• 한국환경보건학회지
• /
• 제41권3호
• /
• pp.147-162
• /
• 2015

Objectives: The objective of this review was to summarize the primary role of three representative endocrine axes in aquatic vertebrates and discuss the effects on endocrine systems and their interactions in teleost fish after exposure to environmental contaminants. Methods: We summarized individual traits and mechanisms for hormonal and transcriptional interactions between the hypothalamic-pituitary-gonad (HPG), hypothalamic-pituitary-thyroid (HPT), and hypothalamic-pituitary-adrenal (HPA) axes in fish. We also provided a brief discussion on the effects of nonylphenol-induced toxicity on endocrine systems and their interactions in fish as a demonstration of holistic explanation. Results: Currently-available data showed that thyroid dysfunction is associated with reproductive toxicity due to changes in steroidogenic gene expressions and sex hormone levels as well as gonad glands in fish. As an example, we demonstrated that exposure to nonylphenol could induce estrogenicity in male fish by decreasing thyroid hormones, which contributes to increased aromatase expression. Although the mechanisms are complicated and involved in multiple ways, a number of studies have shown that sex steroids influence the HPT axis or the HPA axis in fish, indicating bi-directional crosstalk. Critically missing is information on the primary target or toxicity mechanisms of environmental contaminants among the three endocrine axes, so further studies are needed to explore those possibilities. Conclusions: This review highlights the interactions between the HPG, HPT, and HPA axes in fish in order to better understand how these endocrine systems could interact with each other in situations of exposure to endocrine disrupting chemicals.

• The Korean Journal of Physiology and Pharmacology
• /
• 제4권2호
• /
• pp.81-90
• /
• 2000

The types of $K^+$ channel which determine the pattern of spontaneous action potential (SAP) were investigated using whole-cell variation of patch clamp techniques under current- and voltage-clamp recording conditions in rat clonal pituitary $GH_3$ cells. Heterogeneous pattern of SAP activities was changed into more regular mode with elongation of activity duration and afterhyperpolarization by treatment of TEA (10 mM). Under this condition, exposure of the class III antiarrhythmic agent E-4031 $(5\;{\mu}M)$ to $GH_3$ cells hardly affected SAP activities. On the other hand, the main $GH_3$ stimulator thyrotropin-releasing hormone (TRH) still produced its dual effects (transient hyperpolarization and later increase in SAP frequency) in the presence of TEA. However, addition of $BaCl_2$ (2 mM) in the presence of TEA completely blocked SAP repolarization process and produced membrane depolarization in all tested cells. This effect was observed even in TEA-untreated cells and was not mimicked by higher concentration of TEA (30 mM). Also this barium-induced membrane depolarization effect was still observed after L-type $Ca^{2+}$ channel was blocked by nicardipine $(10\;{\mu}M).$ These results suggest that barium-sensitive current is important in SAP repolarization process and barium itself may have some depolarizing effect in $GH_3$ cells.

• Clinical and Experimental Reproductive Medicine
• /
• 제25권2호
• /
• pp.199-205
• /
• 1998

