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PubMed1988

[Which hormone therapy should be used in advanced breast carcinoma in males?].

A 76-year-old man with advanced carcinoma of the breast who had not been orchiectomized underwent sequential hormonal treatment. The tumour progressed during monotherapy with dexamethasone. Objective regression of the tumour followed sequential administration of tamoxifen (twice) and the two aromatase inhibitors, aminoglutethimide and testololactone. In addition, his condition remained stable on two progestogens in high doses, medroxyprogesterone acetate and megestrol acetate.

Adenocarcinoma↗
PubMed2001

Ampullary carcinoma developing after androgenic steroid therapy for aplastic anemia: Report of a case.

Sex steroids influence the development and course of human genital carcinomas including breast, testis, prostata, and ovarian cancers. (1) Other carcinomas such as hepatoma, cholangioma, and pancreatic cancer have also been reported to be related to sex hormones. (2-4) The existence of sex hormone receptors has been demonstrated immunohistochemically in specimens of these diseases. We recently encountered a patient in whom an ampullary carcinoma developed 39 months after the start of androgenic steroid therapy for aplastic anemia. Immunohistochemic analysis of resected tumor specimens of the patient suggested a possible hormonal effect on the tumor oncology.

Adenocarcinoma↗
PubMed2003

3 beta-acetoxyandrost-1,5-diene-17-ethylene ketal functions as a potent antiandrogen with marginal agonist activity.

The majority of available antiandrogens have been reported to possess agonist activity to induce prostate-specific antigen, which might result in antiandrogen withdrawal syndrome. Here we report the identification of 3 beta-acetoxyandrost-1,5-diene-17-ethylene ketal (ADEK) from dehydroepiandrosterone metabolites and derivatives as a potent antiandrogen. We found ADEK could interrupt androgen binding to the androgen receptor (AR) and suppress androgen-induced transactivations of WT AR and a mutant AR in prostate cancer cells. ADEK inhibited prostate-specific antigen expression as well as growth in LNCaP prostate cancer cells stimulated by androgen. Importantly, ADEK had only marginal agonist effects, as compared with commonly used antiandrogens such as hydroxyflutamide and bicalutamide, leading to a lower possibility of inducing withdrawal response. Moreover, ADEK could block an adrenal androgen androstenediol-induced AR transactivation that hydroxyflutamide and bicalutamide failed to block. These unique antiandrogenic activities make ADEK a potential therapeutic compound that might be able to inhibit AR-mediated prostate cancer progression. Further in vivo studies might facilitate the development of a better antiandrogen for the treatment of prostate cancer.

Androgen Antagonists↗
PubMed1980

Photoaffinity labeling of rat androgen binding protein.

The photoinactivation and photoaffinity labeling of androgen binding sites present in cytosol prepared from intact sexually mature rat epididymides have been demonstrated by using unlabeled and [3H]-labeled 17 beta-hydroxy-4,6-androstadien-3-one. Both photoinactivation and photolabeling are dependent upon exposure to light. These processes are inhibited when photolysis is conducted in the presence of the photoinert compound 17 beta-hydroxy-5 alpha-androstan-3-one, suggesting that steroid-specific sites are involved in the reactions. The labeled steroid-specific product of photolysis is macromolecular with a molecular weight of 47,000 as determined by electrophoresis on polyacrylamide gels containing NaDodSO4, and proteinaceous because digestion of the cytosol with pronase before photolysis eliminates steroid-specific binding. After photolysis, the protein-steroid complex has the ability to withstand dissociation during electrophoresis under denaturing conditions, and unlabeled 17 beta-hydroxy-5 alpha-androstan-3-one fails to displace the label from the complex. Thus, the binding of [3H]17 beta-hydroxy-4,6-androstadien-3-one to the cytosolic protein is covalent. This steroid-specific product is identified as an androgen binding protein of testicular origin by its comigration with native androgen binding protein on nondenaturing polyacrylamide gels and by its molecular weight which is within the range reported for androgen binding protein subunits.

