Epiphyseal growth and development in mice following administration of a protein-anabolic steroid (17-ethyl-19-nortestosterone).
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Animals↗
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AGR2, an androgen-inducible secretory protein overexpressed in prostate cancer.
AGR2, the human homologue of Xenopus anterior gradient 2 (XAG2), was identified by a suppression subtractive hybridization-based technique as an androgen-inducible gene. There are two AGR2 transcripts, which encode the same secretory protein of 175 amino acids. The androgen induction was time- and dose-dependent, with more than a 10-fold increase in the level of AGR2 mRNA after 48 hr of treatment with 10(-9) M R1881. Expression of AGR2 mRNA was specifically detected in limited human tissue rich in epithelial cells, including the prostate gland. Analysis of 46 microdissected primary prostate adenocarcinoma samples showed that AGR2 mRNA expression was markedly elevated in the majority of tumors as compared to matched adjacent benign tissues. Androgen-induced AGR2 protein expression was demonstrated in LNCaP cells by Western blot analysis with an anti-AGR2 antibody. Immunohistochemistry analysis indicated that AGR2 protein expression was highly restricted to the secretory epithelial cells in the prostate gland. In tissue sections from radical prostatectomy specimens, immunohistochemical staining of AGR2 showed markedly increased expression in high-grade prostatic intraepithelial neoplasia and Gleason pattern 3-4 prostatic adenocarcinoma. Therefore, the androgen-induced secretory protein AGR2 may serve as a potential therapeutic target and/or molecular marker for prostate cancer.
Adenocarcinoma↗
Quantitative expression profile of androgen-regulated genes in prostate cancer cells and identification of prostate-specific genes.
Quantitative expression profile of androgen-regulated genes (ARGs) was evaluated in the hormone-responsive prostate cancer cell line LNCaP by serial analysis of gene expression (SAGE). A total of 83,489 SAGE tags representing 23,448 known genes or expressed sequence tags (ESTs) and 1,655 potentially novel sequences have unraveled the transcriptome of LNCaP cells, the most common cell line used in prostate cancer research. Comparison of transcripts between control and R1881-treated LNCaP cells revealed the induction of 136 genes and repression of 215 genes in response to androgen (p < 0.05). Strikingly, a high fraction ( approximately 90%) of ARGs identified in our study has not been described as ARGs previously. A number of prostate-specific transcription factors were among the ARGs identified here. Classification of the ARGs on the basis of biochemical functions revealed that a great majority of ARGs identified in our experimental system appear to be involved in regulation of transcription, splicing, ribosomal biogenesis, mitogenesis, bioenergetics and redox processes. One of the novel aspects of androgen signaling included androgen regulation of genes involved in DNA repair/recombination process. By comparing our LNCaP-C and LNCaP-T SAGE libraries with SAGE tag libraries available at the NCBI-SAGE website, we have identified >200 potential prostate specific/abundant transcripts. The discovery of new prostate-specific genes and ARGs provides a unique opportunity to determine the role of these genes in prostate cell growth, differentiation and tumorigenesis.
Androgens↗
Clinical use of androgenic steroids at a major medical center: who prescribes androgens and how well do they do it?
To assess prescribing practices for androgens at Wilford Hall USAF Medical Center, the authors analyzed prescriptions for all patients receiving therapy during a 12-month period (n = 201) and reviewed the available outpatient records not maintained elsewhere (n = 105). The most commonly prescribed androgens were testosterone enanthate (144/201; 56.7%), and danazol (52/201; 25.9%). Review of the available outpatient medical records of 73 male patients using testosterone enanthate showed a mean age of 59.5 years, mean frequency of injection of 20 days, mean duration of therapy of 3.5 years, and mean dose of 226 mg. Therapy was initiated by a urologist (34/73; 46.6%), an endocrinologist (33/73; 45.2%), or an internist (6.73; 8.2%). Indications for therapy based on pretreatment laboratory and historical data included hypergonadotropic hypogonadism (24/73; 32.9%), hypogonadotropic hypogonadism (23/73; 31.5%), unspecified hypogonadism (7/73; 9.6%), and empiric treatment of elderly men with erectile dysfunction without evidence of hypogonadism (9/73; 26%). Pretreatment prostate examinations as well as measurement of serum testosterone (66/73; 90.4%) and serum gonadotropins (52/73; 71.2%) were often not performed. The authors conclude that records of patients treated with androgens show: 1) Doses are appropriate; 2) Empiric treatment of erectile dysfunction in elderly men is common despite the associated risks; 3) Laboratory and physical evaluation before treatment is often incomplete; 4) There was no evidence of androgenic substance abuse in patients studied.
