OBJECTIVETo explore the effect of the binding ability of the dihydrotestosterone(DHT) in prostate.

METHODSTwenty-two normal prostate tissues taken from accident-death corpses without serious diseases, and cytosolic and nuclear fractions were prepared with all the endogenous hormone removed from the cytosolic and nuclear fractions by ether stripping. The content of the bound 3H-DHT was assayed by adding 3H-DHT.

RESULTSThe average DHT-binding capacity of the DHT-binding protein in prostate was (0.0263 +/- 0.0047) nmol/g wet tissue. The DHT-binding capacities of cytosolic and nuclear fractions were (0.0103 +/- 0.0015) nmol/g wet tissue and (0.0155 +/- 0.0035) nmol/g wet tissue respectively, and the difference between them was very significant(P < 0.01).

CONCLUSIONSThe DHT-binding capacity of the DHT-binding protein in prostate is high and maintaining the high DHT level facilitates the effect of DHT.

Adult ; Cell Nucleus ; metabolism ; Cytoplasm ; metabolism ; Dihydrotestosterone ; metabolism ; Humans ; Male ; Prostate ; metabolism ; Protein Binding

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.
Cardiovascular Diseases/mortality* ; Dihydrotestosterone/metabolism* ; Estradiol/metabolism* ; Humans ; Incidence ; Male ; Mortality ; Myocardial Infarction/metabolism* ; Stroke/metabolism* ; Testosterone/metabolism*

In men, obesity and metabolic complications are associated with lower serum testosterone (T) and dihydrotestosterone (DHT) and an increased risk of, and mortality from, multiple chronic diseases in addition to cardiovascular disease (CVD). The causal interrelationships between these factors remain a matter of debate. In men with untreated congenital and lifelong forms of hypogonadotropic hypogonadism, there appears to be no increased risk. Men with Klinefelter's syndrome have an increased risk of various types of cancers, as well as CVD, which persist despite T therapy. In the absence of pathology of the hypothalamic-pituitary-gonadal axis, the effect of modest reductions in serum T in aging men is unclear. The prevalence of low serum T concentrations is high in men with cancer, renal disease, and respiratory disease and is likely to be an indicator of severity of systemic disease, not hypogonadism. Some population-based studies have found low serum T to be associated with a higher risk of deaths attributed to cancer, renal disease, and respiratory disease, while others have not. Although a meta-analysis of longitudinal studies has shown an association between low serum T and all-cause mortality, marked heterogeneity between studies limited a firm conclusion. Therefore, while a decrease in T particularly occurring later in life may be associated with an increase in all-cause and specific types of mortality in men, the differential effects, if any, of T and other sex steroids as compared to health and lifestyle factors are unknown at the current time.
Age Factors ; Cardiovascular Diseases/metabolism* ; Cause of Death ; Dihydrotestosterone/metabolism* ; Humans ; Hypogonadism/metabolism* ; Klinefelter Syndrome/metabolism* ; Male ; Mortality ; Obesity/metabolism* ; Testosterone/metabolism*

UNLABELLEDTo study the androgen dependence of the neurotransmitter, calcitonin gene-related peptide (CGRP) in rat penis.

METHODSForty-four Sprague-Dawley rats were randomly divided into Group A (intact controls), Group B (castrated) and Group C (gavaged with finasteride 4.5 mg.kg(-1).day(-1)). Four and ten weeks later respectively, half of rats in each group were anaesthetized. Blood samples were taken for the measurement of serum testosterone and dihydrotestosterone (DHT) by means of radioimmunoassay. Penile samples were harvested for the investigation of calcitonin gene related peptide (CGRP)-immunoreactive nerve fibers with immunohistochemistry. The computer-assisted imaging analysis system was applied to calculate the area proportion of the CGRP-positive nerve fibers (CGRP-PNF) in each group.