Affinity Labels↗
PubMed1999

Two distinct isoforms of cDNA encoding rainbow trout androgen receptors.

Androgens play an important role in male sexual differentiation and development. The activity of androgens is mediated by an androgen receptor (AR), which binds to specific DNA recognition sites and regulates transcription. We describe here the isolation of two distinct rainbow trout cDNA clones, designated rtAR-alpha and rtAR-beta, which contain the entire androgen receptor coding region. Comparison of the predicted amino acid sequence of rtAR-alpha to that of rtAR-beta revealed 85% identity. Interestingly, despite this high homology, rtAR-alpha activated transcription of an androgen-responsive reporter gene in co-transfection assays, but rtAR-beta did not. These results suggest that rainbow trout contains two distinct isoforms of androgen receptors whose functions differ. The region of rtAR-beta responsible for its inactivity was mapped to its ligand binding domain by analyzing chimeras of the rtAR-alpha, rtAR-beta, and rtGR-I (glucocorticoid) receptors. Alteration of any one of three out of four segments within this domain restored activity. Extracts made from COS-1 cells transfected with an rtAR-alpha expression plasmid produced a high level of [3H]mibolerone binding, whereas no binding was observed by extracts of cells transfected with an rtAR-beta expression plasmid. These data demonstrate that the lack of transactivation activity of rtAR-beta is due to its inability to bind hormone.

Amino Acid Sequence↗
PubMed2000

Structural evidence for ligand specificity in the binding domain of the human androgen receptor. Implications for pathogenic gene mutations.

The crystal structures of the human androgen receptor (hAR) and human progesterone receptor ligand-binding domains in complex with the same ligand metribolone (R1881) have been determined. Both three-dimensional structures show the typical nuclear receptor fold. The change of two residues in the ligand-binding pocket between the human progesterone receptor and hAR is most likely the source for the specificity of R1881 to the hAR. The structural implications of the 14 known mutations in the ligand-binding pocket of the hAR ligand-binding domains associated with either prostate cancer or the partial or complete androgen receptor insensitivity syndrome were analyzed. The effects of most of these mutants could be explained on the basis of the crystal structure.

Amino Acid Sequence↗
PubMed2001

The androgen receptor represses transforming growth factor-beta signaling through interaction with Smad3.

In the prostate, androgens negatively regulate the expression of transforming growth factor-beta (TGF-beta) ligands and receptors and Smad activation through unknown mechanisms. We show that androgens (dihydrotestosterone and R1881) down-regulate TGF-beta1-induced expression of TGF-beta1, c-Fos, and Egr-1 in the human prostate adenocarcinoma cell line, LNCaP. Moreover, 5alpha-dihydrotestosterone (DHT) inhibits TGF-beta1 activation of three TGF-beta1-responsive promoter constructs, 3TP-luciferase, AP-1-luciferase, and SBE4(BV)-luciferase, in LNCaP cells either with or without enforced expression of TGF-beta receptors (TbetaRI and TbetaRII). Similarly, DHT inhibits the activation of Smad-binding element (SBE)4(BV)-luciferase by either constitutively activated TbetaRI (T204D) or constitutively activated Smad3 (S3*). Activation of SBE4(BV)-luciferase by S3* in the NRP-154 prostatic cell line, which is androgen receptor (AR)-negative but highly responsive to TGF-beta1, is blocked by co-transfection with either full-length AR or AR missing the DNA binding domain. Immunoprecipitation and GST pull-down assays show that AR directly associates with Smad3 but not Smad2 or Smad4. Electrophoretic mobility shift assays indicate that the AR ligand binding domain directly inhibits the association of Smad3 to the Smad-binding element. In conclusion, our data demonstrate for the first time that ligand-bound AR inhibits TGF-beta transcriptional responses through selectively repressing the binding of Smad3 to SBE.

Adenocarcinoma↗
PubMed2002

Ligand-independent activation of the androgen receptor by interleukin-6 and the role of steroid receptor coactivator-1 in prostate cancer cells.

