Reduced mesencephalic astrocyte-derived neurotrophic factor expression by mutant androgen receptor contributes to neurodegeneration in a model of spinal and bulbar muscular atrophy pathology

Spinal and bulbar muscular atrophy is a neurodegenerative disease caused by extended CAG trinucleotide repeats in the androgen receptor gene,which encodes a ligand-dependent transcription facto r.The mutant androgen receptor protein,characterized by polyglutamine expansion,is prone to misfolding and forms aggregates in both the nucleus and cytoplasm in the brain in spinal and bulbar muscular atrophy patients.These aggregates alter protein-protein interactions and compromise transcriptional activity.In this study,we reported that in both cultured N2a cells and mouse brain,mutant androgen receptor with polyglutamine expansion causes reduced expression of mesencephalic astrocyte-de rived neurotrophic factor.Overexpressio n of mesencephalic astrocyte-derived neurotrophic factor amelio rated the neurotoxicity of mutant androgen receptor through the inhibition of mutant androgen receptor aggregation.Conversely.knocking down endogenous mesencephalic astrocyte-derived neurotrophic factor in the mouse brain exacerbated neuronal damage and mutant androgen receptor aggregation.Our findings suggest that inhibition of mesencephalic astrocyte-derived neurotrophic factor expression by mutant androgen receptor is a potential mechanism underlying neurodegeneration in spinal and bulbar muscular atrophy.

Characterization of distinct microbiota associated with androgenetic alopecia patients treated and untreated with platelet-rich plasma(PRP)

Background:Androgenic alopecia(AGA)is the most common type of hair loss in men,and there are many studies on the treatment of hair loss by platelet-rich plasma(PRP).The human scalp contains a huge microbiome,but its role in the process of hair loss remains unclear,and the relationship between PRP and the microbiome needs further study.Therefore,the purpose of this study was to investigate the effect of PRP treatment on scalp microbiota composition.Methods:We performed PRP treatment on 14 patients with AGA,observed their clinical efficacy,and collected scalp swab samples before and after treatment.The scalp microflora of AGA patients before and after treatment was characterized by amplifying the V3-V4 region of the 16 s RNA gene and sequencing for bacterial identification.Results:The results showed that PRP was effective in the treatment of AGA patients,and the hair growth increased significantly.The results of relative abundance analysis of microbiota showed that after treatment,g_Cutibacterium increased and g_Staphylococcus decreased,which played a stable role in scalp microbiota.In addition,g_Lawsonella decreased,indicating that the scalp oil production decreased after treatment.Conclusions:The findings suggest that PRP may play a role in treating AGA through scalp microbiome rebalancing.

Exogenous testosterone therapy on choroid in androgen deficiency

AIM:To investigate the effects of exogenous testosterone treatment on the choroidal parameters in patients with androgen deficiency.METHODS:Right eyes of 24 patients with androgen deficiency and 31 healthy volunteers were included in the study.The eyes were scanned for subfoveal choroidal thickness(SFCT),choroidal vascularity index(CVI),choroidstromal area(C-SA),choroid-luminal area(C-LA),choroidstromal to luminal area ratio(CSLR),and the choroidal parameters within central 1500μm of the macula(CVI1500,C-LA1500,C-SA1500,and CSLR1500)by enhanced-depth imaging optical coherence tomography(EDI-OCT)at baseline,6th and 18th weeks of the exogenous testosterone treatment.RESULTS:The mean SFCT values of the androgen deficient groups and healthy controls were 307.7±27.0 and 303.2±37.2μm(P=0.8).However,CVI,C-SA,CSLR,CVI1500,C-LA1500,and CSLR1500 were significantly different between the groups(all P<0.01).At the 6th week visit after exogenous testosterone treatment,SFCT,CVI,C-LA,and C-SA were significantly decreased,and these parameters returned to baseline levels at the 18th-week visit(all P>0.05).However,CVI1500 and LA1500 significantly increased at the end of the follow-up period(P<0.001).CONCLUSION:CVI is lower in androgen-deficient patients than in healthy subjects.The alterations in the choroid during the testosterone peak are transient in the treatment of patients with androgen deficiency.However,the increase in CVI within the central 1500μm of the macula persists even after 4mo.