흰쥐 난소에서의 Luteinizing hormonoe (LH) subunit 유전자 발현과 LH polypeptide의 존재를 조사하였다. 이를 위해 LH subunit들에 대한 역전사 중합효소연쇄반응 (RT-PCR)을 시행하고, 난소내 LH 함량을 방사면역측정법으로 정량하였다. 뇌하수체와 정소에서 공통적으로 존재하는 LH-$\beta$ subunit$(LH-\beta})$의 exon에 해당되는 primer를 사용하여 RT-PCR을 시행한 결과 흰쥐 난소에서도 뇌하수체, 정소와 같이 306 bp band가 확인되었고, 정소특이적인 exon에 해당되는 primer를 사용한 결과 정소와 난소에서 예상대로 428 bp band가 검출되었다. 또한 LH, FSH, TSH 그리고 hCG에서 공통적으로 발현되는 common $\alpha$-subunit $(C_\alpha)$의 전사물질도 PCRdml 의해 증폭되었다. 방사면역측정법에서는 LH standard curve와 난소추출물을 사용한 curve가 동일하게 sigmoid 형태를 보임으로서 흰쥐 난소내에 immunoreactive LH가 존재함이 증명되었다. 인위적으로 성적인 성숙을 유도한 PMSG 주사 동물에서 혈중 LH 수준은 주사 후 48시간에 preovulatory LH surge와 유사한 최고 수준을 나타냈으나, 난소내 LH 함량의 경우 주사 24시간 후부터 급격히 감소하여 주사 48, 72시간군까지도 낮은 수준이 유지되었다. 이 결과는 흰쥐 난소의 LH가 생리적으로 조절되고 그 조절방식이 뇌하수체에서와는 다를 가능성을 시사하는 것이다. 본 연구는 흰쥐의 난소에서 LH가 유전자가 발현됨을 최초로 보고한 것이며, LH의 경우 내분비적 경로 (endocrine; 뇌하수체로 부터의 LH)외에도 국부적 경로 (autocrine이나 paracrine; 난소내에서 합성되는 LH)를 통해 난소의 생리와 기능 조절을 담당함을 시사한다.

• Animal cells and systems
• /
• 제15권4호
• /
• pp.310-314
• /
• 2011

The Banna miniature pig (BNMP) is a representative miniature pig breed in China. Even though BNMP dwarfism is obvious, its underlying causative mutations remain unknown. In this study, the BNMP and Large White pig (LWP) serum growth hormone (GH) and insulin-like growth factor (IGF-1) levels were detected by ELISA and compared. BNMP serum IGF-1 levels were significantly lower than LWP levels (P<0.05). The miniature condition may arise from mutations in the GH and GH receptor (GHR) genes. Therefore, GH and GHR cDNA from the BNMP were cloned into a pMD18-T vector by RT-PCR using the total RNA obtained from the BNMP's pituitary and liver tissues. Sequencing results indicated that the open reading frame of the BNMP GH gene is composed of a 26-residue signal peptide and a 191-residue mature peptide. The coding sequence of the BNMP GHR gene contained 639 amino acids, including a signal peptide that is 18 amino acids long. Two amino acid substitutions, A09V and R22Q, were found in the signal peptide of the GH gene. Additionally, the S104P mutation was found in the BNMP's mature GH protein. Four mutations in the cytoplasmic domain of GHR may influence the downstream signal transduction of GHR, which needs further experimental evidence.

• 한국수정란이식학회지
• /
• 제28권2호
• /
• pp.149-155
• /
• 2013

Mullerian inhibiting substance (MIS) is a member of the TGF-${\beta}$ (transforming growth factor-${\beta}$) family whose members play key roles in development, suppression of tumour growth, and feedback control of the pituitary-gonadal hormone axis. MIS is expressed in a highly tissue-specific manner in which it is restricted to male Sertoli cells and female granulose cells. The serum levels of MIS in prenatal and postnatal ICR mice were measured using the enzyme-linked immuno-solvent assay (ELISA) using the MIS/AMH antibody. Mice were grouped by age: the significant periods were at the onset of development. During sex organ differentiation, no remarkable difference between female and male foetus MIS serum levels (both<0.1 ng/ml) was observed. However, MIS serum levels in pregnant mice markedly changed (4.5~12.2 ng/ml). After birth, postnatal female and male mice serum MIS levels changed considerably (male: <0.1~138.5 ng/ml, female: 5.3~103.4 ng/ml), and the changing phase were diametrically opposed (male: decreasing, female: fluctuating). These findings suggest that MIS may have strong associations with not only develop-ment but also puberty. For further studies, establishing the standard MIS serum levels is of importance. Our study provides the basic information for the study of MIS interactions with reproductive organ disability, cancer, and the effect of other hormone or menopause. We hypothesise that if MIS is regularly injected into middle-age women, meno-pause will be delayed. We detected that serum MIS concentration curves change with age. The changing phase is different between males and females, and this difference is significant after birth. Moreover, MIS mRNA is expressed during the developmental period (prenatal) and also in the postnatal period. This finding indicates that MIS may play a significant role in the developmental stage and in growth after birth.

