• 한국환경성돌연변이발암원학회지
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• 제26권2호
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• pp.53-58
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• 2006

Normally, environmental toxicants are classified as endocrine disruptors if they interfere with regulation of cellular function by endogeneous steroids through inhibition of receptor binding and/or transcriptional activation. So, many studies have been performed about agonist/antagonist of hormone receptor to study mechanisms of endocrine disruptors. If toxicants affect steroid biosynthesis and/or degradation and alter hormone homeostasis, these also are classified as endocrine disruptors. But there are not many studies of the mechanisms of endocrine disruptors on the basis of alteration of steroid biosynthesis and/or degradation. Isolation and culture of Leydig cells from testis is one of methods for the steroidogenesis screening assays to evaluate a substance for altering steroidogenesis. Leydig cells were harvested using the method described by Klinefelter with modifications. Leydig cells were purified by perfusion of testis and incubation ($34^{\circ}C$, 80cycles/minute, 20 minutes) with collagenase (0.25 mg/kg), centrifugal elutriation, percoll gradient centrifugation and BSA multidensity gradient centrifugation. To confirm if this method is one of appropriate tools to evaluate a substance for altering steroidogenesis, ketoconazole, positive control was administered to purified Leydig cells. Ketoconazole ($10^{-8}M$ and above) significantly reduced testosterone production in purified Leydig cells. From above results, we suggest that this method for steroidogenesis screening assay appears to be a appropriate tool to detect suspected compounds for altering steroidogenesis.

• 한국수산과학회지
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• 제33권5호
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• pp.403-407
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• 2000

징거미새우의 정소는 간췌장의 배면 측상부에서 심장사이에 위치하며, 한 쌍의 소엽으로 이루어져 있고 각 소엽의 선단은 서로 연결되어 있다. 그리고 각 소엽은 수많은 세정관이 결합조직으로 연결되어 있다. 각 세정관은 생식세포와 지주세포가 밀착되어 있는 생식세포대를 제외한 부분은 낮은 입방상피에 의해 내강이 형성되어 있고, 세정관의 제일 바깥은 단층편평상피로 둘러싸여 있다. 세정관 사이에는 결합조직 외에 Leydig cell-like cell도 관찰된다. 단층편평상피세포는 얇은 측면으로 연결되어 있고 종종 이웃한 세포와 포개져 있다. 지주세포는 생식세포에 비해 그 수가 현저히 적고, 대부분 생식세포대의 가장자리에 위치하고 있다. 지주세포의 세포질은 기저판과 접해 있어 기저면과 생식세포 사이는 지주세포의 원형질에 의해 분리되어 있다. 지주세포의 핵은 대부분 각져 있고, 크고 현저한 인이 핵의 중심부에 위치하고 있다. 낮은 입방상피세포는 세정관의 기저판과 접하고 있는 기저면과 일부는 생식세포대와 내강 사이에 위치하고 있다. 입방상피세포의 세포질에서는 횡 방향의 크리스테가 발달된 미토콘드리아, 층상구조의 조면소포체 그리고 Golgi 복합체들이 매우 발달되어 있다. 그리고 조면소포체와 Golgi 복합체의 볼록한 형성면 사이에는 전이소낭이, Golgi 복합체의 성숙면에서는 분비소낭이 관찰되며, 상피세포의 선단에 수많은 홈들이 존재하는 점으로 보아 exocytosis에 의해 내강으로의 물질 분비가 이루어지는 것으로 판단된다.

