Effect of dihydrotestosterone on the expression of mucin 1 and the activity of Wnt signaling in mouse corneal epithelial cells

AIM： To explore the effects of the androgen dihydrotestosterone on the expression of mucin 1（MUC1） and the activity of Wnt signaling in mouse corneal epithelial cells.METHODS： Primary mouse corneal epithelial cells were isolated from the corneas of BALB/c mice. Quantitative real-time polymerase chain reaction, immunofluorescence and Western blot analysis were used to quantify the differential expression of selected genes. The androgen receptor was silenced by transfecting cells with androgen receptor sh RNAs. TOP-Flash and FOP-flash reporter plasmids were used to measure β-catenin-driven transcription. RESULTS： Dihydrotestosterone treatment increased MUC1 expression and activated the Wnt signaling pathway and led to the translocation of β-catenin and upregulation of the Wnt downstream target gene TATA box binding protein and urokinase plasminogen activator.These effects were prevented by downregulating the androgen receptor.CONCLUSION： Androgens may protect against dry eye by regulating the expression of MUC1 which is stimulated by the activation of Wnt signaling via the androgen receptor. An understanding of the mechanisms associated with androgen-mediated protection against dry eye is an important step in developing new therapies for this disease.

Combined treatment with dihydrotestosterone and lipopolysaccharide modulates prostate homeostasis by upregulating TNF-α from M1 macrophages and promotes proliferation of prostate stromal cells

Androgens and chronic inflammation,which play essential roles in the development of benign prostatic hyperplasia(BPH),are considered to be important factors in disorders of prostate homeostasis.These two factors may lead to pathological hyperplasia in the prostate transition zone of patients with BPH.However,few studies have examined the mechanism of how dihydrotestosterone(DHT)affects chronic inflammation in prostate tissue during the progression of BPH.This study examined the performance of DHT in lipopolysaccharide-treated M1 macrophages and the subsequent effects on the proliferation of prostate stromal and epithelial cells.We found that DHT increased secretion of the pro-inflammatory factor tumor necrosis factor(TNF)-αfrom M1 macrophages differentiated from THP-1 cells.The supernatant of M1 macrophages promoted the proliferation of WPMY-1 prostate stromal cells by upregulating B-cell lymphoma-extra large(Bcl-xL)and cellular Myc(c-Myc)levels by activating TNF-α-mediated nuclear factor-kappa B(NF-κB)and mitogen-activated protein kinase(MAPK)pathways.Moreover,this supernatant increased the expression of androgen receptor in WPMY-1 cells,which was TNF-α-independent.Additionally,TNF-αprotein expression was significantly higher in patients with BPH and a large prostate volume than that in those with a small prostate volume.Further analysis showed that higher serum testosterone combined with prostate-specific androgen concentrations was related to TNF-αexpression.This study suggests that DHT modulates the inflammatory environment of BPH by increasing TNF-αexpression from lipopolysaccharide-treated M1 macrophages and promotes the proliferation of prostate stromal cells.Targeting TNF-α,but not DHT,may be a promising strategy for patients with BPH.

Hair growth-promotion effects and antioxidant activity of the banana flower extract HappyAngel^(■):double-blind, placebo-controlled trial

Banana flowers contain various bioactive components, including several antioxidants with anti-inflammatory effects. However, it is unclear whether they can reduce and prevent hair loss. This study examines the effect of banana flower extracts on preventing hair loss and strengthening hair roots. The banana flower extract(HappyAngel^(■))was used to treat human hair follicle dermal papilla cells(HFDPCs)and the expression of reactive oxygen species(ROS), dihydrotestosterone(DHT), and hair-related genes(SRD5A1, SRD5A2, AR, and KROX20)were monitored. Fifty subjects were divided into a placebo group and a banana flower group. The experimental group consumed banana flower extract daily for twelve weeks and then underwent hair testing, hair-related genes analysis, collection of hair loss, and questionnaires. The results showed that the banana flower extract significantly increased hair cell growth and decreased the expression of ROS, DHT, and hair follicle growth inhibition-related SRD5A1, SRD5A2, and AR genes, and significantly increased the expression of hair growth-related KROX20 gene in HFDPCs. Consuming banana flower extract for twelve weeks increased the hair root diameter and reduced hair loss and scalp redness compared to the placebo group. Thus, banana flower extract(HappyAngel^(■))can stimulate hair growth and inhibit the activation of hair loss genes.

