• Asian-Australasian Journal of Animal Sciences
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• v.24 no.8
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• pp.1060-1068
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• 2011

The LDH isozymes are key catalysts in the glycolytic pathway of energy metabolism. It is well known that the distribution of the LDH isozymes vary in accordance with the metabolic requirements of different tissues. The substrates required for energy production change noticeably at successive stages of testes development suggesting a significant flexibility in the expression of glycolytic enzymes. Therefore, expression of LHDA and LDHB mRNAs was examined in adult and prepubertal quail testis. The mRNA of both LDHA and LDHB were expressed and no significant difference was observed in prepubertal testes. The mRNA levels of LDHB significantly increased during testicular development. In the adult testis, LDHA mRNA was not expressed. Expression studies revealed the presence of different LDH isozymes during testicular development. In contrast, electrophoresis of both testicular samples revealed only single band at a position indicative of an extreme type of LDH isozyme in quail testes. Furthermore, nucleotide and amino acid sequence analysis revealed significant similarity to chicken, duck and rock pigeon. These sequence results confirmed the similarity of LDHA and LDHB subunit protein in different avian species.

• Development and Reproduction
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• v.25 no.1
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• pp.1-14
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• 2021

The Syrian (golden) hamsters are seasonal breeders whose reproductive functions are active in summer and inactive in winter. In experimental facility mimicking winter climate, short photoperiod (SP) induces gonadal regression. The blood-testis barrier (BTB) of the sexually involuted animals have been reported to be permeable, allowing developing germ cells to be engulfed or sloughed off the epithelium of the seminiferous tubules. The expressions of genes related to the tight junction composing of BTB were investigated in the reproductive active and inactive testes. Claudin-11, occludin, and junctional adhesion molecule (JAM) were definitely expressed in the active testes but not discernably detected in the inactive testes. And spermatozoa (sperm) were observed in the whole lengths of epididymides in the active testes. They were witnessed in only cauda region of the epididymides but not in caput and corpus regions in animals with the inactive testes. The results imply that the disorganization of BTB is associated with the testicular regression. The developing germ cells are swallowed into the Sertoli cells or travel into the lumen, as supported by the presence of the sperm delayed in the last region of the epididymis. These outcomes suggest that both apoptosis and desquamation are the processes that eliminate the germ cells during the regressing stage in the Syrian hamsters.

• Development and Reproduction
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• v.26 no.2
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• pp.59-69
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• 2022

Many efforts have been made to study the expression of aquaporins (AQP) in the mammalian reproductive system, but there are not enough data available regarding their localized expression to fully understand their specific roles in male reproduction. The present study investigated the expression and localization patterns of different AQP subtypes in the adult mouse testes and testicular spermatozoa using an immunofluorescence assay. All the studied AQPs were expressed in the testes and revealed subtype-specific patterns in the intensity and localization depending on the cell types of the testes. AQP7 was the most abundant and intensive AQP subtype in the seminiferous tubules, expressing in Leydig cells and Sertoli cells as well as all stages of germ cells, especially the spermatids and testicular spermatozoa. The expression pattern of AQP3 was similar to that of AQP7, but with higher expression in the basal and lower adluminal compartments rather than the upper adluminalcompartment. AQP8 expression was limited to the spermatogonia and Leydig cells whereas AQP9 expression was exclusive to tails of the testicular spermatozoa and elongated spermatids. Taken together, the abundance and distribution of the AQPs across the different cell types in the testes indicating to their relavance in spermatogenesis, as well as in sperm maturation, transition, and function.

• Journal of Animal Reproduction and Biotechnology
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• v.39 no.3
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• pp.194-200
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• 2024

Background: Brain-derived neurotrophic factor (BDNF) and its receptor, neurotrophic tyrosine receptor kinase-2 (NTRK2), are well known for their roles in the central nervous and animal reproductive systems. Several studies have observed the extensive expression of BDNF and NTRK2 in non-neuronal tissues, especially reproductive organs. However, most of these studies focused on ovarian development and regulation; thus, scientific research on BDNF and NTRK2 in males is required to determine their roles in the male reproductive system. Therefore, this study aimed to investigate BDNF and NTRK2 expression in bovine testes. Methods: Testes were collected from six Hanwoo bulls (6-8 months old). Reverse transcription-polymerase chain reaction (RT-PCR) analysis was performed to investigate the mRNA expression of BDNF and NTRK2 in the testes. Western blot analysis was performed to verify the cross-reactivity of BDNF and NTRK2 antibodies with bovine testicular tissues. Immunohistochemistry was conducted to determine BDNF and NTRK2 protein expression in the testes. Results: RT-PCR analysis revealed BDNF and NTRK2 mRNA expression in bovine testes. In Western blotting, BDNF and NTRK2 protein bands were observed at 32 and 45 kDa, respectively. Immunofluorescence demonstrated BDNF expression in the nuclei of spermatogonia and Sertoli cells as well as in the cytoplasm of Leydig cells. NTRK2 was exclusively expressed in Sertoli cells. These results suggest that BDNF plays a potential role in spermatogenesis via BDNF and NTRK2 signaling in bovine testes, a finding supported by previous results in different animal species. Conclusions: The expression patterns of BDNF and NTRK2 indicate their functional importance in the bovine reproductive system.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.12
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• pp.1832-1842
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• 2007

