• Environmental Mutagens and Carcinogens
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• v.26 no.2
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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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.403-407
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• 2000

Ultrastructure and function of testis somatic cells in freshwater prawns Macrobrachium nipponense were studied. The paired testes of the prawn were elongated, united at their anterior end, which lay between the dorsal surface of the hepatopancreas and the heart. Each testis consisted of a large number of seminiferous cords compactly held together by connective tissue. A seminiferous cord was composed of an outer layer of simple squamous epithelium, a basement membrane, the closely packed germ cells and sustentacular cells of the germinal ridge, and an inner layer of simple cuboidal epithelial cells. Leydig cell-like cells in an angular areas filling the space of the seminiferous cords were observed. The nuclei of leydig cell-like cells were characterized by a distinct nucleolus. The simple squamous epithelial layer was composed of flattened cells tying on a basement membrane. The nuclei of the flattened cells were often overlapped in a layer, and the cytoplasm of the cells was observed just near the nuclei. The sustentacular cells were complex in morphology. These cells had relatively small cell bodies from which long cytoplasmic extensions ramified reached the space of germ cells in the germinal ridge. The nuclei of sustentacular cells usually exhibited angular profiles and located most commonly at the periphery of the cords. Cells of simple cuboidal epithelium located between germinal ridge and lumen of seminiferous cord, and part of the cells were adjacent to basal lamina, The cuboidal epithelial cells contained numerous mitochondria, the well-developed rER, the well-developed Golgi complex, and irregularly shaped nuclei. Transition vesicles appeared on the cis side of the Golgi complex. The large vesicles on the trans side of the complex appeared to fuse to form a membrane-bound structure. A number of pits on the cell apex suggested exocytotic activity for secretion of the sperm supporting matrix.

• Clinical and Experimental Reproductive Medicine
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• v.31 no.4
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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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• 2006.06a
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• pp.171.1-171.1
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• 2006

• Development and Reproduction
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• v.1 no.2
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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.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.10a
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• pp.137-137
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• 2003

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.11a
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• pp.147-147
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• 2004

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2003.10a
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• pp.138-138
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• 2003

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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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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• v.16 no.2
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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.