Androgenic regulation of novel genes in the epididymis

The epididymis is critically dependent on the presence of the testis. Although several hormones, such as retinoids and progestins, and factors secreted directly into the epididymal lumen, such as androgen binding protein and fibroblast growth factor, might play regulatory roles in epididymal function, testosterone （T） and its metabolites, dihydrotestosterone （DHT） and estradiol （E2）, are accepted as the primary regulators of epididymal structure and functions, with the former playing the greater role. To ascertain the molecular action of androgens on the epididymis, three complementary approaches were pursued to monitor changes in gene expression in response to different hormonal milieux. The first was to establish changes in gene expression along the epididymis as androgenic support is withdrawn. The second was to determine the sequence of responses that occur in an androgen deprived tissue upon re-administration of the two metabolites of T, DHT and E2. The third was to study the effects of androgen withdrawal and re-administration on gene expression in immortalized murine caput epididymidal principal cells. Specific responses were observed under each of these conditions, with an expected major difference in the panoply of genes expressed upon hormone withdrawal and re-administration; however, some key common features were the common roles of genes in insulin like growth factor/epidermal growth factor and the relatively minor and specific effects of E2 as compared to DHT. Together, these results provide novel insights into the mechanisms of androgen regulation in epididymal principal cells. （Asian J Androl 2007 July; 9： 545-553）

Effects of Melandrium firmum methanolic extract on testosterone-induced benign prostatic hyperplasia in Wistar rats

Benign prostatic hyperplasia （BPH） is an age-related disease of unknown aetiology characterized by prostatic enlargement coincident with distinct alterations in tissue histomorphology. Instead of therapeutic agents that can cause severe side effects, plant extracts are frequently used to treat BPH. In this study, we investigated whether the Melandrium firmum methanolic extract （MFME） improves BPH, using the testosterone propionate （TP）-induced BPH rat model. Castration was performed via the scrotal route under sodium pentobarbital anaesthesia. BPH in castrated rats was generated via daily subcutaneous injections of TP （3 mg kg-1） dissolved in corn oil, for 4 weeks. MFME was administered daily by oral garage at a dose of 200 mg kg-1 for 4 weeks, along with the TP injections. The control group received injections of corn oil subcutaneously. At the scheduled termination of the experiment, all rats were killed and their prostates weighed; the relative prostate weight （prostate/body weight ratio） was calculated, and histomorphological changes in the prostate were examined. Additionally, we measured the levels of testosterone and dihydrotestosterone （DHT） in the serum and the prostate. Experimentally induced BPH led to marked decreases in the relative prostate weight and the DHT levels in the serum and the prostate. Histologically, BPH was evident in the ventral lobe of the prostate, and MFME treatment suppressed the severity of the lesions. These results indicate that MFME effectively inhibits the development of BPH induced by testosterone in a rat model. Further studies will be needed to identify the compound（s） responsibility for inducing the protective effect against BPH and determine its mechanism of action,

Protective effects of gonadal hormones on spinal motoneurons following spinal cord injury

Spinal cord injury（SCI） results in lesions that destroy tissue and disrupt spinal tracts, producing deficits in locomotor and autonomic function. The majority of treatment strategies after SCI have concentrated on the damaged spinal cord, for example working to reduce lesion size or spread, or encouraging regrowth of severed descending axonal projections through the lesion, hoping to re-establish synaptic connectivity with caudal targets. In our work, we have focused on a novel target for treatment after SCI, surviving spinal motoneurons and their target musculature, with the hope of developing effective treatments to preserve or restore lost function following SCI. We previously demonstrated that motoneurons, and the muscles they innervate, show pronounced atrophy after SCI. Importantly, SCI-induced atrophy of motoneuron dendrites can be attenuated by treatment with gonadal hormones, testosterone and its active metabolites, estradiol and dihydrotestosterone. Similarly, SCI-induced reductions in muscle fiber cross-sectional areas can be prevented by treatment with androgens. Together, these findings suggest that regressive changes in motoneuron and muscle morphology seen after SCI can be ameliorated by treatment with gonadal hormones, further supporting a role for steroid hormones as neurotherapeutic agents in the injured nervous system.

