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.

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.

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 용인대학교 2001 용인대학교 논문집 Vol.19 No.-

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.

A Limit Cycle Model about the Entrainment of Circadian Rhythm

최돈찬 한국발생생물학회 2008 발생과 생식 Vol.12 No.1

현존하는 생물들은 주변 환경에서 오는 반복되는 신호의 영향을 받고 있다. 그 신호는 태양 및 지구의 운동 관계에서 되풀이되어 일어나는 주기적인 변화이다. 생식 및 번식, 세포 내 각종 분자들의 작용, 발생 단계에 일어나는 다양한 변화 등등의 생리학적/행동학적 활동들은 모두 일주기든 연주기든 주기성을 띠고 있다. 일주기 리듬을 통하여 생물들은 근본적으로 주변의 외부 시간에 그 생물 자체가 적응하게 하여, 일상적으로 반복되는 환경에서 적절한 시기에 활동하도 All the organisms on the earth are affected by the repeating signals from the ambient environment caused by the movements of the sun and the earth. Their physiological and behavioral activities such as reproduction, functional pathway of various molecules, and developmental stage, are reflected by the cyclicity whether it is daily(circadian) or annual rhythms. An essential function of circadian rhythms is to provide an internal estimate of the external local time, thereby allowing the organism to program its activities so that they occur at an appropriate time in the daily environment. Of many rhythmic patterns, the circadian rhythms are considered in this review, focusing on the limit cycle, which is a model to investigate the entrainment.

Effects of Acetaminophen on Reproductive Activities in Male Golden Hamsters

최돈찬,이채연,황현지,박진수,이성호,박창은,전용필 한국발생생물학회 2023 발생과 생식 Vol.27 No.1

Acetaminophen [Paracetamol, N-acetyl-para-aminophenol (APAP)] is a common over-thecounter analgesic agent as nonsteroidal anti-inflammatory drugs (NSAIDs). The high doses or the long-term treatment of acetaminophen via usual gavage feeding resulted in damage of testicles that presented recoverable impairment, as well as liver and kidney. The influence of acetaminophen was examined in male golden hamsters treated with acetaminophencontaining diet feeding. They were divided into 5 groups and subjected to this experiment for 4 weeks: animals housed in long photoperiod (LP) as LP control, animals housed in short photoperiod (SP) for 4 weeks as SP control (SP4), and groups of animals treated with low, middle, and high concentrations of acetaminophen (Low, Middle, High groups). Also animals housed in SP for 8 weeks were included (SP8) to contrast testicular activities, if necessary. As results, spermatozoa filled the seminiferous tubules of the testicles of animals in LP control and SP4 groups. The aspects were seen in the animals taken diets of low and middle doses of acetaminophen. The animals who fed high dose of acetaminophen showed large or small testicles. The large testicles displayed all germ cells at the steps of spermatogenesis. The small testicles presented no sperm as the animals housed in SP for 8 weeks. Thus these results indicate that acetaminophen invokes the antigonadal effects and accelerates the regressing process of the testicles in the animals compared to the animals exposed to SP.

수컷 골든 햄스터에서 광주기에 따른 Gonadotropin Releasing Hormone 유전자 발현

최돈찬,박창은,최형재 용인대학교 자연과학연구소 2000 自然科學硏究所論文誌 Vol.5 No.1

The sexual activity of golden hamsters is controlled by photoperiod(light/day), being active in summer and inactive in winter. Adult hamsters in a short day(SD, ≤12 hours of light/day) show gonadal regression at about 8 week regardless of sex. The regressed testes display remarkably lowered follicle-stimulating hormone and luteinizing hormone levels in blood. The synthesis and release of gonadotropins are well established to be regulated by the gonadotropin releasing hormone(GnRH). Thus, it is thought that SD curtails the release of GnRH. Removal of pineal gland always sustains the sexual activity. A proper treatment of melatonin, a major hormone secreting from the pineal gland, suppresses the sexual function, indicating the mediation by melatonin. Thus the expression of GnRH gene was examined in the hypothalamus depending on photoperiods in male golden hamsters. As results, GnRH gene was partially identified and detected concurrently in the preoptic area and mediobasal hypothalamus. Thus, photoperiod appeared not to affect the expression of GnRH gene. But the effects of SD was blocked by the removal of pineal gland. These results suggest that photoperiod and pineal gland do not affect the experession of GnRH gene but may affect the releasing mechanism of GnRH from hypothalamus of male golden hamsters.

HPLC를 이용한 내분비 장애물질의 측정

최돈찬 용인대학교 1999 용인대학교 논문집 Vol.17 No.-