Androgen signaling inhibits de novo lipogenesis to alleviate lipid deposition in zebrafish

Testosterone is closely associated with lipid metabolism and known to affect body fat composition and muscle mass in males.However,the mechanisms by which testosterone acts on lipid metabolism are not yet fully understood,especially in teleosts.In this study,cyp17a1-/-zebrafish(Danio rerio)exhibited excessive visceral adipose tissue(VAT),lipid content,and up-regulated expression and activity of hepatic de novo lipogenesis(DNL)enzymes.The assay for transposase accessible chromatinwithsequencing(ATAC-seq)results demonstrated that chromatin accessibility of DNL genes was increased in cyp17a1-/-fish compared to cyp17a1+/+male fish,including stearoyl-CoA desaturase(scd)and fatty acid synthase(fasn).Androgen response element(ARE)motifs in the androgen signaling pathway were significantly enriched in cyp17a1+/+male fish but not in cyp17a1-/-fish.Both androgen receptor(ar)-/-and wildtype(WT)zebrafish administered with Ar antagonist flutamide displayed excessive visceral adipose tissue,lipid content,and up-regulated expression and activity of hepatic de novo lipogenesis enzymes.The Ar agonist BMS-564929 reduced the content of VAT and lipid content,and down-regulated acetyl-CoA carboxylase a(acaca),fasn,and scd expression.Mechanistically,the rescue effect of testosterone on cyp17a1-/-fish in terms of phenotypes was abolished when ar was additionally depleted.Collectively,these findings reveal that testosterone inhibits lipid deposition by down-regulating DNL genes via Ar in zebrafish,thus expanding our understanding of the relationship between testosterone and lipid metabolism in teleosts.

Androgen Receptor Promotes Lung Cancer Metastasis by Modifying the miR23a-3p/EPHB2 Pathway

Objective This study aimed to investigate the reasons behind the lower survival rates in male lung cancer patients than in female lung cancer patients.Methods Through various techniques,such as Argonaute immunoprecipitation,luciferase assays,and ChIP,this study confirmed the positive effects of androgen receptor(AR)on lung cancer cell invasion across different in vitro cell lines and in vivo mouse models.Results The findings suggest that AR enhanced the invasion of lung cancer cells by modifying EPHB2 signals at the protein expression level,which in turn required changes in miRNA-23a-3p.Restoring miRNA-23a-3p could counteract the intensified invasion of lung cancer cells mediated by AR.Conclusion This study revealed that AR may facilitate the lung cancer matastasis by modulating miRNA-23a-3p/EPHB2 signaling and that targeting this signaling pathway could provide new approaches to inhibit lung cancer metastasis.

The Pathogenesis and Treatment Progress of Androgenic Alopecia

Androgenic alopecia, also known as seborrheic alopecia, is the most common hair loss disorder in dermatology clinics, mainly characterized by hair follicle miniaturization and progressive hair loss. The etiology and pathogenesis of androgenic alopecia are not clear, but may be related to heredity and androgen metabolism. Currently, minoxidil and finasteride are the only two drugs approved by the U.S. Food and Drug Administration (FDA) for AGA treatment, other treatments include oral minoxidil, hair transplantation, low energy laser therapy (LLLT), platelet-rich plasma (PRP), Chinese medicine microneedles, and combination therapy. With the development of medicine and science, we have ushered in the era of biologics and targeted therapy. In recent years, a variety of signaling pathways for androgenic alopecia have been found, which may provide a basis for targeted therapy for androgenic alopecia.

Re-Densification Effect of Pressure-Injected Peptide-Hyaluronic Acid Combination on Male Androgenic Alopecia

Introduction: Mechanism of male androgenic alopecia (MAGA) is complex and leads to an excessive hair shedding and decreased hair density. Oral, topical, and injectable autologous treatments demonstrate ability to stimulate hair re-growth, but the response is suboptimal or plateaus off. Synthetic combination of the peptide complex and hyaluronic acid (P-HA) demonstrated hair regrowth in alopecia patients. Electronically-operated pneumatic injections (EPI) generate micro-trauma in the dermis and under wound-healing conditions may enhance regeneration effect of P-HA. Methods: Subjects seeking improvement of their male pattern hair loss (Hamilton-Norwood type 2-4) received the P-HA treatments through EPI. The course included 4 treatments every two weeks over the 8-week period. In 6 months, the hair growth was assessed comparative to baseline by global clinical photography and digital phototrichograms. The treatment safety and tolerability were documented through the whole study period. Results: Twelve men (30-45 years old) completed the treatment course with high tolerability and without adverse events. Post-treatment assessment of the previously bald areas showed improved coverage on the clinical photographs. The phototrichograms demonstrated statistically significant increase in terminal hair density by 36%, cumulative hair thickness by 37%, and follicular units by 20%;all contributing to a 38% increase in cumulated hair density (all p Conclusion: Electronic pneumatic injections are well tolerated and can be safely used for the needle-free administration of the peptide-hyaluronic acid combination in MAGA therapy. We achieved significant hair re-densification in the balding scalp. The exact role of the EPI-induced impact in the hair re-growth mechanism remains to be ascertained. .