Potential impact of combined inhibition of 3a-oxidoreductases and 5a-reductases on prostate cancer

Prostate cancer(PCa)growth and progression rely on the interaction between the androgen receptor(AR)and the testicular ligands,testosterone and dihydrotestosterone(DHT).Almost all men with advanced PCa receive androgen deprivation therapy(ADT).ADT lowers circulating testosterone levels,which impairs AR activation and leads to PCa regression.However,ADT is palliative and PCa recurs as castration-recurrent/resistant PCa(CRPC).One mechanism for PCa recurrence relies on intratumoral synthesis of DHT,which can be synthesized using the frontdoor or primary or secondary backdoor pathway.Androgen metabolism inhibitors,such as those targeting 5a-reductase,aldo-keto-reductase family member 3(AKR1C3),or cytochrome P45017A1(CYP17A1)have either failed or produced only modest clinical outcomes.The goal of this review is to describe the therapeutic potential of combined inhibition of 5a-reductase and 3a-oxidoreductase enzymes that facilitate the terminal steps of the frontdoor and primary and secondary backdoor pathways for DHT synthesis.Inhibition of the terminal steps of the androgen metabolism pathways may be a way to overcome the shortcomings of existing androgen metabolism inhibitors and thereby delay PCa recurrence during ADT or enhance the response of CRPC to androgen axis manipulation.

The physiological and pharmacological basis for the ergogenic effects of androgens in elite sports

Androgen doping in power sports is undeniably rampant worldwide. There is strong evidence that androgen administration in men increases skeletal muscle mass, maximal voluntary strength and muscle power. However, we do not have good experimental evidence to support the presumption that androgen administration improves physical function or athletic performance. Androgens do not increase specific force or whole body endurance measures. The anabolic effects of testosterone on the skeletal muscle are mediated through androgen receptor signaling. Testosterone promotes myogenic differentiation of multipotent mesenchymal stem cells and inhibits their differentiation into the adipogenic lineage. Testosterone binding to androgen receptor induces a conformational change in androgen receptor protein, causing it to associate with beta-catenin and TCF-4 and activate downstream Wnt target genes thus promoting myogenic differentiation. The adverse effects of androgens among athletes and recreational bodybuilders are under reported and include acne, deleterious changes in the cardiovascular risk factors, including a marked decrease in plasma high-density lipoproteins （HDL） cholesterol level, suppression of spermatogenesis resulting in infertility, increase in liver enzymes, hepatic neoplasms, mood and behavioral disturbances, and long term suppression of the endogenous hypothalamic-pituitary-gonadal axis. Androgens are often used in combination with other drugs which may have serious adverse events of their own. In spite of effective methods for detecting androgen doping, the policies for screening of athletes are highly variable in different countries and organizations and even existing policies are not uniformly enforced.

Molecular diagnosis of 5α-reductase-2 gene mutation in two Indian families with male pseudohermaphroditism

Aim： To identify the genotype of two Indians with male pseudohermaphroditism. Methods： Standard radioimmunoassay procedure was used for estimating hormonal levels. Conventional cytogenetic analysis was carded out for diagnosing the genetic sex in these subjects with genital ambiguity. Molecular analysis was carried out by standard polymerase chain reaction procedure using different sets of primers and reaction conditions specific for the 5α- reductase type 2 gene （SRDSA2） gene. Direct sequencing was carried out using the ABI Prism dye terminator sequencing kit and the ABI 310 sequencing apparatus. Results： We found an SRDSA2 gene mutation in exon 5, where arginine is substituted with glutamine （R246Q）, in two males with pseudohermaphroditism and ambiguous genitalia from unrelated families. This is the first time this mutation has been reported in individuals from India. Conclusion： Identification of the R246Q mutation of the SRDSA2 gene from two unrelated Indian families possibly extends the founder gene effect.