RESULTS1) Both 4 and 10 weeks later, testosterone and DHT levels in Group B decreased significantly compared with those in Group A, (P <0.05, P <0.01, respectively); DHT level in Group C was also significantly decreased in comparison with that in Group A for both 4- and 10- week animals (P <0.05); 2) There was no significant differences in area proportion of CGRP-PNF among Groups A, B and C 4 weeks after treatments (P >0.05); However, 10 weeks later, the proportion of CGRP-PNF in Groups B and C was significantly less than that in Group A (P <0.01); 3) The proportion of CGRP-PNF of 4-week animals in Groups B and C was significantly higher than that of 10-week animals (P <0.05).

CONCLUSIONThe expression of neurotransmitter, CGRP may depend on androgens, including testosterone and DHT in rat penis.

Androgens ; metabolism ; Animals ; Calcitonin Gene-Related Peptide ; metabolism ; Dihydrotestosterone ; blood ; Gene Expression Regulation ; Immunohistochemistry ; Male ; Penis ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Testosterone ; blood

BACKGROUND5α-Reductase inhibitors (5α-RI) act by inhibiting the conversion of testosterone to dihydrotestosterone (DHT), thereby preventing DHT induced benign prostatic hyperplasia. The existing 5α-RIs can be classified into two types: competitive and noncompetitive. Currently, limited evidence is available concerning the effect differences between the two types of 5α-RI on androgens. The purpose of this study was to assess the effects of competitive and noncompetitive 5α-RIs on serum and intra-prostatic androgens in beagle dogs.

METHODSTwenty beagles with spontaneous benign prostatic hyperplasia were randomly allocated into two groups: epristeride group (n = 10) in which beagles were treated with epristeride at 1 mg/kg once a day for 3 months, and finasteride group (n = 10) in which beagles were treated with finasteride at 1 mg/kg once a day for 3 months. The levels of intra-prostatic testosterone and DHT were measured before treatment and on day one after three months medication. Serum levels of testosterone and DHT were measured at the same time points. Changes in androgen levels before and after treatment were analyzed, and comparisons were made within each treatment group and between treatment groups.

RESULTSAfter 3-month treatment, serum and intra-prostatic DHT levels all decreased significantly in both the epristeride and finasteride groups. The change of DHT in serum was significantly higher in the finasteride group (-14% and -43% in epristeride and finasteride groups respectively, with P < 0.001); however there was no significant difference in the changes of intra-prostatic DHT between the two groups (-47% and -51% in epristeride and finasteride groups, respectively, P = 0.304). The decreases in DHT levels were accompanied by reciprocal increases in serum and intra-prostatic testosterone levels. Changes of testosterone were significantly higher in finasteride group both in serum (20% and 42% in epristeride and finasteride groups, respectively, P < 0.001) and in prostate tissue (18% and 29% in epristeride and finasteride groups, respectively, P = 0.004).

CONCLUSIONSTwo types of 5α-RI have similar effects in reducing DHT in prostate tissue in beagles. Competitive 5α-RI may reduce serum DHT to a greater scale, and significantly increase testosterone in beagle serum and prostate.

5-alpha Reductase Inhibitors ; pharmacology ; Androgens ; blood ; metabolism ; Androstadienes ; pharmacology ; Animals ; Dihydrotestosterone ; blood ; metabolism ; Dogs ; Finasteride ; pharmacology ; Male ; Prostate ; drug effects ; metabolism

Epidemiological studies hint at a beneficial influence of endogenous circulating testosterone (T), or its metabolite dihydrotestosterone (DHT), such that men with lower concentrations of T or DHT appear to have poorer health outcomes including frailty, diabetes, cardiovascular disease, and mortality. Small interventional studies of T have shown favorable effects on surrogate outcome measures, but a large randomized controlled trial (RCT) with the prespecified outcome of cardiovascular events has not been performed and would be logistically demanding. In the absence of such a definitive RCT, there is a controversy about the cardiovascular risks of T-therapy fuelled by contradictory findings from retrospective analyses of insurance databases of men prescribed T. The US Testosterone Trials (T-Trials) are the largest published RCTs of T-therapy in older men with symptoms or signs of hypogonadism and circulating T <9.54 nmol l⁻¹ at baseline. The T-Trials showed a modest benefit of T-therapy over a 12-month period on sexual function, a significant benefit in bone density and for anemia and neutral effect on cognition. The T-Trials cardiovascular sub-study was designed to determine the effects of T in these older men, and there was a statistically significant difference in the increase in noncalcified plaque volume in the T-treated group compared to placebo, but it is difficult to interpret these results due to differences in baseline coronary plaque burden (>50% difference) between the treatment and placebo arms of the subset involved. Therefore, there continues to be ongoing uncertainty over the effect of T-therapy on the cardiovascular system in men.
Age Factors ; Androgens/therapeutic use* ; Cardiovascular Diseases/metabolism* ; Dihydrotestosterone/metabolism* ; Hormone Replacement Therapy ; Humans ; Hypogonadism/metabolism* ; Male ; Protective Factors ; Risk Factors ; Testosterone/therapeutic use*