Adolescent↗
Evidence for the presence of androgen receptors in purified rat Leydig cells.
Leydig cells, purified on two sequential Percoll gradients to purities of 89 +/- 1%, were used to study the binding of 17-beta-hydroxy-17 alpha-methyl-estra-4,9,11-triene-3-one(3H-R1881). The accumulation of 3H-R1881 in the nuclear fraction of these cells was time- and temperature-dependent. Specific binding was saturable with an apparent Ka of 0.14 nM-1 and a single class of binding sites at a concentration of 721 fmol/mg DNA. A fraction of the bound radioactivity in the nuclear pellet could be extracted with 0.4 M KCl, and a portion of this extracted steroid was associated with macromolecular species. The nuclear accumulation was androgen-specific. These data are consistent with the presence of androgen receptors in rat Leydig cells.
Animals↗
Whole cell and nuclear androgen uptake in skin fibroblasts from infertile men.
In order to reexamine the hypothesis that a high percentage of infertile men with oligo/azoospermia have androgen resistance due to androgen receptor abnormalities, both whole cell and nuclear uptake of [3H]R1881 (a synthetic, nonmetabolizable androgen) were measured in intact, dispersed fibroblasts cultured from pubic skin biopsy specimens of 15 men selected because of infertility associated with varying degrees of oligozoospermia. Eight men had sperm densities less than or equal to 2 X 10(6)/ml; 7 were greater than 2 X 10(6)/ml. Serum levels of FSH and LH were elevated in the severely oligo/azoospermic group, but normal in the other infertile men; concentrations of testosterone, estradiol, and prolactin were normal in both groups. The controls were six normal, age-matched, fertile males. There was no difference in binding capacity or dissociation constant for androgen uptake either into whole cells (3940 +/- 940 [mean +/- SE] sites/cell vs. 4700 +/- 1120 sites/cell, P = NS) or into nuclei (1360 +/- 340 sites/cell vs. 1460 +/- 340 sites/cell, P = NS) of the fibroblasts from the patients vs. the controls, respectively. Furthermore, there was no correlation between patient sperm densities and fibroblast whole cell or nuclear uptake binding capacities. Finally, there was no difference in any androgen binding parameter when only the fibroblasts from the men with severe oligozoospermia or azoospermia were compared with the controls. The authors conclude that the infertility of men with severe testicular germ cell depletion cannot be accounted for by a quantitative androgen receptor abnormality in their pubic skin fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Pharmacokinetics and degree of aromatization rather than total dose of different preparations determine the effects of testosterone: a nonhuman primate study in Macaca fascicularis.
Currently available testosterone (T) preparations differ substantially in their pharmacokinetic profile that might influence their androgenic properties in terms of suppression of the gonadal axis, effects on anabolic parameters, lipid metabolism, and erythropoiesis. The present work was undertaken to determine the physiological effects of three T preparations with different serum kinetics. Twenty adult male cynomolgus monkeys (Macaca fascicularis) were randomly assigned to receive treatment for 28 weeks with either T enanthate (TE) every 4 weeks, T buciclate (TB) every 7 weeks, or T undecanoate (TU) every 10 weeks or remaining untreated (controls). Each injection delivered 20 mg pure T per kilogram body weight. Pharmacokinetic profiles demonstrated higher peak levels of T for TE-treated animals; serum half-lives were longer for TU or TB. Estradiol levels (area under the curve) were significantly higher in TB vs TU or TE. All T regimens suppressed serum luteinizing hormone bioactivity and testicular volumes declined (all P <.001 vs controls). Sperm counts were markedly lowered in all animals but least in TE (P <.01 vs TB or TU). During recovery phase, return to normal for all three parameters occurred significantly earlier in TE-treated animals, followed by those given TU, compared with TB (all P <.001 between groups). Body weight increased significantly during T exposure. This effect was stronger and more sustained in TB vs TU or TE (both P <.001). Serum creatinine and hemoglobin increased with high significance in all T-treated animals (all P <.001 vs controls). The lowering impact of T on serum lipids was markedly stronger in the longer-acting T preparations in comparison with TE, as were effects on purine metabolism (all P <.001). The pattern of exposure and degree of aromatization rather than overall exposure to T determine its effects in the preclinical primate model. Both fluctuations of androgen concentrations and the conversion rate to estradiol influence gonadal suppression as well as metabolism. These results have to be considered in men receiving treatment for hypogonadism or regimens for hormonal contraception.
