• Molecules and Cells
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• v.42 no.2
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• pp.97-103
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• 2019

Androgens act in almost all tissues throughout the lifetime and have important roles in skeletal muscles. The levels of androgens increase during puberty and remain sustained at high levels in adulthood. Because androgens have an anabolic effect on skeletal muscles and muscle stem cells, these increased levels of androgens after puberty should lead to spontaneous muscle hypertrophy and hyperplasia in adulthood. However, the maintenance of muscle volume, myonuclei number per myofiber, and quiescent state of satellite cells in adulthood despite the high levels of androgens produces paradoxical outcomes. Our recent study revealed that the physiological increase of androgens at puberty initiates the transition of muscle stem cells from proliferation to quiescence by the androgen-Mindbomb1-Notch signaling axis. This newly discovered androgen action on skeletal muscles underscores the physiological importance of androgens on muscle homeostasis throughout life. This review will provide an overview of the new androgen action on skeletal muscles and discuss the paradoxical effects of androgens suggested in previous studies.

• Korean Journal of Animal Reproduction
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• v.20 no.3
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• pp.259-269
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• 1996

To establish whether or not androgens is responsible for the induction of vitellogenin(Vg) synthesis and secretion, primary hepatocytes prepared from immature eels were used. The results are follows: 1. Eel hepatocytes were prepared using a collagenase perfusion technique. The isolated cells attached efficiently to fibronectin-coated dishes and subsequently formed monolayers in serum-free medium. These cultures maintained in medium for 10 days with minimal cell loss. 2. Estradiol-17$\beta$(E2) alone was insufficient to induce Vg synthesis. The combination of E2 with methyltestosterone(MT) markedly stimulated Vg synthesis. High vg production occurred in MT concentration from 10-6~10-5M in the presence of E2 (10-6M). Testosterone and androsterone were also effective, but progesterone was not effective in inducing Vg synthesis. Neither MT alone nor testosterone and androsterone alone had any effect on Vg synthesis. 3. E2-primed hepatocytes showed Vg synthesis in both media with and without hormones 1 day after culture. In the cultures with the vehicle, MT, or progesterone, the rate of synthesis seemed to decrease with time. But the combination of E2 and MT showed an intense increase in Vg synthesis. Hepatocytes isolated from E2-primed eels also required androgens for continuating of Vg synthesis. 4. These results demonstrate that androgens act together with E2 in synthesis and secretion of eel Vg.

• Mass Spectrometry Letters
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• v.1 no.1
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• pp.29-32
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• 2010

Cross reacting antibodies can cause an overestimation of the results of immunoassays. Therefore, alternative methods are needed for the accurate quantification of steroids. Gas chromatography combined with isotope-dilution mass spectrometry (GC-IDMS) is developed to quantify urinary active androgens, testosterone, epitestosterone and dihydrotestosterone, which are clinically relevant androgens to both hair-loss and prostate diseases. The method devised involves enzymatic hydrolysis with $\beta$-glucuronidase, solid-phase extraction, liquid-liquid extraction using methyl tert-butyl ether and subsequent conversion to pentafluorophenyldimethylsilyl-trimethylsilyl (flophemesyl-TMS) derivatives for sensitive and selective analysis in selected-ion monitoring mode. Flophemesyl-TMS derivatization not only eliminates matrix interference but also has a good peak resolution within a 6 min-run. A selective and sensitive GC technique with flophemesyl-TMS derivatives also allows accurate quantitative analysis of three active androgens when combined with IDMS. The limit of quantification of the three analytes was <50 pg/mL, and extraction recoveries ranged from 91.9 to 102.1%. The precision and accuracy were 1.2~6.5% and 89.0~106.7%, respectively. This GC-IDMS method can be useful for evaluating the drug efficacy and monitoring the biological processes responsible for male-pattern baldness and prostate diseases.

• Journal of Aquaculture
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• v.13 no.1
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• pp.79-85
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• 2000

The effects of estrogen and androgens on Vg gene expression were examined in primary hepatocyte culture and livers of the immature male trout. Specific primers of Vg cDNA were designed with already reported Vg gene nucleotide sequences. PCR product was sequenced and verified with Vg cDNA of rainbow trout. Total RNA was extracted from the cultured hepatocytes and livers of steroid-treated rainbow trout and then it was analyzed by reverse transcriptase- polymerase chain reaction (RT-PCR) analysis. The Vg mRNA and Vg protein synthesis were increased in rainbow trout in vivo and in vitro with E$_2$ and methyltestosterone (MT) There were dose and time-related effects of E$_2$ and MT on vitellogesis. Androgens such as progesterone androsterone and testosterone also stimulated Vg mRNA expression in vitro. The results show that androgens as well as E$_2$ can induce expression of Vg mRNA in trout in vivo and in vitro.