Phenotypic heterogeneity of mutations in androgen receptor gene

Androgen receptor （AR） gene has been extensively studied in diverse clinical conditions. In addition to the point mutations, trinucleotide repeat （CAG and GGN） length polymorphisms have been an additional subject of interest and controversy among geneticists. The polymorphic variations in triplet repeats have been associated with a number of disorders, but at the same time contradictory findings have also been reported. Further, studies on the same disorder in different populations have generated different results. Therefore, combined analysis or review of the published studies has been of much value to extract information on the significance of variations in the gene in various clinical conditions. AR genetics has been reviewed extensively but until now review articles have focused on individual clinical categories such as androgen insensitivity, male infertility, prostate cancer, and so on. We have made the first effort to review most the aspects of AR genetics. The impact of androgens in various disorders and polymorphic variations in the AR gene is the main focus of this review. Additionally, the correlations observed in various studies have been discussed in the light of in vitro evidences available for the effect of AR gene variations on the action of androgens.

PI3K-AKT-mTOR signaling in prostate cancer progression and androgen deprivation therapy resistance

Prostate cancer （PCa） is the second most common malignancy among men in the world. Castration-resistant prostate cancer （CRPC） is the lethal form of the disease, which develops upon resistance to first line androgen deprivation therapy （ADT）. Emerging evidence demonstrates a key role for the PI3K-AKT-mTOR signaling axis in the development and maintenance of CRPC. This pathway, which is deregulated in the majority of advanced PCas, serves as a critical nexus for the integration of growth signals with downstream cellular processes such as protein synthesis, proliferation, survival, metabolism and differentiation, thus providing mechanisms for cancer cells to overcome the stress associated with androgen deprivation. Furthermore, preclinical studies have elucidated a direct connection between the PI3K-AKT-mTOR and androgen receptor （AR） signaling axes, revealing a dynamic interplay between these pathways during the development of ADT resistance. Thus, there is a clear rationale for the continued clinical development of a number of novel inhibitors of the PI3K pathway, which offer the potential of blocking CRPC growth and survival. In this review, we will explore the relevance of the PI3K-AKT-mTOR pathway in PCa progression and castration resistance in order to inform the clinical development of specific pathway inhibitors in advanced PCa. In addition, we will highlight current deficiencies in our clinical knowledge, most notably the need for biomarkers that can accurately predict for response to PI3K pathway inhibitors.

Effect of androgen deprivation on penile ultrastructure

<abstract>Aim: To investigate the ultrastructural changes of penile corpus cavernosum and tunica albuginea in rats treated with castration or finasteride. Methods: Eighteen male Sprague-Dawley rats of nine weeks old were randomly divided into three groups with 6 rats each. Group A served as the control, Group B was castrated and Group C, treated with finasteride. Four weeks later, rats were anesthetized and blood samples obtained for the determination of serum testosterone (T) and dihydrotestosterone (DHT) levels; penile tissues were taken for scanning electron microscopy. Results: The T, free T and DHT levels in Group B and the DHT level in Group C were significantly lower than those in Group A (P<0.05). The tunica albuginea was significantly thinner in Group B than that in Group A (P<0.05), but there was no significant difference between Group C and Group A (P>0.05). Elastic fibers in the tunica albuginea of Group A were very rich and arranged regularly and undulatedly, but in Group B, most of the elastic fibers were replaced by collagenous fibers. In Group C, the tunica albuginea was mainly composed of thick and irregular-arranged collagenous fibers. In Group A, there were abundant smooth muscle fibers in the trabeculae of corpus cavernosum, but they were much less in Group C and scarce or even disappeared in Group B. In Groups B and C, the diminished/disappeared smooth muscle fibers were replaced by irregularly arranged collagenous fibers. Conclusion: In rats, androgen is essential for maintaining the normal structure of penile tunica albuginea and corpus carvenosum.

