. Among the genes involved in ABA biosynthesis, NSY and AAO3 were down-regulated only in the cold-tolerant variety. In general, genes involved in GA, IAA and cytokinin biosynthesis responded to cold temperature in such a way that capacity of those bioactive hormones is maintained at relatively higher levels under cold temperature in the cold-tolerant variety, which can help minimize cold stress imposed to developing reproductive organs in the cold-tolerant variety.

• Animal Bioscience
• /
• 제35권11호
• /
• pp.1666-1674
• /
• 2022

Objective: Letrozole, a potent aromatase inhibitor, is known to have the potential to modify male reproductive function by altering sex hormone levels. This study aimed to evaluate the semen and testicular characteristics and hormonal profile of aged Mrakhoz bucks (Capra hircus) treated with letrozole. Methods: Twelve Markhoz male goats, aged between 4.5 to 5.5 years with an average body weight (BW) of 61.05±4.97 kg were used for the study. Animals were randomly divided into two equal groups and subcutaneously received either 0.25 mg/kg BW of letrozole or a control every week for 2 months. The semen collections were performed every 10 days, and blood samples and testicular biometric records were collected at 20 days intervals. Results: Letrozole causes increased testosterone and follicle-stimulating hormone levels, testosterone to estradiol ratio, semen index and reaction time during the period from 20th to 60th days (p<0.05). Furthermore, letrozole-treated bucks had higher semen volume, sperm concentration, and total sperm per ejaculate from 30th to 60th days (p<0.05). However, no differences occurred between the groups in scrotal circumference, relative testicular volume, semen pH, abnormality, acrosome integrity, and membrane integrity of sperm during the study (p>0.05). The serum luteinizing hormone levels, sperm viability, motility, and progressive motility increased, and estradiol levels decreased after 40th to 60th days of letrozole treatment (p<0.05). Conclusion: Letrozole application to aged Markhoz bucks provokes reproductive hormonal axis which, in turn, induces enhancement of semen production and quality.

• Clinical and Experimental Reproductive Medicine
• /
• 제50권3호
• /
• pp.192-199
• /
• 2023

Objective: This study was conducted to investigate chromosomal abnormalities and their correlations with clinical and radiological findings in females with primary amenorrhea (PA). Methods: Detailed forms were recorded for 470 females, including the construction of three-generation pedigrees. Peripheral venous blood was drawn, with informed consent, for cytogenetic analysis. Results: An abnormal karyotype was found in 16.38% of participants. The incidence of structural abnormalities (6.8%) exceeded that of numerical abnormalities (6.15%). Turner syndrome represented 45% of all numerical abnormalities. Furthermore, the Y chromosome was detected in 5% of females with PA. Among the structural chromosomal abnormalities detected (n=32) were mosaicism (25%), deletions (12.5%), isochromosomes (18.75%), fragile sites (3.12%), derivatives (3.12%), marker chromosomes (3.12%), and normal variants (29.125%). An examination of secondary sexual characteristics revealed that 29.6% of females had a complete absence of breast development, 29.78% lacked pubic hair, and 36.88% exhibited no axillary hair development. Radiological findings revealed that 51.22% of females had a hypoplastic uterus and 26.66% had a completely absent uterus. Abnormal ovarian development, such as the complete absence of both ovaries, absence of one ovary, one absent and other streak, or both streak ovaries, was observed in 69.47% of females with PA. Additionally 43.1%, 36.1%, 67.4%, and 8% of females had elevated levels of serum follicle-stimulating hormone, luteinizing hormone, thyroid-stimulating hormone, and prolactin, respectively. Conclusion: This study underscores the importance of karyotyping as a fundamental diagnostic tool for assessing PA. The cytogenetic correlation with these profiles will aid in genetic counseling and further management of the condition.

• Asian-Australasian Journal of Animal Sciences
• /
• 제27권4호
• /
• pp.479-487
• /
• 2014

Leptin plays an important role in energy homeostasis and reproductive function in fish, especially in reproduction. Migrating fish, such as salmonoids, are affected by external environmental factors, and salinity changes are a particularly important influence on spawning migrations. The aim of this study was to test whether changes in salinity affect the expression of leptin, estrogen receptors (ERs), and vitellogenin (VTG) in chum salmon (Oncorhynchus keta). The expression and activity of leptin, the expression of ERs and VTG, and the levels of estradiol-$17{\beta}$ and cortisol increased after the fish were transferred to FW, demonstrating that changes in salinity stimulate the HPG axis in migrating female chum salmon. These findings reveal details about the role of elevated leptin levels and sex steroid hormones in stimulating sexual maturation and reproduction in response to salinity changes in chum salmon.

• 한국발생생물학회지:발생과생식
• /
• 제2권2호
• /
• pp.115-133
• /
• 1998

지난 반세기 동안내분비 장애물질의 제한없는 생산과 무분별한 소비, 방출, 폐기는 물, 흙, 공기 등 자연을 오염시켜 왔다. 그 결과 생태계의 야생동물이 오염되어, 생식과 발생의 이상이 일어나고, 멸종이 예견되기에 이르렀다. 또한 동물 자신은 물론, 후세대에 내분비계의 교란을 일으켜 정상적인 성생활, 발생과 생식의 기형, 정자수 감소 등의 불임유발, 성행동, 신경계와 면역계의 이상, 암까지 유발하는 것으로 알려지고 있다. 암이 개체의 사멸을 일으키는 반면, 내분비 장애물질은 체내에 잔류되며 대를 이어 전달되고, 사멸하여도 환경의 오염원이 되어 먹이사슬로 축적된다는 의미에서 야생동물은 물론 인간의 미래를 어둡게 만든다고 판단되고 있다. 그러므로 이들이 야생동물의 생식과 발생에 미치는 영향, 먹이사슬내의 이동 및 오염 확산을 개관하고자 하였다. 또한 이에 대처하기 위한 국내외 연구동향을 기술하고, 또 중요한 물질의 생산 현황을 요약하고, 발생과 생식을 전공하는 연구자 제위에게 관심을 유도하고자 하였다.

• BMB Reports
• /
• 제36권1호
• /
• pp.28-34
• /
• 2003

Breast cancer is the most prevalent cancer among women in Western countries, and its prevalence is also increasing in Asia. The major risk factor for breast cancer can be traced to reproductive events that influence the lifetime levels of hormones. However, a large percentage of breast cancer cases cannot, be explained by these risk factors. The identification of susceptibility factors that predispose individuals to breast cancer (for instance, if they are exposed to particular environmental agents) could possibly give further insight into the etiology of this malignancy and provide targets for the future development of therapeutics. The most interesting candidate genes include those that mediate a range of functions. These include carcinogen metabolism, DNA repair, steroid hormone metabolism, signal transduction, and cell cycle control. We conducted a hospital-based case-control study in South Korea to evaluate the potential modifying role of the genetic polymorphisms of selected low penetrance genes that are involved in carcinogen metabolisms (i.e., CYP1A1, CYP2E1, GSTM1/T1/P1, NAT1/2, etc.), estrogen synthesis and metabolism (i.e., CYP19, CYP17, CYP1B1, COMT, ER-$\alpha$, etc.), DNA repair (i.e., XRCC1/3, ERCC2/4, ATM, AGT, etc.), and signal transduction as well as others (i.e., TGF-$\beta$, IGF-1, TNF-$\beta$, IL-1B, IL-1RN, etc.). We also took into account the potential interaction between these and the known risk factors of breast cancer. The results of selected genes will be presented in this mini-review.