The androgen receptor (AR) can be activated in the absence of androgens by interleukin-6 (IL-6) in human prostate cancer cells. The events involved in ligand-independent activation of the AR are unknown, but have been suggested to involve phosphorylation of the AR itself or a receptor-associated protein. Steroid receptor coactivator-1 (SRC-1) has been shown to interact with the human AR and to modulate ligand-dependent AR transactivation and is regulated by phosphorylation by MAPK. To date, no one has examined the role of SRC-1 in ligand-independent activation of the AR by IL-6 or other signaling pathways known to activate the full-length receptor. This study addressed this and has revealed the following. 1) SRC-1 similarly enhanced ligand-independent activation of the AR by IL-6 to the same magnitude as that obtained via ligand-dependent activation. 2) Androgen and IL-6 stimulated the MAPK pathway. 3) MAPK was required for both ligand-dependent and ligand-independent activation of the AR. 4) Phosphorylation of SRC-1 by MAPK was required for optimal ligand-independent activation of the AR by IL-6. 5) Protein-protein interaction between endogenous AR and SRC-1 was dependent upon treatment of LNCaP cells with IL-6 or R1881. 6) Protein-protein interaction between the AR N-terminal domain and SRC-1 was independent of MAPK. 7) Ligand-independent activation of the AR did not occur by a mechanism of overexpression of either solely wild-type SRC-1 or mutant SRC-1 that mimics its phosphorylated form.

Genes, Reporter↗
PubMed2003

Plant-derived 3,3'-Diindolylmethane is a strong androgen antagonist in human prostate cancer cells.

3,3'-Diindolylmethane (DIM) is a major digestive product of indole-3-carbinol, a potential anticancer component of cruciferous vegetables. Our results indicate that DIM exhibits potent antiproliferative and antiandrogenic properties in androgen-dependent human prostate cancer cells. DIM suppresses cell proliferation of LNCaP cells and inhibits dihydrotestosterone (DHT) stimulation of DNA synthesis. These activities were not produced in androgen-independent PC-3 cells. Moreover, DIM inhibited endogenous PSA transcription and reduced intracellular and secreted PSA protein levels induced by DHT in LNCaP cells. Also, DIM inhibited, in a concentration-dependent manner, the DHT-induced expression of a prostate-specific antigen promoter-regulated reporter gene construct in transiently transfected LNCaP cells. Similar effects of DIM were observed in PC-3 cells only when these cells were co-transfected with a wild-type androgen receptor expression plasmid. Using fluorescence imaging with green fluorescent protein androgen receptor and Western blot analysis, we demonstrated that DIM inhibited androgen-induced androgen receptor (AR) translocation into the nucleus. Results of receptor binding assays indicated further that DIM is a strong competitive inhibitor of DHT binding to the AR. Results of structural modeling studies showed that DIM is remarkably similar in conformational geometry and surface charge distribution to an established synthetic AR antagonist, although the atomic compositions of the two substances are quite different. Taken together with our published reports of the estrogen agonist activities of DIM, the present results establish DIM as a unique bifunctional hormone disrupter. To our knowledge, DIM is the first example of a pure androgen receptor antagonist from plants.

Adenocarcinoma↗
PubMed2003

Repressors of androgen and progesterone receptor action.

Androgen and progesterone receptors (AR and PR) are two determining factors in gonadal differentiation that are highly expressed in developing and mature gonads. Loss of AR results in XY sex reversal and mutations causing reduced AR activity lead to varying degrees of defects in masculinization. Female PR knockout mice are infertile due to ovarian defects. While much has been discovered about positive regulation of these receptors by coactivators little is known about repression of the transcriptional activity of AR and PR in the presence of agonists. In this study we assessed the effect of SMRT and DAX-1 on AR and PR activity in the presence of both agonists and partial antagonists. We show that SMRT and DAX-1 repress agonist-dependent activity of both receptors, and the mechanism of repression includes disruption of the receptor dimer interactions rather than recruitment of histone deacetylases. We demonstrate that endogenous agonist-bound PR and DAX-1 in T47D breast cancer cells and endogenous AR and DAX-1 in LNCaP prostate cancer cells can be coimmunoprecipitated suggesting that the interaction is physiological. Surprisingly, although DAX-1 represses partial antagonist activity of AR, it was ineffective in repressing partial antagonist induced activity of PR. In contrast to most reported repressors, the expression of DAX-1 is restricted. We found that although DAX-1 is expressed in normal human prostate, its expression is strongly reduced in benign prostatic hyperplasia suggesting that DAX-1 plays a role in limiting AR activity in prostate.

