Effects of Foreign GnRH cDNA on Reproductive Activity in Male Golden Hamsters: Analysis of Individuals

최돈찬,조병남 한국발생생물학회 2003 발생과 생식 Vol.7 No.1

성선자극호르몬 분비호르몬은 시상하부에서 분비되며, 포유동물의 생식에 중추적인 역할을 담당한다. 골든 햄스터는 계절적으로 번식하는 포유동물이며, 생식 활동은 광주기(하루 중 낮의 길이)에 의해 결정된다. 장주기(12.5 시간 이상의 빛)는 생식 능력을 유지시키지만, 단주기(12시간 이하의 빛)는 생식 기능을 억제한다. 성선자극호르몬 분비호르몬과 광주기의 상호 관계를 자세히 조사하기 위하여 랫트 성선자극호르몬 분비호르몬 cDNA를 포함하는 벡터를 여러 농도 Gonadotropin releasing hormone(GnRH), which is secreted from the hypothalamus, has a pivotal role in the reproduction of mammals. Golden hamsters are seasonal breeding mammal and their sexual activity is determined by photoperiod(length of light per day). Long photoperiod(LP, 12.5 hours of light) maintains the reproductive activity and short photoperiod(SP, 12 hours of light) suppresses it. In order to investigate in detail, the sexual activity was individually examined in SP-housed male golden hamsters received a vector at three different concentrations which contains rat GnRH cDNA. The gonadal regression was significantly(P<0.05) accelerated by the highest concentrations of the vector at 8 and 10 weeks after the treatment in comparison to the other groups. In the light of pulsatile release of GnRH in maintaining reproductive activity, the vector containing GnRH cDNA might secrete the GnRH in a constant high level. These results suggest that the GnRH-containing vector might desensitize the anterior pituitary, leading to acceleration or testicular regression.

생식능력이 퇴화된 골든 햄스터에서 clock 유전자의 발현

최돈찬 龍仁大學校 2009 용인대학교 논문집 Vol.27 No.-

Reproduction of golden hamsters is controlled by the photoperiod. long photoperiod maintains the sexual activity but short photoperiod regresses it. The daily photoperiod information is also reflected by the circadian rhythms, which are governed by the suprachiasmatic nucleus(SCN) of the hypothalamus. There are several genes displaying those daily rhythms. Among them, the expression of a clock gene was investigated in the SCN of the sexually involuted male hamsters. As a result, the rhythmic changes of expression of the clock gene were clear, with a peak at the right after lights on. Then the expression of the clock gene was slowly reduced toward the rest of the light phase. During the dark period it is gradually increased. This daily oscillation is different from the previous report, showing no fluctuations in the hamsters exposed to long photoperiod and timely changes in the animals exposed to short photoperiod in the same animal. Taken together, with the changes of the expression of other circadian genes reported in various mammals, the present finding suggests tissue-specific, species-dependent, sexual activity dependent expression of the clock gene.

자연과학대학 재학생의 실태 및 의식 조사

최돈찬 용인대학교 학생생활연구소 2010 학생생활연구 Vol.18 No.-

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광주기와 멜라토닌이 수컷 골든 햄스터의 생삭능력에 미치는 영향 : Influence of Photoperiod and Malatonic on Reproductive Activity in Male Golden Hamster

최돈찬,임시내 용인대학교 자연과학연구소 2001 自然科學硏究所論文誌 Vol.6 No.1

Photoperiod(length of light per day) is a major factor in determining sexual activity in golden hamsters. Long photoperiod(LP, ≥ 12.5 hours of light per day) maintains the sexual activities whereas short photoperiod(SP, ≤ 12 hours of light per day) suppresses them. The information of photoperiod is transmitted to the reproductive system by melatonin that is secreted from the pineal gland. Thus reproductive hormones are investigated in male golden hamsters that are housed in LP or SP and that are injected daily with melatonin in the morning or evening. Reproductive functions are active in the animals housed in LP and injected with melatonin in the morning and inactive in the animals housed in SP and injected in the evening. Paired testicular weights were markedly reduced in the sexually inactive animals. Serum FSH and LH levels were also lower in the sexually inactive animals than in the sexually active animals. When they were measured in the serum taken continuously from the same animal, both LH and FSH displayed pulsatile pattern in sexually active animals, but the pulsation was disappeared in sexually inactive animals. Moreover, the mean values of FSH and LH in regressed animals were much less. The histological examination of regressed testes showed reduction of tubular lumen diameter, interstitial space, and Leydig cell number. Taken together, the effects of photoperiod and melatonin treatment were reflected in reproductive endocrine system. The results suggest that their influence may be mediated by gonadotropin releasing hormone. Therefore, the impact of photoperiod(via melatonin) on GnRH neuronal system needs to be investigated.