Androgen receptor signaling and mutations in prostate cancer

Normal and neoplastic growth of the prostate gland are dependent on androgen receptor （AR） expression and function. Androgenic activation of the AR, in association with its coregulatory factors, is the classical pathway that leads to transcriptional activity of AR target genes. Alternatively, cytoplasmic signaling crosstalk of AR by growth factors, neurotrophic peptides, cytokines or nonandrogenic hormones may have important roles in prostate carcinogenesis and in metastatic or androgen-independent （AI） progression of the disease. In addition, cross-modulation by various nuclear transcription factors acting through basal transcriptional machinery could positively or negatively affect the AR or AR target genes expression and activity. Androgen ablation leads to an initial favorable response in a significant number of patients; however, almost invariably patients relapse with an aggressive form of the disease known as castration-resistant or hormone-refractory prostate cancer （PCa）. Understanding critical molecular events that lead PCa cells to resist androgen-deprivation therapy is essential in developing successful treatments for hormone-refractory disease. In a significant number of hormone-refractory patients, the AR is overexpressed, mutated or genomically amplified. These genetic alterations maintain an active presence for a highly sensitive AR, which is responsive to androgens, antiandrogens or nonandrogenic hormones and collectively confer a selective growth advantage to PCa cells. This review provides a brief synopsis of the AR structure, AR coregulators, posttranslational modifications of AR, duality of AR function in prostate epithelial and stromal cells, AR-dependent signaling, genetic changes in the form of somatic and germline mutations and their known functional significance in PCa cells and tissues.

nfluence of immune inflammation on androgen receptor expression in benign prostatic hyperplasia tissue

This study was designed to investigate the association between immune inflammation and androgen receptor （AR） expression in benign prostatic hyperplasia （BPH）. We retrospectively analyzed 105 prostatectomy specimens. An immune inflammation score for each specimen was defined by combining three immunohistochemical markers （CD4, CD8 and CD20）. The immunohistochemical markers were CD4 and CD8 for T lymphocytes, CD20 for B lymphocytes and AR antibody for the AR in BPH samples. Rates of CD4, CD8, CD20 and AR expression in BPH were 20 （19.0%）, 21 （20.0%）, 101 （96.2%） and 48 （45.7%）, respectively. Total prostate volume （TPV） was higher in the immune inflammation group than in the non-immune inflammation group （62.7 ml vs. 49.2 ml, t=-2.482, P〈0.05）. Patients in the immune inflammation group had a higher serum prostate-specific antigen （PSA） than those in the non-inflammation group （7.5 ng m1-1 vs. 5.4 ng m1-1, t=-2.771, P〈0.05）. Specifically, the immune inflammation group showed a higher rate of AR expression than the non-inflammation group （56.1% vs. 28.2%, χ2=7.665, P〈0.05）. Our study revealed a strong association between immune inflammation and TPV, serum PSA and AR expression in BPH tissue. Prostate hyperplasia caused by an immune inflammatory process may contribute to BPH progression over time. Therefore, the inflammatory response involved in BPH may be a prime therapeutic target.

The andropause and memory loss: is there a link between androgen decline and dementia in the aging male?

Studies demonstrate a decline in androgens with age and this results in the andropause. The objective of this paperis to review the literature on hormonal changes that occur in the aging males and determine if there are associations be-tween decreased testosterone, dehydroepiandrosterone (DHEA) and decreased cognitive function. Trials of androgen re-placement and its impact on cognitive function will also be analyzed. Method of analysis will be by a thorough searchof articles on MEDLINE, the Internet and major abstract databases. Results of the author's own research in 302 men ofthe association of memory loss as a symptom in the andropause will be presented. In addition, the authors open trial oftestosterone replacement in hypogonadic men with Alzheimer's disease will also be presented. The results of the author'strial will be compared with other investigators. High endogenous testosterone level predicted better performance on visu-al spatial tests in several studies, but not in all studies. Likewise, testosterone replacement in hypogonadic patients im-proved cognitive functions in some but not all studies. Testosterone has also been shown to improve cognitive functionin eugonadal men. Several studies have shown that declines in DHEA may contribute to Alzheimer's disease and the re-sults of double blind studies with DHEA replacement and its effect on cognition will also be presented. In summary,there is still no consensus that androgen replacement is beneficial in cognitive decline but this option may prove promis-ing in some patients. (Asian J Androl 2001 Sep; 3: 169-174)