Cytochrome P450 aromatase is responsible for the biosynthesis of estrogen. It is also responsible for the endogenous production of 19-nortestosterone (nandrolone), an anabolic androgen unique to pigs. Plasma concentrations of 19-nortestosterone are highest between two and four weeks after birth in male pigs. In the present study, the physiology of 19-nortestosterone was investigated by measuring the mRNA levels of steroidogenic enzymes, estrogen receptors and androgen receptor in the tissues of growing pigs. The expression of aromatase, 17${\alpha}$-hydroxylase and 3${\beta}$-hydroxysteroid dehydrogenase in the testes of male piglets increased between birth and two weeks of age, and then decreased progressively. Similar developmental expressional patterns were observed for 17${\alpha}$-hydroxylase and 3${\beta}$-hydroxysteroid dehydrogenase in the ovaries of female piglets, but without significant aromatase expression. The major form of aromatase expressed in the testes of piglets was identified as type I. Expression of estrogen receptor-${\alpha}$ and -${\beta}$and androgen receptor genes was also detected in both testes and ovaries. A transient elevation of androgen receptor mRNA in male piglets at two weeks of age was also observed in testes. Significant expression of the androgen receptor gene, but not of estrogen receptor-${\alpha}$ and -${\beta}$ genes, was also demonstrated in adipose tissue and muscle. We conclude that the observed increase in the testicular expression of aromatase in male pigs could account for the production of large amounts of 19-nortestosterone at between two and four weeks of age in males. Androgen receptor and 19-nortestosterone appeared to be important for testicular development and might contribute to sexual dimorphism in body composition and muscle development in juvenile pigs.

• Molecules and Cells
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• v.26 no.6
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• pp.621-624
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• 2008

We previously showed that Asb-4 and Asb-17 is uniquely expressed in developing male germ cells. A recent report showed that Asb-9 is specifically expressed in the kidney and testes; however, detailed expression patterns in developing germ cells have not been shown. Northern blot analysis in various tissues demonstrated that mAsb-9 was strongly expressed in the testes. Expression analysis by RT-PCR and Northern blot in developing mouse testes indicates that mAsb-9 is expressed from the fourth week after birth to adulthood, with the highest expression in round spermatids. Expression sites were further localized by in situ hybridization in the testes. Pachytene spermatocytes and spermatids expressed mAsb-9 but spermatogonia and generated spermatozoa did not. This study reveals that mAsb-9 could be a specific marker of active spermatogenesis and would be useful for studies of male germ cell development.

• Development and Reproduction
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• v.23 no.2
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• pp.101-110
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• 2019

Melatonin is a pineal hormone that is synthesized and released at night under the light and dark cycles of a day. Its effects on the reproductive activities have well been established by the administration through various routes in photoperiodic animals. It was also identified in plants and named phytomelatonin. The capacity of the phytomelatonin was investigated in this investigation whether it affects the reproductive function in male golden hamster. As expected, animals housed in long photoperiod (long photoperiod, LP>12.5 hours of lights in a day) had large testes and animals kept in short photoperiod ($$SP{\leq_-}12.5$$ hours of lights in a day) showed remarkably reduced testes. The dietary supplement with melatonin itself induced the complete involution of testes. Pistachios that were reported to contain a large amount of melatonin demonstrated no effects at all in male golden hamsters. These results suggest that dietary supplement containing melatonin-rich foodstuff used in this investigation may not be enough to affect the reproductive endocrine system in male golden hamsters.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.109-109
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• 2002