Animals↗
PubMed2004

Pharmacokinetics of S-3-(4-acetylamino-phenoxy)-2-hydroxy-2-methyl-N-(4-nitro- 3-trifluoromethyl-phenyl)-propionamide in rats, a non-steroidal selective androgen receptor modulator.

1: S-3-(4-acetylamino-phenoxy)-2-hydroxy-2-methyl-N-(4-nitro-3-trifluoromethyl-phenyl)-propionamide (also known as S-4) is a non-steroidal selective androgen receptor modulator demonstrating tissue-selective androgenic and anabolic effects. The purpose of the present study was to examine the systemic pharmacokinetics, elimination and oral bioavailability of S-4 in rats. 2: Thirty-five male Sprague-Dawley rats weighing approximately 250 g were randomly assigned to one of seven treatment groups. Intravenous doses of 0.5, 1, 10, and 30 mg kg(-1) were given via a jugular catheter. Oral doses of 1, 10 and 30 mg kg(-1) were administered via gavage. Plasma concentrations were determined using a validated high-performance liquid chromatography or by a high-performance liquid chromatography/mass spectrometry method. 3: Clearances ranged between 1.0 and 2.1 ml min(-1) kg(-1) and varied with dose. The volume of distribution was approximately 0.448 l kg(-1) in all treatment groups. Oral bioavailability was also dose dependent, with the lower doses showing complete oral bioavailability. The half-life of S-4 over the dose range tested was between 2.6 and 5.3 h. 4: It was demonstrated that S-4 is rapidly absorbed, slowly cleared, and has a moderate volume of distribution in rats. The pharmacokinetics and oral bioavailability of S-4 indicate that it is an excellent candidate for clinical development.

Acetamides↗
PubMed1976

Androgens and male sexual function: a review of human studies.

The scope of this article will be a review and brief discussion of recently gathered information on androgens and sexual behavior in men. It will include experimental observations on the covariance between androgens, mainly testosterone, and sexual functioning in normal heterosexual men and studies on sexual dysfunction and homo-sexual behavior. The effects of castration, hypogonadal conditions, hormonal replacement, and endogenous testosterone variations on sexual behavior are examined. Further psychoendocrine studies, are necessary to evaluate the role of gonadal hormone production in impotency. Current pharmacological research does not furnish specific evidence, that the administration of androgens or preparations that stimulate the secretion of endogenous androgens have beneficial effects on functional impotence. After reviewing the studies on male homosexuality and androgen levels, the article concludes that it has not been established that homosexual men are characterized by abnormalities in plasma testosterone.

Adolescent↗
PubMedDate not supplied

Female hypoactive sexual disorder: case studies of physiologic androgen replacement.

Menopause, surgical or naturally occurring, with reduced or deficient ovarian functioning has a major impact on morbidity and mortality in mid- to late life. A growing body of literature notes the role of androgens in maintaining women's health and emotional well-being. The administration of physiologic levels of testosterone replacement therapy as an adjunct to estrogen replacement requires further investigation. The Sexual Energy Scale was used to measure the patient's subjective experience of vitality or sexual energy with androgen replacement therapy. Three cases of women who had undergone a total abdominal hysterectomy with bilateral oophorectomy with complaints consistent with female hypoactive sexual desire disorder and free testosterone levels of < 2.0 pg/ml are presented. Physiologic androgen replacement is helpful in increasing sexual desire for some women.