수컷 골든 햄스터의 생식기능 관련 혈청 바이오마커

최돈찬,한은희 龍仁大學校 2010 용인대학교 논문집 Vol.28 No.-

The reproduction of mammals is regulated by the gonadotropin releasing hormone(GnRH) secreting from the hypothalamus. This neurohormone affects its impacts on hypothalamus-pituitary-gonad axis, and controls the reproductive activities. The breeding functions in some of the mammals are affected by the photoperiod, whose proper treatments lead to the dichotomy of reproductively active and inactive activities. The proteins in sera of male golden hamsters were examined by applying two dimensional electrophoresis in the sexually alterate incidents. Among many spots, a surely and uniquely stained point was discovered in sexually active hamsters but not in sexually inactive hamsters. The spot could be utilized as a putative biomarker, referring to reproductive functions at least in these animals. Therefore, besides the elements using in existing diagnosis, it is suggested that the protein be used as an additional useful tool in determining the reproductive potential.

High Performance Liquid Chromatography를 이용한 멜라토닌 측정

최돈찬,임시내 용인대학교 2001 용인대학교 논문집 Vol.19 No.-

골든 햄스터 수컷의 생식능력에 미치는 외인성 성선자극호르몬 분비호르몬의 영향 : 개체추적 track of individuals

최돈찬 龍仁大學校 2003 용인대학교 논문집 Vol.21 No.-

Reproductive activity in mammals is regulated by gonadotropin releasing hormone(GnRH), which is secreted from the hypothalamus. Golden hamsters are seasonal breeders and their sexual activity is determined by photoperiod (length of light per day). Long day(LD. ≥12.5 hours of light ) maintains the reproductive activities and short day(SD. ≤12 hours of light ) suppresses them. Thus, the sexual activity was individually examined in SD-housed male golden hamsters received a vector at three different concentrations which contained the gene expressing GnRH. The gonadal regression was accelerated by the highest concentrations of the vector in 8 weeks after the treatment. But the trend was sustained on week 10, but not significantly different at all experimental group animals housed in SD. Further treatments did not affect gonadal recrudescence at weeks 18 and 23 measured. The results suggest that the GnRH-containing vector might desensitize the anterior pituitary, leading to acceleration f testicular regression but it has no influence on the process of recrudescence.

HPLC를 이용한 내분비 장애물질의 측정

최돈찬 龍仁大學校 1999 용인대학교 논문집 Vol.17 No.-

Endocrine disruptors are the exogenous agents that interfere with the normal processes in the body of living organisms. They affect release, transport, binding, and action of natural hormones, leading to prevent effects of natural hormones in the body responsible for the maintenance of homeostasis and regulation of developmental processes. Their influences are various, including feminization process of males, hermaphrodites in both humans and wildlife, lowered sperm count, testicular and prostate cancer, etc. This study was designed to introduce a method measuring the three endocrine disruptors nonyl phenol, 2-bromopropane, and bisphenol A. HPLC(high performance liquid chromatography) was used with reverse phase Cl8 column. In the present conditions applied, nonyl phenol was detected in the range of 100 ㎍ and 10 mg, 2-bromopropane of 2mg and 200 mg, and a major component of bisphenol A of 10 ㎍ and 10mg and a minor component of bisphenol A of 1 mg and 10mg. Within the dosages used, the minimum amounts detected were 100 palm of nonyl phenol, 2000 ppm of 2-bromopropane, and 10 ppm of a major component of bisphenol A and 1000 ppm of a minor component of bisphenol A. All endocrine disruptors showed dose-dependency, with γ≒1 of linear regression. In a conclusion, three endocrine disruptors nonyl phenol, 2-bromopropane, and bisphenol A are detected and quantified using HPLC.

High Performance Liquid Chromatography를 이용한 멜라토닌 측정

최돈찬,임시내 龍仁大學校 2001 용인대학교 논문집 Vol.19 No.-

Melatonin is a pineal hormone that transduces the photoperiodic information into neuroendocrine system. It acts as a regulator of seasonal reproduction, a biological clock to time circadian rhythmicity, an inhibitor on the growth of tumor and cancer cells, and a controller of cardiovascular function. It also shows anti-aging and life-prolonging effects and a supportive role in the immune system. Melatonin was measured using a conventional HPLC apparatus. Although the sensitivity is low compared to the radioimmunoassay or HPLC with fluorescence or electrochemical detector, these results could be applied to the blood samples withdrawn from the living organisms to which a large amount of melatonin was administered. The method used in this study is simple, convenient, and rapid without need of any further equipments.

컷 골든 햄스터의 생식능력에 미치는 GT 세포의 영향

최돈찬,우대균 용인대학교 자연과학연구소 2003 自然科學硏究所論文誌 Vol.8 No.1

Golden hamsters, whose reproductive activity is active in around summer, are seasonal breeding mammals and their sexual function is controlled by the photoperiod. The levels of gonadotropins secreting from the pituitary are low at winter during which their reproductive functions are regressed, implying that the hypothalamus secrets less amount of gonadotropin releasing hormone (GnRH). Thus whether the reproductive regression induced by the short photoperiod(SP, ≤12 hours of hght in a day) is recovered by the GT cell secreting GnRH implanted into the hypothalamus is investigated. As results, gonadal involution invoked by the exposure to SP was partially overcome by the implants of GT cells. The results indicate that SP affects the hypothalamic GnRH neurons by reducing their release, leading to the gonadal regression The findings of the present study suggest that GT cells increase the levels of GnRH, resulting in suppressing effects of SP.