AIMTo examine the physiological role of the androgen receptor (AR) in the PC-3 cell line by transfecting full-length functional AR cDNA driven by its natural human AR promoter.

METHODSWe generated an AR-expressing PC-3(AR)9 stable clone that expresses AR under the control of the natural human AR promoter and compared its proliferation to that of the PC-3(AR)2 (stable clone that expresses AR under the control of the cytomegalovirus (CMV) promoter, established by Heisler et al.) after androgen treatment.

RESULTSWe found that dihydrotestosterone (DHT) from 0.001 nmol/L to 10 nmol/L induces cell cycle arrest or inhibits proliferation of PC-3(AR)2 compared with its vector control, PC-3(pIRES). In contrast, PC-3(AR)9 cell growth slightly increased or did not change when treated with physiological concentrations of 1 nmol/L DHT.

CONCLUSIONThese data suggest that intracellular control of AR expression levels through the natural AR promoter might be needed for determining AR function in androgen-independent prostate cancer (AIPC) PC-3 cells. Unlike previous publications that showed DHT mediated suppression of PC-3 growth after transfection of viral promoter-driven AR overexpression, we report here that DHT-mediated PC-3 proliferation is slightly induced or does not change compared with its baseline after reintroducing AR expression driven by its own natural promoter, as shown in PC-3(AR)9 prostate cancer cells.

Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; DNA, Complementary ; biosynthesis ; Dihydrotestosterone ; pharmacology ; Humans ; Male ; Promoter Regions, Genetic ; Prostatic Neoplasms ; metabolism ; pathology ; Receptors, Androgen ; biosynthesis ; genetics ; Transfection

OBJECTIVETo determine the expression of Skp2 in different prostate cancer (PCa) cell lines and tissues, and explore its influence on the androgen receptor (AR) signaling pathway and development of castration-resistant prostate cancer (CRPC).

METHODSThe expression levels of Skp2 and AR in different PCa cell lines were detected by Western blot. After knockdown of Skp2 in the C4-2 and 22RV1 cells transfected with shRNA, the expressions of AR and P27 were determined and the activity of ARR3-Luc measured by dual-luciferase reporter gene assay following treatment with dihydrotestosterone (DHT). The expressions of AR and Skp2 in human naïve PCa or CRPC specimens were detected by immunohistochemical staining followed by analysis of their differences and correlation.

RESULTSThe Skp2 protein expression level was significantly higher in the C4-2 or 22RV1 cells than in the LNCaP cells. DHT treatment increased the expression of Skp2 in the C4-2 cells, but knock-down of Skp2 significantly up-regulated the expression of the well-known downstream protein P27 and down-regulated that of AR. Consistently, DHT treatment increased the activity of ARR3-Luc, while knockdown of Skp2 remarkably decreased it in the C4-2 and 22RV1 cells (P < 0.05). In addition, significantly higher expressions of Skp2 and AR were observed in the CRPC than in the naïve specimens (P < 0.05), with a positive correlation between the two proteins (r = 0.658 1, P < 0.05).

CONCLUSIONSkp2 can enhance the expression and transcription activity of the AR protein in CRPC cells or tissues and is promising to be a critical molecular therapeutic target.