Adult↗
PubMedDate not supplied

Expression of Bcl-2 and Bax in rhesus monkey testis during germ cell apoptosis induced by testosterone undecanoate.

Apoptosis occurs spontaneously during spermatogenesis and can be induced by androgen withdrawal. However, the molecular events governing apoptosis have not been characterized. To study the molecular mechanism of apoptosis induced by a high dose of testosterone undecanoate (TU), the authors examined the temporal changes in proapoptotic Bax and antiapoptotic Bcl-2 in TU-treated monkey testes. Apoptotic cells were identified in tissue sections by in situ end labeling of fragmented DNA. The results showed that a great deal of the apoptotic cells occurred in the testes on day 30 after TU injection and that the dominant apoptotic germ cells are spermatocytes and spermatids. The expression of Bcl-2 and Bax was assessed by immunohistochemical method and Western blot. As compared with that of normal testes, the levels of Bcl-2 protein increased significantly from 7 to day 14 while that of Bax protein was almost unchanged in the testes from day 7 up to day 60 after TU treatment. Bcl-2 was localized to the spermatids in the normal testes and temporarily distributed in both the cytoplasm and nucleus of those cell types susceptible to TU-induced apoptosis on day 14 after TU injection. Therefore, it is suggested that Bax may not play a role in initiating germ cell apoptosis induced by TU injection and that the evaluation in Bcl-2 expression may represent a survival mechanism for the remaining germ cell.

Animals↗
PubMed1992

The inhibition of rat adrenal cytochrome P-45011 beta gene expression by androgens.

The synthetic androgen methylandrostenediol (MAD) and the naturally occurring one, testosterone, both bring about hypertensive cardiovascular disease when chronically administered to rats. The pathogenesis of this form of experimental hypertension is thought to result from inhibition of steroid 11 beta-hydroxylase activity. In contrast to the above androgens, 19-nortestosterone, androstenedione and dehydroepiandrosterone (DHEA) have been reported to be without effect in elevating blood pressure. To examine the mechanism(s) involved, we have in this study compared the effects of a number of androgens on adrenal cytochrome P- 45011 beta enzyme and mRNA steady state levels. These parameters were also correlated with the ability of adrenal mitochondria isolated from these groups to hydroxylate 11-deoxycorticosterone (DOC) to corticosterone and 18-hydroxy-11-deoxycorticosterone (18-hydroxy-DOC). Rats treated for seven days with 10 mg per day of dihydrotestosterone, testosterone, 19-nortestosterone or MAD showed a profound decrease in cytochrome P-45011 beta mRNA levels (to less than 20% of controls). This was accompanied by similar changes in both the level and activity of the enzyme. Androstenedione and DHEA were less potent in effecting these changes. In addition, for MAD and testosterone we tested the dose dependence of these changes and found that increasing doses (0.1 mg to 10 mg per day) of either androgen caused progressive decreases in the parameters measured. To assess selectivity we also determined the steady state level of cytochrome P-450scc mRNA in rats treated with the various androgens. In contrast to what was found with cytochrome P-45011 beta, the mRNA transcript for cytochrome P-450scc was equal to or above control levels. We conclude that, in general, the extent of inhibition of cytochrome P-45011 beta enzyme and mRNA level by a given androgen correlates with its reported facility in producing hypertension in rats. Increased secretion of DOC continues to be a likely mechanism for the development of this hypertension but with some androgens extra-adrenal effects may be involved.

Adrenal Glands↗
PubMedDate not supplied

Voice problems in female-to-male transsexuals.

Voice therapy with the aim of raising a client's fundamental frequency is a common practice in the reassignment of male-to-female transsexuals. In female-to-male transsexuals on the other hand voice therapy is usually not considered since the administration of androgens is assumed automatically to change the voice in the direction of the desired sex. The present study examined whether the voice change in female-to-male transsexuals is indeed as straightforward as it is assumed. Results from a sample survey involving 16 female-to-male transsexuals and longitudinal data from two clients suggest that the voice change in female-to-male transsexuals is not always totally unproblematic. A voice assessment and some counselling before the hormone therapy are recommended.