Animals↗
Replacement of surgical castration by GnRH inhibition for rat prostate androgen receptor preparations.
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Androgen Antagonists↗
Prodrugs utilizing organosilyl derivation: an investigation of the long-term androgenic and myotrophic activities of silyl derivatives of testosterone.
The long-term androgenic and myotrophic activities of dimethylditestosteroxysilane and diphenylditestosteroxysilane were studied and compared with the activities of testosterone propionate and testosteroxytrimethylsilane. The testing was carried out in vivo, using castrated male rats, over a 50-d period. Dimethylditestosteroxysilane and diphenylditestosteroxysilane were shown to exhibit both myotrophic activity and androgenic activity. In the early stages of the study, dimethylditestosteroxysilane displayed myotrophic activity with no corresponding androgenic activity. The results presented indicate that these silyl ethers act as latentiated derivatives of testosterone.
Animals↗
Responsiveness to endocrine manipulations in breast cancer after "prophylactic" castration.
Two hundred and one cases of premenopausal women with breast cancer who underwent prophylactic castration with subsequent recurrence were review to ascertain the degree of responsiveness of these patients to subsequent endocrine manipulation. We show that the standard endocrine manipulations, particularly the major ablations, retain a fair degree of activity in this group. There is a suggestion that the longer the castration-recurrence interval, the higher the chance of a response, but the difference is significant only for osseous-dominant disease. As in other patient groups, responders to subsequent endocrine manipulations live longer than nonresponders.
Adrenal Cortex Hormones↗
Growth inhibition and differentiation in human prostate carcinoma cells induced by the vitamin D analog 1alpha,24-dihydroxyvitamin D2.
BACKGROUND: Vitamin D has been suggested as a chemopreventive and therapeutic modality for prostate cancer. However, hypercalcemic toxicity has limited the use of 1alpha,25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)) in clinical trials, prompting the search for analogs of vitamin D with less toxicity while retaining efficacy as a modality for cancer intervention. In this study, the less hypercalcemic vitamin D analog 1alpha,24-dihydroxyvitamin D(2) (1,24-(OH)(2)D(2)) was examined for its effects on cellular growth inhibition and differentiation induction in the LNCaP human prostate carcinoma cell line. METHODS: LNCaP cell growth was determined by quantifying DNA levels. Protein levels were determined using the ELISA method and immunoblotting. Levels of mRNA were determined using real-time quantitative reverse transcriptase PCR. RESULTS: LNCaP growth was decreased 50% by exposure to 0.01 nM 1,24-(OH)(2)D(2) after 96 hr in the presence of a growth stimulatory 0.1 nM dose of the androgen R1881. Prostate specific antigen (PSA) levels were increased 3.5-fold with 10 nM 1,24-(OH)(2)D(2) treatment compared to a 1.9-fold increase in PSA levels found with 10 nM 1,25-(OH)(2)D(3) under low androgen conditions. Neither 1,24-(OH)(2)D(2) nor 1,25-(OH)(2)D(3) affected the expression of cytokeratin 18 protein levels. Treatment with 10 nM 1,24-(OH)(2)D(2) alone produced a 1.3-fold increase in AR mRNA and a 2.2-fold increase in AR protein levels after 96 hr. Surprisingly, the addition of 1.0 nM R1881 alone or in combination with 10 nM 1,24-(OH)(2)D(2) produced an approximately 60% decrease in AR mRNA, whereas AR protein levels were increased 1.6-fold. CONCLUSIONS: Overall, 1,24-(OH)(2)D(2) was found to be at least as effective as 1,25-(OH)(2)D(3) at inhibiting growth and inducing differentiation markers in LNCaP prostate carcinoma cells and may thus prove useful in prostate cancer treatment.
Blotting, Western↗
Relaxin becomes upregulated during prostate cancer progression to androgen independence and is negatively regulated by androgens.