Androgen receptor isoforms in human prostatic cancer tissue and LNCaP cell line

Aim: To investigate the androgen receptor (AR) isoform expressions in human prostatic cancer tissue and LNCaPcell line. Methods: With high resolution isoelectric focusing (IEF) method we demonstrated the different expres-sions of AR isoforms in human prostatic cancer tissues and LNCaP cell line. Results; Data were obtained from threeprostatic cancer specimens and the LNCaP cell line. Three types of AR isoforms were detected with pI values at 6.5,6.0, and 5.3. For the 3 prostatic cancer specimens, 1 sample showed all the three types of AR isoforms, the secondspecimen expressed at 6.5 and 6.0, and the third failed to show any type of isoforms. The LNCaP cell line expressedall the three AR isoforms. Binding of ~3H-dihydrotestosterone (~3H-DHT) to these three isoforms was inhibited by the ad-dition of 100-fold excess of DHT or testosterone, while not by progesterone, oestradiol and diethylstilboestrol. Conclu-sion : The expression of AR isoforms is different in different prostate cancer tissues, which may be related to the dif-ference in the effect of anti-androgen therapy in different patients. (Asian J Androl 2001 Sep; 3: 223 - 225)

Androgen and prostatic stroma

<abstract>Aim: To investigate the effect of androgen on the proliferation, differentiation and regression of canine prostatic stromal cells in vivo and human stromal cells in vitro. Methods: Twenty-two dogs, including 15 normal prostate dogs and 7 prostatic hyperplasia dogs, had their serum concentration of testosterone and estrodiol determined by radioimmunoassay before and after castration. The expression of androgen receptor (AR) and estrogen receptor (ER) in the prostate were analysed by immunohistochemistry and semi-quantitative RT-PCR before and after castration. Light microscopy, transmission electron microscopy and TUNEL assay were carried out successively before and after castration to evaluate the prostatic histomorphology. In vitro serum-free cell cultures from human prostatic stroma were established and exposed to dihydrotestosterone (DHT). The proliferation of the cell culture was detected by MTT assay. The expression of TGFβ, bFGF, AR, and smooth muscle cell (SMC) specific proteins (myosin and/or smoothelin) were detected using immunohistochemistry and RT-PCR. The differentiation from fibroblasts to smooth muscle cells was deduced by measuring the expression of SMC specific proteins. Results: Before castration, the serum concentrations of testosterone and estrodiol were not statistically different between normal and hyperplasia groups. Following castration, the serum concentration of testosterone decreased rapidly in 2 days, and the concentration of estrodiol had no significant change compared with the pre-castration data. In the prostate, AR was presented in both the epithelial and stromal cells and the AR mRNA level was higher in hyperplasia than in normal prostate tissues (P<0.05). While ER predominantly existed in the prostate stromal cells and the ER mRNA had no difference between the hyperplasia and the normal group. Within the early phase of castration (<d7), the expression of AR was increased rapidly. Then it gradually dropped to a lower level than that of the pre-castration by the end of d90. The expression of ER remained unchanged in the whole course. The prostatic stromal cells, including SMCs and fibroblasts, diminished and underwent serial pathological changes of atrophy and apoptosis after castration. The atrophic cells were filled with huge intracellular lipofuscin. The expression of SMC myosin declined after castration, coincident with the increase in TGFβ mRNA level and decline in bFGF mRNA level. In vitro, DHT caused a weak increase in the proliferation and expression of SMC-specific proteins (P<0.05). However, DHT and bFGF together stimulated the proliferation of stromal cells significantly more than either agent alone (P<0.01). The combination of DHT and TGFβ greatly enhanced the expression of SMC-specific proteins (P<0.01) more strongly than either alone (P<0.01). Conclusions: The whole prostate gland is an androgen-sensitive organ with both the epithelium and stroma under the control of androgen. Androgen may direct the proliferation, differentiation and regression of stromal cells by regulating the expression of TGFβ, bFGF, AR and smooth muscle cell specific proteins.

Proliferation and phenotypic changes of stromal cells in response to varying estrogen/androgen levels in castrated rats

It is known that human benign prostatic hyperplasia might arise from an estrogen/androgen （E/T） imbalance. We studied the response of castrated rat prostate to different ratios of circulating E/T. The castrated male Wistar rats were randomly injected with E/T at different ratios for 4 weeks. The prostates of E/T （1：100） group showed a distinct prostatic hyperplasia response by prostatic index, hematoxylin and eosin staining, and quantitative immunohistochemical analysis of a-smooth muscle actin （SMA）. In this group, cells positive for Vimentin, non-muscle myosin heavy chain （NMMHC） and proliferating cell nuclear antigen （PCNA） increased in the stroma and epithelium. Furthermore, the mRNA levels of smooth muscle myosin heavy chain （SMMHC） and NMMHC increased. So E/T at a ratio of 1：100 can induce a stromal hyperplastic response in the prostate of castrated rats. The main change observed was an increase of smooth muscle cells, whereas some epithelial changes were also seen in the rat prostates.

