• Korean Journal of Veterinary Research
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• v.42 no.3
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• pp.299-308
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• 2002

The purpose of this morphometric study was to obtain detailed quantitative information on all cell types in the testis interstitium of Korean ring-necked pheasants combined with data on changes in the steroidogenic function of the testis during the breeding and nonbreeding seasons. Animals collected during the breeding season, testis weights, sperm production, serum testosterone levels, leuteinizing hormone-stimulated testosterone secretion, and the length of the seminiferous tubules were significantly (p < 0.05) increased as compared to the nonbreeding season. Seminiferous tubules occupied 93.25% of testis volume in the breeding season. Leydig cells constituted 0.82% of the testicular volume. The mean volume of an Leydig cell was $1039{\mu}m^3$, and each testis contained about 24.53 million Leydig cells. Testes of the pheasants during the nonbreeding season displayed a 98% reduction in testis volume that was associated with a decrease in the absolute volume of seminiferous tubules (98% reduction), tubular lumen(100%), interstitium(90%), blood vessels(84%), lymphatic spaces(97%), Leydig cells(79%), mesenchymal cells(51%), and myoid cells(61%). The number of Leydig cells, mesenchymal cells, myoid cells per testis in the breeding season was higher (p < 0.05) than in the nonbreeding season. Although the average volume of a Leydig cell was 74% lower in the nonbreeding season, the average volume of a myoid and mesenchymal cell remained unchanged. These results demonstrate that there are a striking differences in the testicular structure of the Korean ring-necked pheasant in the breeding and nonbreeding seasons. Every structural parameter of the Leydig cell was pasitively correlated with both serum and LH-stimulated secretion concentrations of testosterone. Correlation of changes in hormonal status with morphometric alterations of all Leydig cell suggests that the Korean-ring necked pheasant may be used as a model to study structure-function relations in the avian testis.

• Development and Reproduction
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• v.7 no.2
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• pp.89-93
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• 2003

The present study observed the ultrastructure of testis of bluespotted mud hopper(Boleophthalmus pectinirostris), and sperrnatogenesis was discussed also. The testis was surrounded by a thin adventitia, inside which spermatocyst composed the parenchyma of testis. Each lobule was enwrapped by many spermatocysts, which were filled with different kinds of spermatogenic cell clusters at the same developmental stage. In the lobule lumen there are large numbers of spermatozoa The thin adventitia(outer wall) of testis was composed of outer epithelium, and the underlying layers, such as collagen fiber layer, and myoid tissue. The myoid tissue elongated into the inside of testis, became the main componentof interstitium between spermatocyst where sperrnatogenesis occurred. In addition interstitial cells containing dense homogeneous nucleus and abundant mitochondria were observed. Spermatogonia contained round nucleus with diffuse chromatin and nucleolus, and dense nuclear bodies surround by mitochondria in cytoplasm. The synaptonemal . complex was observed in primary spermatocytes clearly. Early spermatid presented larger round nucleus composed of granular chromatin, which was located in the center of cytoplasm. The nucleus of mid-spermatid composed of finely granular chromatin lied on one side of spermatid, and abundant mitochondria had migrated another side. A nuclear fossa appeared in the site near mitochondria in late-spermatid, and the centriole was formed in nuclear fossa.

• Korean Journal of Poultry Science
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• v.24 no.3
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• pp.107-116
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• 1997

In order to achieve optimal reproductive performance, reliable morphological and physiological basic data on the reproductive organs are desirable. Adult male Korean ring-necked pheasant in inactive(mid of January) and active state (end of April) were used in this study. In addition, five active state pheasants were received a single dose of 60Co-ray 500 rads each to damage the testes. The objective of this study was to investigate the distribution pattern of protein gene product (PGP) 9.5 and ${\alpha}$-tubulin in the pheasant testes of the active, inactive and ${\gamma}$-ray irradiated active states. The results obtained were summarized as follows 1. The seminiferous tubules collected in inactive states( mid of Jan) showed narrow lumen, and the spermatogonia and the Sertoli cell were well preserved. The PGP 9.5 immunoreactivity of these tubules showed a positive reaction in paranucleus area of the spermatogonia, and a positive reaction in a small number of the Leydig cells in the interstitium of the seminiferous tubules. 2. The seminiferous tubules were dilated in active state(end of April) as compared with the inactive state. The PGP 9.5 reactivity in these tubules showed a positive reaction in many Leydig cells in the interstitium of the seminiferous tubules, and the testes of ${\gamma}$-ray irradiated group showed partially weak reaction in the interstitium of the seminiferous tubules. 3. The ${\alpha}$-tubulin reactivity in the seminiferous tubules of the inactive testes was strongly positive in the cytoplasmic process of the Sertoli cell from the basal stem region to the apical ex-tension. From the broad part of the stem region to the luminal space, the active testes showed a strong positive reaction. The ${\gamma}$-ray irradiated groups showed diminished reaction in the basal region.