Androgens ; pharmacology ; Cell Line, Tumor ; Dihydrotestosterone ; pharmacology ; Disease Progression ; Gene Knockdown Techniques ; Humans ; Male ; Neoplasm Proteins ; genetics ; metabolism ; Prostatic Neoplasms, Castration-Resistant ; metabolism ; Receptors, Androgen ; genetics ; metabolism ; S-Phase Kinase-Associated Proteins ; physiology ; Transcriptional Activation ; Up-Regulation

OBJECTIVETo explore the molecular mechanism of dutasteride inhibiting fertility by studying its effects on the expressions of the epididymal epithelial junction proteins Claudin1 and β-catenin in rats.

METHODSSixteen 3-month-old SD male rats were equally divided into an experimental and a negative control group to be treated intragastrically with dutasteride at 40 mg/kg per day and the same dose of solvent, respectively, for 14 consecutive days. Then, the sperm motility and morphology of the rats were detected by computer-assisted sperm analysis, the serum levels of testosterone (T) and dihydrotestosterone (DHT) measured by ELISA, changes in the tight junction of epididymal cells observed under the transmission electron microscope, the protein and gene expressions of Claudin1 and β-catenin determined by RT-PCR and immunohistochemistry, and the conception rate of the mated female rats calculated.

RESULTSDutasteride significantly suppressed the serum DHT level, sperm motility, and fertility of the rats (P <0.05). Interspaces between epididymal epithelial cell tight junctions were observed, the volume of epididymal fluid obviously increased, and the expressions of Claudin1 and β-catenin gene and protein remarkably downregulated in the experimental rats (P <0.05).

CONCLUSIONDutasteride can significantly inhibit the fertility of male rats by reducing the serum DHT level, suppressing Claudin1 and β-catenin expressions, and damaging epididymal epithelial cell junctions.

Animals ; Azasteroids ; pharmacology ; Claudin-1 ; metabolism ; Dihydrotestosterone ; blood ; Dutasteride ; Epididymis ; drug effects ; metabolism ; Female ; Fertility ; drug effects ; Humans ; Intercellular Junctions ; drug effects ; Male ; Rats ; Rats, Sprague-Dawley ; Sperm Motility ; drug effects ; Testosterone ; blood ; Urological Agents ; pharmacology ; beta Catenin ; metabolism

OBJECTIVETo investigate the effect of dihydrotestosterone (DHT) on the gene transcriptions and expressions of Smad3 and Smad4 in androgen dependent prostate cancer cell line LNCaP, and whether this effect can be suppressed by the androgen receptor inhibitor flutamide.

METHODSThe androgen dependent prostate cancer cell line LNCaP was cultured in RPMI 1640 medium and treated with different concentrations of DHT(2, 10, 50 nmol/L) and flutamide (100 nmol/L). Quantitative reverse transcription PCR (RT-PCR) was used to detect the mRNAs of Smad3 and Smad4. The expressions of Smad3 and Smad4 protein were detected by Western blot assay.

RESULTSCompared with the control group without any DHT or flutamide, higher concentration(10, 50 nmol/L) of DHT enhanced the transcription of Smad3 mRNA (P <0.05). Serial concentrations of DHT increased the expression of Smad3 protein(P < 0.05). Flutamide inhibited the up-regulation of both Smad3 mRNA transcription and expression significantly (P <0.05). 10 nmol/L DHT significantly suppressed the transcription of Smad4 (P <0.05). There was considerable suppressions of Smad4 expression at the presence of DHT in different concentrations (P < 0.05). And the degree of this suppression was more significant than that of DHT on Smad4 mRNA transcription. Flutamide inhibited the suppressive effects of DHT on both Smad4 mRNA transcription and expression.

CONCLUSIONDHT can enhance the transcription and expression of Smad3, while it decreases the transcription and expression of Smad4 in LNCaP cell line. There is a possible crosstalk between the AR signal and TGF-beta signal passways at the level of Smads.

Androgens ; physiology ; Cell Line, Tumor ; Dihydrotestosterone ; pharmacology ; Flutamide ; pharmacology ; Humans ; Male ; Neoplasms, Hormone-Dependent ; metabolism ; Prostatic Neoplasms ; metabolism ; RNA, Messenger ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; Smad3 Protein ; biosynthesis ; genetics ; Smad4 Protein ; biosynthesis ; genetics ; Transcription, Genetic