Muscle function, physical performance and body composition changes in men with prostate cancer undergoing androgen deprivation therapy

Prostate cancer （PCa） is the most common visceral malignancy in men with androgen deprivation therapy （ADT） the preferred therapy to suppress testosterone production and hence tumor growth. Despite its effectiveness in lowering testosterone, ADT is associated with side effects including loss of muscle mass, diminished muscle strength, decrements in physical performance, earlier fatigue and declining quality of life. This review reports a survey of the literature with a focus on changes in muscle strength, physical function and body composition, due to short-term and long-term ADT. Studies in these areas are sparse, especially well-controlled, prospective randomized trials. Cross-sectional and longitudinal data （up to 2 years） for men with PCa treated with ADT as well as patients with PCa not receiving ADT and age-matched healthy men are presented when available. Based on limited longitudinal data, the adverse effects of ADT on muscle function, physical performance and body composition occur shortly after the onset of ADT and tend to persist and worsen over time. Exercise training is a safe and effective intervention for mitigating these changes and initial guidelines for exercise program design for men with PCa have been published by the American College of Sports Medicine. Disparities in study duration, types of studies and other patient-specific variables such as time since diagnosis, cancer stage and comorbidities may all affect an understanding of the influence of ADT on health, physical performance and mortality.

Human androgen deficiency： insights gained from androgen receptor knockout mouse models

The mechanism of androgen action is complex. Recently, significant advances have been made into our understanding of how androgens act via the androgen receptor （AR） through the use of genetically modified mouse models. A number of global and tissue-specific AR knockout （ARKO） models have been generated using the Cre-loxP system which allows tissue- and/or cell-specific deletion. These ARKO models have examined a number of sites of androgen action including the cardiovascular system, the immune and hemopoetic system, bone, muscle, adipose tissue, the prostate and the brain. This review focuses on the insights that have been gained into human androgen deficiency through the use of ARKO mouse models at each of these sites of action, and highlights the strengths and limitations of these Cre-loxP mouse models that should be considered to ensure accurate interpretation of the phenotype.

Androgen receptor signaling in hepatocellular carcinoma and pancreatic cancers

Hepatocellular carcinoma (HCC) and pancreatic cancer remain difficult to treat, and despite the ongoing development of new treatments, the overall survival rate has only modestly improved over the past decade. Liver and pancreatic progenitors commonly develop from endoderm cells in the embryonic foregut. A previous study showed that HCC and pancreatic cancer cell lines variably express androgen receptor (AR), and these cancers and the surrounding tissues also express AR. AR is a ligand-dependent transcription factor that belongs to the nuclear receptor superfamily. Androgen response element is present in regulatory elements on the AR-responsive target genes, such as transforming growth factor beta-1 (TGF beta-1) and vascular endothelial growth factor (VEGF). It is well known that the activation of AR is associated with human carcinogenesis in prostate cancer as well as HCC and pancreatic cancer and that GRP78, TGF beta, and VEGF all play important roles in carcinogenesis and cancer development in these cancers. HCC is a male-dominant cancer irrespective of its etiology. Previous work has reported that vertebrae forkhead box A 1/2 are involved in estrogen receptors and/or AR signaling pathways, which may contribute to the gender differences observed with HCC. Our recent work also showed that AR has a critical role in pancreatic cancer development, despite pancreatic cancer not being a male dominant cancer. Aryl hydrocarbon (or dioxin) receptor is also involved in both HCC and pancreatic cancer through the formation of complex with AR. It is possible that AR might be involved in their carcinogenesis through major histocompatibility complex class&#x02005;I&#x02005;chain-related gene A/B. This review article describes AR and its role in HCC and pancreatic cancer and suggests that more specific AR signaling-inhibitors may be useful in the treatment of these &#x0201c;difficult to treat&#x0201d; cancers.

Androgen and bone mass in men

<abstract>Androgens have multiple actions on the skeleton throughout life. Androgens promote skeletal growth and accumulation of minerals during puberty and adolescence and stimulate osteoblast but suppress osteoclast function, activity and lifespan through complex mechanisms. Also androgens increase periosteal bone apposition, resulting in larger bone size and thicker cortical bone in men. There is convincing evidence to show that aromatization to estrogens was an important pathway for mediating the action of testosterone on bone physiology. Estrogen is probably the dominant sex steroid regulating bone resorption in men, but both testosterone and estrogen are important in maintaining bone formation.