• Korean Journal of Veterinary Research
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• v.43 no.4
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• pp.531-539
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• 2003

Changes in the rat testis interstitium from birth to adulthood were studied using Sprague Dawley rats of 1, 7, 14, 21, 28, 40, 60, and 90 days of age to investigate Leydig cell differentiation. In addition, serum testosterone concentrations and luteinizing hormone stimulated (LH; 100 ng/ml) testosterone secretory capacity per testis in vitro were determined via radioimmunoassay. Fetal Leydig cells were present in rat testes from birth to 21 days, and they were only steroidogenic cells in the testis at days 1 and 7. The average volume of a fetal Leydig cell and the absolute volume of fetal Leydig cell per testis were similar at all ages of experimental groups except at day 21 when lower values were observed for both parameters. The number of fetal Leydig cells per testis remained constant from birth through 21 days. Adult Leydig cells were recognized at day 14 and their absolute volume and number per testis increased linearly from 14 to 90 days. The average volume of an adult Leydig cell increased significantly with age and reached maximum size by 60 days of age where the volume was nearly three times bigger than that of at day 14. Total testosterone production per testis in vitro and serum testosterone concentrations were not significantly different at day 1 compared with 7, 14, and 21 days of age. Significant increases were observed at days 40 and 60. Values at days 60 and 90 were not significantly different.

• Korean Journal of Veterinary Research
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• v.43 no.4
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• pp.541-549
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• 2003

The present study investigated the effects of aging on Leydig cells of Sprague Dawley rats. Rats of 3, 6, 12 and 18 months of age were used. Testes of rat were fixed by whole body perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in epon-araldite. Using $1{\mu}m$ sections stained with methylene blue, qualitative and quantitative morphological studies were performed. Testis incubations were used to determine luteinizing hormone (LH; 100 ng/ml) stimulated testosterone secretory capacity per testis in vitro. Testosterone levels in the incubation medium, and testosterone and luteinizing hormone levels in serum of these four groups of rats were determined by radioimmunoassay. Morphological studies revealed that Leydig cells were more abundant in the testis interstitium at 6, 12 and 18 months when compared with 3 months. The volumes of Leydig cells per testis was significantly higher, at 6, 12 and 18 months of age than those at 3 months. The number of Leydig cells per testis was doubled at 6, 12 and 18 months of age compared with 3 months. The average volume of a Leydig cell was not significantly different between 3 and 6 months of age, however, at 12 and 18 months a significantly lower value was observed. LH-stimulated testosterone production per testis in vitro was reduced by 45% at 6 months of age compared with 3 months; a further significant reduction was observed at 12 and 18 months. Serum testosterone and LH levels were not significantly different between 3 and 6 months of age but at 12 and 18 months a significantly lower value was observed in both groups for these hormones. These results showed that signs of aging are apparent in Leydig cells of Sprague Dawley rats at 12 months of age.

• Korean Journal of Veterinary Research
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• v.45 no.3
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• pp.325-334
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• 2005