BACKGROUND: Relaxin is a potent peptide hormone normally secreted by the prostate. This study characterized relaxin expression during prostate cancer progression to androgen independence (AI), and in response to androgens. METHODS: The prostate cancer cell line, LNCaP, was assayed by microarrays and confirmatory Northern analysis to assess changes in relaxin levels due to androgen treatment and in LNCaP xenografts following castration. Relaxin protein levels were examined by immunohistochemistry (IHC) in tissue microarrays of human prostate cancer samples following androgen ablation. RESULTS: Relaxin levels decreased in a time and concentration-dependent manner due to androgens in vitro, and increased in xenografts post-castration. Relaxin increased in radical prostatectomy specimens after 6 months of androgen ablation and in AI tumors, was highest in bone metastases. CONCLUSIONS: Relaxin is negatively regulated by androgens in vitro and in vivo, which correlates to clinical prostate cancer specimens following androgen ablation. The role of relaxin in angiogenesis and tissue remodeling suggests it may contribute to prostate cancer progression.
Animals↗
Influence of prostatic secretion protein on uptake of androgen-receptor complex in prostatic cell nuclei.
Prostatic secretion protein (PSP) is a major component of rat prostatic cytosol, and this protein is also found in the prostatic fluid. Purified PSP was found to inhibit the nuclear uptake of the [3H]methyltrienolone-receptor complex in vitro. Furthermore, purified PSP inhibited the binding of this androgen-receptor complex to DNA-cellulose. It is suggested that these effects of PSP may represent an intracellular control system regulating the concentration of PSP. Administration of estramustine, the dephosphorylated metabolite of the anti-cancer drug estramustine phosphate (Estracyt), to rats was found to decrease the weight of the prostate gland but to maintain the concentration of PSP, calculated as mg PSP/mg protein, at a constant level. In contrast, castration or administration of estradiol-17 beta valerate decreased the weight of the prostate gland as well as the concentration of PSP. These findings indicate that the mechanism of action of estramustine is at least partially different from that of estradiol-17 beta. Furthermore, it is suggested that estramustine may exert part of its action through its effects on the concentration of PSP.
Animals↗
Androgen receptor binding characteristics in the cytosol of the rat dorsolateral prostate gland and the Dunning R-3327 prostatic adenocarcinoma.
The incidence of prostatic cancer is highly correlated with advanced age, and it has been suggested that changes in androgen binding may be important in age-associated alterations in growth regulatory mechanisms of prostatic epithelial cells. In this study the effects of age on androgen binding characteristics in the dorsolateral prostate glands of young and aged Copenhagen rats were determined and the binding properties in the Dunning R3327/130 subline of rat prostatic adenocarcinoma were characterized. Tritium-labeled and nonlabeled methyltrienolone analogs (R1881) were used to study the binding properties of 5 alpha-dihydrotestosterone receptor in the cytosol of tumors and prostate glands. Binding of R1881 was low but specific for the androgen receptor as shown by competition studies in which nonlabeled R1881, 5 alpha-dihydrotestosterone, and testosterone competed successfully with 3H-R1881 for binding sites, but 17 beta-estradiol and low levels of progesterone did not. In Copenhagen dorsolateral prostate, Scatchard analysis suggested a single class of binding sites. In young animals (three to five months) the average binding capacity was 10.36 fmol/mg cytosol protein with a dissociation constant (Kd) of 2.28 nmol/L. The dorsolateral prostate of aged rats (11-16 months) showed no significant difference in specific binding characteristics as compared to the younger age group. Specific binding of 3H-R1881 in R3327/130 tumor was saturable with a single class of high-affinity binding sites having an average binding capacity of 64.77 fmol/mg cytosol protein and a Kd of 2.76 nmol/L. These data show that the tumor had approximately 6.5 times the number of binding sites as did the normal Copenhagen rat dorsolateral prostate gland. However, no age-related changes were detected through 11-16 months of age in the androgen binding characteristics of normal rat dorsolateral prostate gland that could be correlated with the higher concentration of androgen binding sites in the R3327/130 tumor subline.
Adenocarcinoma↗
Fluorescent androgen derivatives do not discriminate between androgen receptor-positive and -negative human tumor cell lines.