In recent reports, the multiple reproductive defects such as cryptorchidism, hypospadias, epididymal cysts, low sperm counts, and testicular cancers are increased in humans, and these changes were doubted by the chemicals with estrogenic or antiandrogenic activities in our environment. To compare the effects of neonatal exposure of di (n-butyl) phthalate and flutamide on the development of reproductive organs and to identify the specific mechanisms of these abnormalities related to the male reproducton, Sprague-Dawley neonate male rats were injected subcutaneously during 5-14 days after birth with corn oil (control), flutamide (0.05, 0.1, and 0.5 mg/animal) and DBP (5, 10, and 20 mg/animal). Animals were killed at 31 (immature) and 42 (pubertal) days of age respectively and blood was collected from abdominal aorta for serum testosterone analysis. Testes, epididymides, seminal vesicles, ventral prostate, levator ani plus bulbocavernosus muscle (LABC), cowpers glands and glans penis were weighed. Expression of steroid hormone receptors (AR and ER) was examined in the testes and ventral prostate. At 31 days of age, ventral prostate, seminal vesicles, LABC, and cowpers glands significantly decreased in the flutamide (0.5 mg/animal) and DBP (20 mg/animal), but serum testosterone levels were not changed. Flutamide slightly delayed the testes descent at the high dose (0.5 mg/animal), but DBP did not show any significant effect on the testes descent at all doses. DBP and flutamide decreased the expression of AR protein in the testes but did not affect the expression of ERa and ER protein in the testes. At 42 days of age, ventral prostate, seminal vesicles, and cowpers glands weights were still significantly decreased at the high dose of flutamide (0.5 mg/animal) and DBP (20 mg/animal), but the weights of testes and epididymides were not different. Serum testosterone decreased significantly in DBP treated animals and slightly, not significantly, in flutamide group. While DBP still significantly decreased the expression of AR protein in testis, flutamide recovered from downregulation of AR protein and did not affect the expression of ERa and ER protein in the testes. Based on these results, flutamide and DBP have shown several similar patterns in reproductive abnormalitis, but some marked differences which may be caused by different acting mechanism.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.417-424
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• 1989

This study was conducted in order to observe the changes in cellular association of seminiferous tubules from 4 to 22 weeks of age and to obtain the cycle and relative duration of seminiferous epithelia from 24 weeks of age in male ducks. Fifety-five male ducks were used in the experiment and divided into 11 groups, consisting of 5 male ducks each, with 2 weeks intervals from 4 to 24 weeks of age. The results were summarized as follows: 1. The body and testes weight showed most rapid increase during 4 to 6 weeks and 18 to 22 weeks of age, respectively. The seminiferous tubules were obruptly enlarged in diameter of tubules during 18 to 22 weeks of age. 2. Gonocytes were seen from 4 to 6 weeks of age, however they were not observed as from 8 weeks of age. Both type Ap spermatogonia and type Ad spermatogonia occured from 8 to 12 weeks of age, while spermatocytes and spermatids were beginning to appear at 16 weeks and 18 weeks of age, respectively. Spermatozoa were first observed at 20 weeks of age. Full spermatogenic activity was completed at the age of 20 weeks. 3. Average paired weight of the testes in male ducks was 78g at 24 weeks of age and its ratio to the body weight was approximately 2.5 percent. 4. Average diameter of seminiferous epithelium at 22 weeks of age was $232{\mu}m$, and average numbers of Sertoli cell, spermatogonia, spermatocyte, spermatids and spermatozoa in the cross section of seminiferous epithelium were 15.30, 59.08, 41.78, 71.11 and 165.30, respectively. Spermatogonia and spermatids were classified into 2 and 4 types, respectively. 5. The cycle of the seminiferous epithelium could be divided into 5 stages at 24 weeks of age. The relative frequencies of stages from I to V were 13.5%, 25.0%, 22.3%, 20.6% and 18.7% respectively. Thus, establishment of spermatogenesis in male ducks were beginning to appear at 20 weeks of age.

• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.229-236
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• 2000

The synthesis of steroid hormone starts from cholesterol. Steroidogenic acute regulatory protein (StAR) acutely transfers cholesterol from the outer mitochondrial membrane to the inner in the early step of steroidogenesis. Many kinds of steroid hormone are mainly synthesized in adrenal grand, ovary, and testis. Among the steroid hormone, testosterone is synthesized in Leydig cells of the testis, the production of testosterone significantly increases in adult testis after puberty onset. Therefore, we think that the expression of StAR mRNA in testis will change according to the testicular development. The aim of this study is to determine the distribution of StAR mRNA in immature and adult rat testes and to confirm the functions of StAR in these testes. Thus, in situ hybridization was used in rat testes of the 2, 4, and 10 weeks of age. StAR mRNA was expressed in Leydig cells. Positive signals of StAR mRNA were weakly detected in Leydig cells of the 2 weeks of age. But, StAR mRNA was strongly expressed in Leydig cells of the 4 and 10 weeks of age, where steroidogenesis actively occur. In our results, the pattern of StAR mRNA expression was similar to the pattern of testosterone production in immature and adult rat testes. In conclusion, we can suggest that StAR acts as an important factor to regulate the synthesis of testosterone in Leydig cells of the rat testis.