Changes in the rabbit Leydig cell from birth to adulthood were studied in New Zealand white rabbits of 1, 7, 21, 35, 49, 70, 105, 147, 196, and 252 days (n = 8 rabbits per group) of age. The objectives of this study were to understand the fate of the fetal Leydig cells, to determine the changes in serum testosterone levels, and leutenizing hormone-stimulated testosterone production per testis in vitro, and to quantify adult Leydig cells by number and average volume with age. Testes of rabbits were fixed by whole body perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using $1{\mu}m$ sections stained with methylene blue-azure II, qualitative and quantitative (stereological) morphological studies were performed. Testosterone levels in the incubation medium of luteinizing hormone-stimulated (100 ng/ml) testosterone secretion per testis in vitro, and in serum were determined by radioimmunoassay. The average volume of a testis of 1-day-old rabbits was determined as $0.0073cm^3$ and the parameter increased linearly from birth to 252 days ($3.93cm^3$). The volume density of the seminiferous tubules increased with age from 33.76% at day 1 to 88.2% at day 252. The volume density of the interstitium represents 66.24% of the testicular parenchyma at day 1. This proportion progressively diminished during development to reach a value of 11.8% at day 252. The volume density of Leydig cells increased almost linearly from birth (0.001%) to 252 days (2.62%). Leydig cell mass per testis increases from 0.0012 mg to 0.25 mg between days 1 and 35, from 2.66 mg to 44.3 mg between days 49 and 105 and from 65.42 mg and 102.9 mg between days 147 and 252. The absolute numbers of adult Leydig cells per testis increased linearly from birth to 252 days. The average volume of adult Leydig cell on days 1, 7, 21 and 35 was not significantly different; a gradual and continued increase was observed thereafter, reaching a 3-fold increase at 196 and 252 days. Serum testosterone concentrations were not significantly different at day 1 compared days 7, 21, 35. Significant increases were observed at days 49 and 70. Values at days 70 and 105 and days 147, 196, and 252 were not significantly different. LH-stimulated testosterone production per testis in vitro was significantly different at day 1 compared days 7, 21, 35. Significant increases were observed at days 49 and 70. Hormonal values at days 105, 147, 196, and 252 were not significantly different. These data suggested Leydig cell developmental phase can be classified: a neonatal phase (1-7 days), a prepubertal phase (14-49 days) and an adult phase (70-252 days). Immature and mature adult Leydig cells, initially detected at days 7 and 49, respectively, and mature adult Leydig cells were abundant Leydig cell type according to the number and absolute volume per testis form day 49 onwards.

• Korean Journal of Poultry Science
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• v.32 no.2
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• pp.125-133
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• 2005

Morphometric changes in testicular Sertoli and Leydig cells from hatching to adulthood were studied using Korean native chickens of 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 21, 24, 28, 32, 44, 52 and 64 weeks (n=13 chickens per group) of age. The objective of this study was to understand the developmental phase of the Sertoli and Leydig cells with age. Testis of chickens was fixed by whole body perfusion using a fixative containing $2.5\%$ glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using 1 Um sections stained with methylene blue-azure II, qualitative and quantitative (stereological) morphological studies were performed. The average volume of a testis of 1 week old Korean native chickens was determined as $0.148\;cm^3$ and the parameter increased linearly from 1 week to 21 weeks days $(28.86\;cm^3)$, and did not change from 21 weeks to 64 weeks. The volume density of the seminiferous tubules increased with age from $32.6\%$ at week 1 to $92.89\%$ at week 64. The volume density of the interstitium represents $67.4\%$ of the testicular parenchyma at week 1. This proportion progressively diminished during development to reach a value of $7.11\%$ at week 64. The volume density of the Leydig cells decreased almost linearly from 1 week $(4.9\%)$ to 14 weeks $(1.7\%)$ and remained unchanged thereafter. In contrast, the Sertoli cells occupied a volume density of $3.4\%$ at week 1, increased progressively up to 18 weeks of age $(10.79\%)$ and remained unchanged thereafter. The absolute volume of the Leydig and Sertoli cells per testis increased significantly from week 1 to week 21 but did not change significantly from week 24 to week 64. The number of Leydig cells per testis increased almost linearly from 1 week to 21 weeks, remained high and unchanged with advancing age. The number of Sertoli cells per testis increased gradually with age from 1 week to 14 weeks and remained unchanged thereafter.

• Korean Journal of Veterinary Service
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• v.39 no.3
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• pp.141-149
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• 2016