• Clinical and Experimental Reproductive Medicine
• /
• 제20권2호
• /
• pp.125-130
• /
• 1993

Polycystic ovarian syndrome (PCOS) patients have a characteristic of high leuteinizing hormone (LH) to follicle -stimulating hormone (FSH) ratio. Usually, human menopausal gonadotropin (hMG) is used to induce ovulation in clomiphene citrate-resistant PCOS patients. However, HMG contains two components, namely, LH and FSH, with 50%, respectively. Therefore, FSH is theoretically recommended to stimulate follicular maturation. From the pituitary, LH is secreted by pulsatile pattern. So, we have been using intermittent subcutaneous injection of pure FSH for ovulation induction in 10 PCOS patients from March, 1990 to August, 1992. We obtained good results by intermittent subcutaneous injection of pure FSH. Ovulation is 100% per patient, and 88.2% per cycle. Pregnancy rate is 80% per patient, and 23.5% per cycle. Ovarian hyperstimulation syndrome (OHSS) is 50% per patient, 41.2% per all cycles, and 46.7% per all ovulated cycles. In comparison with HMG, pregnancy rate per cycle is relatively low. But, ovulation rate and pregnacy rate per person is higher than HMG. Because of the strict check of ovaries by the vaginal ultrasonography, OHSS rate is relatively high.

• Animal cells and systems
• /
• 제3권4호
• /
• pp.385-391
• /
• 1999

Changes in the levels of prostaglandian F$_{2a}$ (PGF$_{2a}$) and E$_2$ (PGE$_2$) in culture medium during in vitro ovulation of Rana dybowskii follicles were examined. The ovulation was induced by frog pituitary homogenate (FPH) or TPA (12-O-tetradecanoylphorbol-13-acetate, a protein kinase activator) and the levels of PGs were measured by radioimmunoassay. When the ovarian follicles were cultured, only a few oocytes were ovulated by 12 h, but half of them were ovulated by 24 h in response to FPH, whereas around 30% of oocytes were ovulated by 12 h and maximum ovulation (around 50%) occurred by 24 h in response to TPA. Without any stimulation (control), no ovulation occurred. TPA elevated the level of PGF$_{2a}$ to high levels when compared to control (basal levels), but the increase by FPH was less evident. Likewise, the levels of PGE$_2$ increased markedly in response to TPA, but rather decreased by FPH treatment. Interestingly, PGF$_{2a}$ induced ovulation but PGE$_2$ suppressed FPH- or PGF$_{2a}$-induced oocyte ovulation. Basal levels of PGs Increased steadily during culture. When theca/epithelium (THEP) layer and granulosa cell-enclosed oocytes (GCEOs) were separated by microdissection and cultured independently, higher levels of both PGs were secreted by THEP than by GCEOS. Synthesis of PGs by follicle or follicular components was strongly suppressed by exogenous cAMP or indomethacin. These results suggest that: 1) PGF$_{2a}$ plays an important role in Rana ovulation, 2) protein kinase C is involved in PGs production, and 3) thecal epithelium layer is responsible for the PGs production in Rana.