High performance thin layer chromatography as an effective tool for rapid screening of 5α-reductase inhibitors

Benign prostatic hyperplasia(BPH)is a common disease in men,and is known to be related to 5α-reductase,which can affect steroid metabolism.Under the promotion of 5α-reductase,testosterone can be converted into dihydrotestosterone(DHT),and excessive DHT will cause related diseases.Since BPH seriously affects the quality of life of patients,it is essential to discover effective 5α-reductase inhibitors.In this study,the simple analytical method of high performance thin layer chromatography(HPTLC)was used to screen active compounds,and seven compounds with strong activity were screened out.This research will provide a reference for studying the material basis of drugs for the treatment of BPH.

Polyphenol-Rich Olive Mill Wastewater Extract and Its Potential Use in Hair Care Products

In this work, the influence of phenol-enriched olive mill wastewater (OMWW) extract on hair growth was investigated in vitro on human follicle dermal papilla cells. OMWW has already shown great potential for use in skincare products, and its high polyphenol content is predestined to have a positive effect on hair growth. The studies included caffeine, a positive modulator of hair growth, and dihydrotestosterone, which causes hair loss in vivo, as controls. The impact of the investigated compounds on hair growth was evaluated by studies on cell viability and proliferation, the release of growth factors (insulin-like growth factor-1 and vascular endothelial growth factor), and the reduction of reactive oxygen species formation. OMWW showed a positive influence on the proliferation of the human follicle dermal papilla cells. Moreover, the extract leads to a significantly increased secretion of insulin-like growth factor-1, and a considerable reduction in reactive oxygen species formation was observed. Overall, our results show that the investigated phenol-enriched OMWW extract is a promising ingredient for hair care to improve hair growth, prevent hair loss due to oxidative stress and maintain a healthy scalp.

Uromedic^(■) Pumpkin Seed Derived Δ7-Sterols, Extract and Oil Inhibit 5α-Reductases and Bind to Androgen Receptor in Vitro

Dihydrotestosterone (DHT) is implicated in the development of benign prostate hyperplasia (BPH). We investigated if Uromedic? pumpkin (variety of Cucurbita pepo L. convar. citrullinina GREB. var. styriaca GREB) seed soft extract (active ingredients of GRANUFINK? Prosta forte 500 mg), seed oil and isolated Δ7-sterols could inhibit the conversion of [1,2,6,7-3H(N)]-testosterone to DHT by 5α-reductases. Also, we tested competition with [3H]-DHT for binding to the androgen receptor (AR). Pumpkin seed oil and pumpkin seed soft extract were identified as moderately active inhibitors of 5α-R1 and 5α-R2, with almost similar inhibitory capacities (IC50 5 mg/ml for 5α-R1 and about IC50 = 6 mg/ml for 5α-R2). The isolated Δ7-sterols were more active inhibitors (IC50 = 0.3 mg/ml for 5α-R1, IC50 = 1.0 mg/ml for 5α-R2). All three test compounds bound to the AR dose-dependently, with strong binding by Δ7-sterols (IC50 = 0.2 mg/ml) and weaker binding by pumpkin seed oil (IC50 = 0.4 mg/ml) and pumpkin seed soft extract (IC50 = 1.1 mg/ml). We propose that inhibition of 5α-reductases and competitive binding to the AR are mechanisms of action, by which the Uromedic? pumpkin seed derived test compounds, most specifically Δ7-sterols, counteract DHT and thereby exert clinically positive effects on the prostate, as well as bladder-strengthening effects.