Changes in the Leydig cell from pre-puberty to adulthood were studied in Korean native cattle. Eight groups of male cattle aged 14, 17, 20, 25, 30, 35, 40 and 104 weeks (n=7 cattle per group) after birth were used. The purpose of this study was to obtain quantitative information on the Leydig cell of the Korean native cattle during postnatal development. Testes of cattle were fixed by perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using $1{\mu}m$ section stained with methylene blue-azure II, qualitative and quantitative (stereological) morphological studies were performed. The average diameter of seminiferous tubules gradually increased with age from 14 ($75.56{\mu}m$) to 104 weeks ($298.9{\mu}m$). The volume density of the seminiferous tubules increased with age from 54.2% at week 14 to 76.9% at week 104. The volume density of the interstitium represents 45.52% at week 14. This proportion progressively diminishes during development to reach a value of 23.14% at week 104. The volume density of Leydig cells decreased almost linearly from 14 (20.71%) to 104 weeks (5.28%). The absolute volume of Leydig cells per testis increased significantly from 14 to 104 weeks. The number of Leydig per testis have almost linearly increased from 14 to 104 weeks. The average volume of a Leydig cell reached maximum size by 104 weeks ($2553{\mu}m^3$). These data suggested development of Leydig cell can be classified as the fetal and immature adult Leydig cells (14~35 weeks), and the adult Leydig cells (40~104 weeks).

• Korean Journal of Poultry Science
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• v.33 no.3
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• pp.171-179
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• 2006

Changes in the chicken testis from hatching to adulthood were studied in Korean native chickens of 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 21, 24, 28, 32, 44, 52 and 64 weeks (n=13 chickens per group) of age. The present study was to investigate in more detail the post-hatching development of testis in Korean native chickens. Testes of chickens were fixed by whole body perfusion using a fixative containing 2.5% glutaraldehyde in cacodylate buffer, processed and embedded in Epon-araldite. Using $1{\mu}m$ sections stained with methylene blue-azure II, qualitative and quantitative(stereological) morphological studies were performed. Sperm production was measured by routine technique. The average volume of a testis of 1 week old Korean native chickens was determined as 0.015 g and the parameter increased linearly from 1 week to 21 weeks days (28.9 g), and did not change from 21 weeks to 64 weeks. The volume density of the seminiferous tubules increased with age from 32.6% at week 1 to 92.89% at week 64. The volume density of the interstitium represents 67.4% of the testicular parenchyma at week 1. This proportion progressively diminished during development to reach a value of 7.11% at week 64. Total sperm production per testis increased significantly from 18 weeks to 28 weeks and remained unchanged. Sperm production per 1 g testis increased significantly from 18 weeks to 28 weeks, did not change significantly from 28 weeks to 52 weeks, and declined significantly at 64 weeks of age. The average diameter of the seminiferous tubules gradually increased with age from 1 week $(42.4{\mu}m)$ to 21 weeks $(412.8{\mu}m)$. The length of the seminiferous tubules was 0.34 m at 1 week, increased significantly in subsequent age groups and reached 72.2 m by weeks 64. The stage of germ cell development in seminiferous tubules was classified as 1) spermatogonia $(1\sim8\;weeks)$, 2) spermatogonia and spermatocytes $(10\sim12\;weeks)$, 3) spermatogonia, spermatocytes and round spermatids $(14\sim16\;weeks)$, and 4) speramatogonia, spermatocytes, spermatids and spermatozoa $(18\sim64\;weeks)$. These results clarified the pattern of changes in the testicular development in Korean native chickens from hatching to adulthood as 1) neonatal-prepubertal $(1\sim12\;weeks)$, 2) puberty$(14\sim18\;weeks)$, and adult$(21\sim64\;weeks)$.

• Applied Microscopy
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• v.29 no.4
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• pp.511-522
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• 1999

The Leydig cell found within the interstitium of the testis is important in the spermatogenesis. The differentiation of Leydig cell, even though relatively well known in animals, is not fully elucidated yet in human. In the present study, human fetal testes ($14\sim27$ weeks) obtained from artificially induced abortions legally without gross malformations were studied using light and transmission electron microscopy to make clear the differentiation process of Leydig cells in humans. Leydig cells could be classified as 4 types: fusiform, light, dark, and degenerating cells. The most immature cell was the fusiform cells found frequently at 14 weeks, which seemed to differentiate successively into light and dark cells. Light cells were most frequently found at 17 weeks and dark cells at 24 weeks. Light cells were found to have mitochondria and smooth endoplasmic reticuli (sER) most prominently than any other cell types. The lumen of sER became to be expanded with age. Some electron-dense inclusions were observed in the mitochondrial matrix of the dark cells. Lipid droplets found more in light cells than dark cells were most prominent at 16 weeks and gradually decreased after 20 weeks. Glycogen particles were rich in dark cells. Degenerating cells were most frequently found at 27 weeks. From the results, it is suggested that Leydig cells in human fetal testes undergo similar differentiation process af in animals.