Adult↗
PubMed1997

Molecular analysis of the androgen-receptor gene in a family with receptor-positive partial androgen insensitivity: an unusual type of intronic mutation.

In the coding part and the intron-exon boundaries of the androgen-receptor gene of a patient with partial androgen insensitivity, no mutation was found. The androgen receptor of this patient displayed normal ligand-binding parameters and migrated as a 110-112-kD doublet on SDS-PAGE in the absence of hormone. However, after culturing of the patient's genital skin fibroblasts in the presence of hormone, the slower-migrating 114-kD protein, which reflects hormone-dependent phosphorylation, was hardly detectable. Furthermore, receptor protein was undetectable in the nuclear fraction of the fibroblasts, after treatment with hormone, which is indicative of defective DNA binding. By sequencing part of intron 2, a T-->A mutation was found 11 bp upstream of exon 3. In our screening of 102 chromosomes from unrelated individuals, this base-pair substitution was not found, indicating that it was not a polymorphism. mRNA analysis revealed that splicing involved a cryptic splice site, located 71/70 bp upstream of exon 3, resulting in generation of mRNA with an insert of 69 nucleotides. In addition, a small amount of a transcript with a deleted exon 3 and a very low level of wild-type transcript were detected. Translation of the extended transcript resulted in an androgen-receptor protein with 23 amino acid residues inserted between the two zinc clusters, displaying defective DNA binding and defective transcription activation.

Androgen-Insensitivity Syndrome↗
PubMed2001

Neither fibroblast growth factor-1 nor fibroblast growth factor-2 is an androgen receptor coactivator in androgen-resistant prostate cancer.

We used rat prostate cancer cell stable transfectants that lacked either endogenous fibroblast growth factor (FGF)-1 secondary to constitutive expression of FGF-1 antisense RNA (aFa2-transfectants) or endogenous FGF-2 isoforms secondary to constitutive expression of FGF-2 antisense RNA (bFa9-transfectants) to examine the potential synergistic effects of mitogen and androgen as modulators of proliferation. During culture on 5% charcoal-stripped fetal bovine serum (CS-FBS), FGF-1 caused a 2- to 2.5-fold increase in the proliferation of aFa2-transfectants that lacked endogenous FGF-1 and retained full expression of FGF-2 isoforms. In marked constrast, bFa9-transfectants that lacked FGF-2 isoforms and retained full expression of FGF-1 died with exponential kinetics when cultured on either 5% CS-FBS or 5% FBS in the absence of FGF-2. However, FGF-2 promoted bFa9-transfectant survival and exponential proliferation during culture on either 5% CS-FBS or 5% FBS. The nonmetabolizable androgen R1881 did not affect proliferation of either the aFa2- transfectants, the bFa9-transfectants, or the parental prostate cancer cells used to generate these transfectants. Additionally, neither of the androgen receptor antagonists RU23908 or bicalutamide affected either FGF-1-mediated aFa2-transfectant proliferation or FGF-2-mediated bFa9-transfectant proliferation during culture on 5% CS-FBS. Notably, transient transfection analyses established R1881 concentration-dependent induction of chloramphenicol acetyltransferase activity in both aFa2-transfectants and bFa9-transfectants. Thus, the failure of either androgen or antiandrogen to affect either FGF-mediated or FGF-independent antisense-transfectant proliferation is not attributable to absence of functional androgen receptors. The results indicate that FGF effects in these androgen-resistant antisense transfectants do not involve either androgen-dependent or androgen-independent, mitogen-mediated androgen receptor activation. Our studies show that these rat prostate cancer cells are characterized by both retention of functional androgen receptors during development of androgen resistance and mitogen-mediated, autocrine or paracrine (or both) modulated proliferation. These are two prominent properties characteristic of advanced human prostate cancer.

Androgen Antagonists↗