• Clinical and Experimental Reproductive Medicine
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• 제31권4호
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• pp.235-244
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• 2004

Objective: The effects on spermatogenesis by expression of vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) were investigated. Materials and Methods: Testicular specimens were obtained from 40 infertile males due to primary testicular failure and from 10 fertile males with other urologic problems. The specimens of infertile males were devided into 4 groups according to histologic findings; Sertoli cell only syndrome (A), maturation arrest (B), hypospermatogenesis (C) and sloughing and disorganization (D). VEGF and ET-1 expression were detected with immunohistochemical stain. Results: VEGF expression on Leydig cell was detected in all cases. But, VEGF expression rates on germ cell were significantly higher in infertile group B, C, D compared to that of the control group (p<0.05). ET-1 expression rates on Leydig cell was significantly lower in all infertile group compared to that of the control group (p<0.05). But, ET-1 expression rates on Sertoli cell was significantly higher in all infertile group compared to that of the control group (p>0.05). In germ cell of infertile group, LH, FSH and prolactin were significantly decreased, and estradiol is increased in positive stain group on ET-1 immunohistochemical stain (p<0.05). VEGF and ET-1 expression were not correlated mean seminiferous tubule diameter (p>0.05). Conclusions: Abnormal spermatogenesis would be reflected in VEGF expression in germ cell.

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2006년도 The 5th Biannual Meeting of Pacific Rim Society for Fertility and Sterility
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• pp.171.1-171.1
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• 2006

• 한국발생생물학회지:발생과생식
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• 제1권2호
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• pp.125-132
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• 1997

To investigate the cadmium (Cd) toxicity on the testis, male rats were treated with 1, 2, 4 and 8 mg/kg of Cd by IP. According to histochemical studies, Cd-treated testis tissue showed death of spermatozoa, death of Sertoli cells, death of all the spermatogenic cells, and finally disappearance of basal lamina of seminiferous tubules with increasing doses, and showed decreased ground substances and Leydig cells, increased inflammatory cells and fibroblasts, and fibroblasts, and finally disappearance of ground substances and all the cells except fibroblasts within interstitial tissues with increasing doses. According to biochemical studies, two kinds of proteins, 25 and 45 kDa, were dramatically disappeared from the total protein of rat testis treated with Cd comparing to normal testis. The result of electrophoresis of total protein suggests that actin (45 kDa), presumed on its mmolecular weight and amount, in the testis-cells is the primary target of Cd poisoning. Although its exact mechanism is not clear, the disappearance of two proteins when testis is exposed to Cd should give some clues to understnad the mechanism of necrosis of testis tissue crumbling by heavy metal pollutant such as Cd.

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2003년도 추계학술대회
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• pp.137-137
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• 2003

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2004년도 KSOT/KEMS Fall Annual Meeting
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• pp.147-147
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• 2004

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2003년도 추계학술대회
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• pp.138-138
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• 2003

• 한국독성학회:학술대회논문집
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• 한국독성학회 2003년도 추계학술대회
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• pp.137-137
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• 2003

Dichlorodiphenyltrichloroethane (DDT) is a widespread environmental pollutant. Earlier reports have demonstrated that DDT is an endocrine-active compound capable of affecting early-stage sexual differentiation in male rats. Experiments based on receptor binding affinity and receptor-mediated transcriptional activation have identified DDE as an androgen receptor antagonist.(omitted)

• Applied Microscopy
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• 제16권2호
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• pp.75-91
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• 1986

Differentiation of the rat testis was studied by light and electron microscope from the fetal stage up to the newborn or adult stage. The purpose of the present study is to investigate the ultrastructural changes of seminiferous tubules and interstitial tissue during the developmental process. The results were as follows: the seminiferous tubule diameter began to increase from birth and was fully developed at 30 to 40 days of age through intratubular cell proliferations. Basement membrane and myoid cells lining the seminiferous tubules were differentiated at 17 days gestation. At the fetal stage, seminiferous tubules were primarily composed of Sertoli cells and the differentiation of Sertoli and germ cells progressed from the newborn stage. Spermatids and immature spermatozoa are appeared at 40 days of age, so from this time, spermatogenesis occurred actively until the adult stage. Sertoli cells aided germ cell differentiation and phagocytosed the parts of the spermatid cytoplasm. Leydig ce]] development follows a biphasic pattern: a fetal phase and then an adult phase from 20 days of age. In conclusion, the rat testis is already developed to some extent by the fetal stage and is functional after 50 days of age. Therefore, these findings indicate that differentiation of Sertoli and Leydig cells precedes the onset of spermatogenesis.