Inhibitory effects of Tripterygium wilfordii multiglycoside on benign prostatic hyperplasia in rats

The present study was designed to evaluate the inhibitory effects of Tripterygium wilfordii multiglycoside(GTW) against testosterone-induced benign prostatic hyperplasia(BPH) in rats. A total of 45 rats were randomly divided into five groups: Group I, vehicle control group(sham-operated and treated with vehicle); Group II, BPH group; Group III, BPH rats treated with finasteride at a dose of 5 mg·kg-1; and Groups IV and V, BPH rats treated with GTW at dose levels of 10 and 20 mg·kg-1, respectively. The drugs were administered orally once a day for 14 days. Prostate weight, prostatic index, and the testosterone and dihydrotestosterone(DHT) levels in serum and prostate, and the serum prostate specific antigen(PSA) levels were measured; prostate tissues were taken for histopathological examination; and serum biochemical analysis was also performed. The BPH rats displayed an increase in prostate weight, prostatic index with increased testosterone and DHT levels in both the serum and prostate, and increased serum PSA levels. GTW treatment at both doses resulted in significant reductions in prostate weight, prostatic index, testosterone and DHT levels in both the serum and prostate, and serum PSA levels, compared with BPH group. Histopathological examination also indicated that GTW treatment at both doses inhibited testosterone-induced prostatic hyperplasia. Serum biochemical analysis showed that the liver and renal functions were normal. In conclusion, GTW inhibited testosterone-induced prostatic hyperplasia in rats, without host toxicity, providing a basis for the development of GTW as a novel therapy for BPH.

Testosterone and its metabolites： differential associations with cardiovascular and cerebrovascular events in men

As men grow older, circulating testosterone declines while the incidence of cardiovascular disease increases. Thus, the role of sex hormones as biomarkers, and possibly contributing factors to clinical manifestations of cardiovascular disease in the increasing demographic of aging men, has attracted considerable interest. This review focuses on observational studies of endogenous androgens, namely circulating testosterone and dihydrotestosterone, which have examined their associations with cardiovascular events such as myocardial infarction and stroke. Studies which have examined the associations of endogenous estrogens, namely circulating estradiol, with these outcomes are also discussed. In large prospective cohort studies of predominantly middle-aged and older men, lower circulating testosterone consistently predicts higher incidence of cardiovascular events. Of note, both lower circulating testosterone and lower dihydrotestosterone are associated with higher incidence of stroke. These associations are less apparent when myocardial infarction is considered as the outcome. Results for estradiol are inconsistent. Lower circulating testosterone has been shown to predict higher cardiovascular disease-related mortality, as has lower circulating dihydrotestosterone. It is possible that the relationship of circulating androgens to cardiovascular events or mortality outcomes may be U-shaped rather than linear, with an optimal range defining men at lowest risk. Epidemiological studies are observational in nature and do not prove causality. Associations observed in studies of endogenous androgens need not necessarily translate into similar effects of exogenous androgens. Rigorous randomized controlled trials are needed to clarify the effects of testosterone treatment on cardiovascular risk in men.

Identification of three novel SRD5A2 mutations in Chinese patients with 5α-reductase 2 deficiency

In this study,we investigated the genetics,clinical features,and therapeutic approach of 14 patients with 5a-reductase deficiency in China.Genotyping analysis was performed by direct sequencing of PCR products of the steroid 5α-reductase type 2 gene(SRD5A2).The 5a-reductase activities of three novel mutations were investigated by mutagenesis and an in vitro transfection assay.Most patients presented with a microphallus,variable degrees of hypospadias,and cryptorchidism.Eight of 14 patients(57.1%)were initially reared as females and changed their social gender from female to male after puberty.Nine mutations were identified in the 14 patients.p.G203S,p.Q6X,and p.R227Q were the most prevalent mutations.Three mutations(p.K35N,p.H162P,and p.Y136X)have not been reported previously.The nonsense mutation p.Y136X abolished enzymatic activity,whereas p.K35N and p.H162P retained partial enzymatic activity.Topical administration of dihydrotestosterone during infancy or early childhood combined with hypospadia repair surgery had good therapeutic results.In conclusion,we expand the mutation profile of SRD5A2 in the Chinese population.A rational clinical approach to this disorder requires early and accurate diagnosis,especially genetic diagnosis.