For the evaluation of histochemical procedures for detection of androgen receptors, three human tumor cell lines have been used: PC-93 and NHIK-3025, both biochemically characterized as androgen receptor-positive, and EB-33, biochemically characterized as androgen receptor-negative. The binding of three fluorescent ligands, testosterone-17 beta-hemisuccinate-bovine serum albumin-fluorescein isothiocyanate, testosterone-17 beta-hemisuccinate-fluoresceinamine, and 5 alpha-dihydrotestosterone-17 beta-hemisuccinate-fluoresceinamine, to the cells was evaluated. The relative binding affinities of the ligands for the androgen receptors were low (less than 5% when compared to methyltrienolone). Treatment of the cells with the androgen-fluoresceinamine derivatives resulted in a fluorescent labeling of the cytoplasm in both intact and "freeze-damaged" cells of the three cell lines. This staining was independent of the presence of receptors. Nuclei were not stained. Incubation of intact cels with the protein-linked conjugate did not result in significant cellular fluorescence. Only cells with damaged membranes showed a positive histochemical reaction, both in nucleus and cytoplasm, irrespective of the receptor content of the cells. The fluorescence intensity was not suppressed with excess 5 alpha-dihydrotestosterone or methyltrienolone, which are known to prevent binding of low affinity ligands to androgen receptors. From these results it is concluded that androgen receptors cannot be detected by these fluorescent ligands with low affinity for the receptor. The observed fluorescence of the cells is therefore due to binding of the ligands to other binding sites. The visualization/histochemical demonstration of these binding sites does not appear to be related to the presence of androgen receptors.
Adenocarcinoma↗
Clinical applications and value of receptor levels in treatment of prostate cancer.
Factors affecting the validity and interpretation of androgen receptor (AR) assays on prostatic carcinoma tissue are discussed, and attempts to relate AR concentration with response of the patient to hormonal manipulation are reviewed. It is concluded that nuclear AR content may be useful in evaluating prognosis and likely response to hormonal therapy, and that, owing to the heterogeneity of many prostatic carcinoma specimens, a reliable histochemical method for the assessment of androgen sensitivity would be a valuable supplement to the biochemical assay.
Androgens↗
Single case report of prostate adenocarcinoma in a dog castrated three months previously. Morphological, biochemical, and endocrine determinations.
During the course of another investigation, three dogs had been castrated 3 months previously. Upon completion of the experiment, it was discovered that one dog presented a spontaneous prostatic adenocarcinoma of intraalveolar proliferative type at histology. Prostate weight of this dog before castration was estimated to be 22 g by tridimensional measurement at laparotomy and remained relatively constant (19 g) 3 months after castration. These results indicate that if regression had occurred in some cell populations (androgen-dependent) it was only partial and masked by growth of androgen-independent cells. Analysis of 12 individual steroids in peripheral blood and in prostatic tissue attested of a normal adrenal secretory activity. A series of 15 hydrolytic enzymes along with receptors for androgen, estrogen, and progesterone, were determined in prostatic tissue obtained at sacrifice. Enzymatic activities were those of typical epithelial cells, and most of them remained relatively high despite low levels of circulating testosterone. However, two markers of androgen action in dog prostate, acid phosphatase and arginine esterase, were significantly reduced. Receptor levels were similar to those of castrated animals. Thus, cancer cells had probably retained some androgen sensitivity.
Adenocarcinoma↗
The use of radioactive 7 alpha, 17 alpha-dimethyl-19-nortestosterone (mibolerone) in the assay of androgen receptors.
Tritiated 7 alpha, 17 alpha-dimethyl-19-nortestosterone (DMNT; mibolerone), a synthetic androgen stable to metabolic conversion in the rat ventral prostate, is an excellent radioactive ligand for the quantitation and characterization of androgen receptors in prostate, liver, and cultured cells. DMNT is more receptor-selective than 17 alpha-methyl-17 beta-hydroxy-estra-4,9,11-trien-3-one (R1881); DMNT interacts with glucocorticoid and progestin receptors much less strongly than R1881. Unlike 5 alpha-dihydrotestosterone, DMNT does not bind tightly to testosterone-estradiol binding globulin of human serum. The hydroxylapatite-filter assay we employed can clearly distinguish between DMNT binding to androgen receptors of rat ventral prostate and interaction of DMNT with androgen binding protein of epididymides. The prostate cytosol (3H)DMNT-receptor complex sediments in two forms (4 and 8 S) in a low salt medium. In 0.4 M KCl, both the prostate cytosol and nuclear (3H)DMNT-receptor complexes migrated as 3-4 S components. The formation of both the cytosol and nuclear DMNT-receptor complexes is inhibited by antiandrogens and 17 beta-estradiol.
Androgen-Binding Protein↗