• 한국동물학회지
• /
• 제33권1호
• /
• pp.53-62
• /
• 1990

양서류의 여포난자를 생체외에서 배양하면서 호르몬을 처리하면 난자의 성숙(핵붕괴)을 일으킨다. 본 연구는 북방산개구리의 여포난자를 배양하면서 난자내 단백질 분해효소들의 활성변화를 유도하여 이것이 난자의 성숙에 어떠한 영향을 미치는가를 조사하였다. chymotrypsin의 저해제로 알려진 N$\alpha$ -tosyl-L-phenylalanine-chloromethyl-ketone(TPCK)을 배양액에 처리하면 비교적 낮은 농도(0.001-1 $\mu$M)에서는 호르몬의 도움없이도 난자의 성숙을 유도하나 높은 농도 (100 $\mu$M)에서는 호르몬에 의한 난자의 성숙까지도 억제하는 이중적인 효과를 나타내었다. Trypsin의 저해제인 N$\alpha$ -tosyl-L-phenylalanine-chloromethyl-ketone(TPCK)은 성숙유도능력이 없을 뿐 아니라 progesterone에 의한 난자의 성숙을 억제하였다. Trypsin을 직접 처리했을 때에는 농도에 의존하여(0.001-1$\mu$g/2ml) 호르몬의 도움없이도 난자의 성숙을 유도함을 발견하였다. TLCK나 TPCK의 억제효과는 성숙 초기에만 나타났다. 본 결과는 양서류 난자의 성숙조절 과정에 몇종의 단백질 분해효소들이 참여한다는 것을 시사해주고 있다.

• Journal of Oral Medicine and Pain
• /
• 제32권2호
• /
• pp.201-210
• /
• 2007

많은 질병들과 기존에 존재하는 신체적인 질병들은 스트레스로 인해 발병되거나 크고 작은 스트레스의 영향으로 악화된다. 스트레스의 연구에 호르몬을 사용하는 기본은 신체의 대부분 시스템이 스트레스를 받는 동안 변화를 보인다는 것과 이러한 변화에 호르몬이 스트레스와 확실하게 연관되어 있다는 것을 관찰하는 것이다. 개념적으로 스트레스에 있어서 교감신경계와 시상하부-뇌하수체-부신축의 활성화가 중심적인 역할을 한다는 것이 호르몬의 변화를 측정해야 할 충분한 근거를 제공한다. 에피네프린과 노르에피네프린과 같은 카테콜라민, 코티졸, 테스토스테론 그리고 성장호르몬 등은 스트레스에 예민한 반응을 보인다. 한편 스트레스 연구를 위한 타액표본은 혈액이나 요의 표본과는 달리 스트레스를 주지 않고도 표본을 얻을 수 있으며 신체적인 구속이나 윤리적인 문제 등을 염려하지 않고도 채취가 가능하다는 장점이 있다. 타액내의 호르몬의 수치는 혈액내의 호르몬 수치를 잘 반영하므로 스트레스와 관련된 구강안면통증의 연구에 있어서 타액내의 스트레스 호르몬에 활용도는 매우 높으리라고 사료된다.

• Clinical and Experimental Reproductive Medicine
• /
• 제21권3호
• /
• pp.241-245
• /
• 1994

Despite increasing success rate of IVF, poor response to ovarian stimulation remains a problem. So, attempts to improve ovarian responses, for example, by using combined gonadotropin-releasing hormone analogue(GnRH-a) and human menopausal gonadotropin(hMG) have shown limited success. It is reported that response of granulosa cells in vitro to FSH is stimulated by co-incubation with IGF-l, and IGF-l production can be increased by growth hormone. This suggest that combination regimen of G.H. and hMG may augment follicle recruitment. In fifteen patients who had previous history of poor ovarian response to gonadotropin stimulation after pituitary suppression with mid -luteal GnRH-a, the effectiveness of cotreatment with G.H. in IVF program was evaluated using a combination regimen of G.R. and hMG at Korea University Hospital IVF Clinic. Ovarian responses to gonadotropin stimulation in control and GH-treated cycles assessed by total dose and duration of hMG treatment, follicular development and peak $E_2$ level, number of eggs retrieved, and fertilization rates were also assessed. In each group, serum and follicular fluid IGF-1 concentrations on day of egg collection were measured by RIA after acidification and extraction by reveresed phase chromatography. Patients receiving G.H. required fewer days and ampules of gonadotropins, developed more oocytes, and more embryos transferred. But, the differences were not statistically significant, except the duration of hMG treatment. Our data showed a significantly higher concentration of IGF-l in the serum, not in the follicular fluid, of patients treated with G.H. compared with control group. These data suggest that growth hormone treatment does not improve the ovarian response in women with limited ovarian reserve to gonadotropin stimulation for IVF.