• Journal of Ginseng Research
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• v.9 no.2
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• pp.213-220
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• 1985

It was attempted to observe the effects of ginseng saponin, one of the major components of the roots of Panax ginseng, on androgen biosynthesis from cholesterol in vitro as well as in vivo in rat testis. Ginseng saponin was administered by stomach tubing prior to intraperitoneal injection of cholesterol containing (4-14C)-cholesteroll into adult male rats and the liver, testis and blood serum were analyzed. The first high radioactivity of the liver and blood serum of test animal was observed at 6 hours after radioactive cholesterol injection, while that of control appeared at 12 hours after the injection. In the case of testis, the first high radioactivity of test group appeared between 4 and 6 hours after the radioactive cholesterol injection, while that of control appeared at 10-14 hours. Analysis of radioactivity distribution of cholesterol, androstenedione and testosterone in the testis of rats fed with/without ginseng saponin piror to (4-14C)-cholesterol injection showed that the saponin stmulated the synthesis of androgens from cholesterol. This was confirmed again by in vitro experiment using testis homogenate as an enzyme source. From the above experimental results, it was suggested that the ginseng saponin stimulates both cholesterol transport and the biosynthesis of androgens from cholesterol in rat testis.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1995.06a
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• pp.159-164
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• 1995

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.145-150
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• 2001

• Proceedings of the PSK Conference
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• 2002.04a
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• pp.226.2-226.2
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• 2002

• Korean Journal of Veterinary Research
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• v.35 no.2
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• pp.263-270
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• 1995

Creatine(Cr) and phosphocreatine(PCr), the important mediators of intracellular high-energy phosphate buffer system, were found in the tissues of mouse seminal vesicle and also in the extracellular fluids of seminal vesicle secretion. This study was performed m confirm that the secretion and accumulation of Cr and PCr is regulated by testosterone and its $5{\alpha}$-reduced metabolite, $5{\alpha}$-dihydrotestosterone(DHT). In addition, the effect of nandrolone decanoate(ND), a synthetic anabolic steroid, on the levels of Cr and PCr in the seminal vesicle was compared with those of testosterone propionate(TP) and DHT. Male Swiss-Webster mice were castrated and three groups of the castrates were treated with daily injection(sc) of same molar dose($1.45{\times}10^{-8}mol/g\;BW$) of TP, DHT, or ND. All three androgens rapidly increased weights of seminal vesicle tissue and fluid, and also increased concentrations of Cr and PCr in the tissue and fluid. However, ND was least effective in increasing seminal vesicle weights, whereas ND was as effective as, or in some cases, more effective than, TP or DHT in increasing Cr and PCr levels in the tissue and fluid. The results confirm that the accumulation of Cr and PCr in the seminal vesicles is regulated by testosterone and DHT, and also suggest that the effects of androgens on seminal vesicle growth and secretory activity may be differentiated.

• Osteoporosis and Sarcopenia
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• v.2 no.3
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• pp.140-155
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• 2016

Sex steroids influence the maintenance and growth of muscles. Decline in androgens, estrogens and progesterone by aging leads to the loss of muscular function and mass, sarcopenia. These steroid hormones can interact with different signaling pathways through their receptors. To date, sex steroid hormone receptors and their exact roles are not completely defined in skeletal and smooth muscles. Although numerous studies focused on the effects of sex steroid hormones on different types of cells, still many unexplained molecular mechanisms in both skeletal and smooth muscle cells remain to be investigated. In this paper, many different molecular mechanisms that are activated or inhibited by sex steroids and those that influence the growth, proliferation, and differentiation of skeletal and smooth muscle cells are reviewed. Also, the similarities of cellular and molecular pathways of androgens, estrogens and progesterone in both skeletal and smooth muscle cells are highlighted. The reviewed signaling pathways and participating molecules can be targeted in the future development of novel therapeutics.