This Article Abstract Full Text (PDF) All Versions of this Article: 91/10/3850    most recent Author Manuscript (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Page, S. T. Articles by Bremner, W. J. Search for Related Content PubMed PubMed Citation Articles by Page, S. T. Articles by Bremner, W. J. Related Collections Male Endocrinology

Persistent Intraprostatic Androgen Concentrations after Medical Castration in Healthy Men

Departments of Medicine (S.T.P., E.A.M., J.K.A., P.S.N., A.M.M., W.J.B.), Urology (D.W.L.), and Pathology (L.D.T.), University of Washington School of Medicine, Seattle, Washington 98195; Veterans Affairs Puget Sound Health Care System (S.T.P., D.W.L., A.M.M.), and Geriatric Research, Education and Clinical Center (A.M.M.), Seattle, Washington 98108; Oregon National Primate Research Center (D.L.H.), Oregon Health & Science University West Campus, Beaverton, Oregon 97006; and Divisions of Human Biology and Clinical Research (P.S.N.), Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024

Address all correspondence and requests for reprints to: Stephanie T. Page, University of Washington Medical Center, Division of Metabolism, Endocrinology and Nutrition, Box 357138, 1959 NE Pacific, Seattle, Washington 98195. E-mail: page{at}u.washington.edu.

	Abstract

Top Abstract Introduction Subjects and Methods Results Discussion References

 
Context: The impact of serum androgen manipulation on prostate tissue hormone levels in normal men is unknown. Studies of men with prostate cancer have suggested that prostatic androgens are preserved in the setting of castration. Tissue androgens might stimulate prostate growth, producing adverse clinical consequences.

Objective: The objective of the study was to determine the effect of serum androgen manipulation on intraprostatic androgens in normal men.

Design: Thirteen male volunteers ages 35–55 yr (prostate-specific antigen < 2.0 ng/ml; normal transrectal ultrasound) were randomly assigned to: 1) a long-acting GnRH-antagonist, acyline, every 2 wk; 2) acyline plus testosterone (T) gel (10 mg/d); or 3) placebo for 28 d. Serum hormones were assessed weekly. Prostate biopsies were obtained on d 28. Extracted androgens were measured by RIA, and immunohistochemistry for androgen-regulated proteins was performed.

Results: The mean decrease in serum T was 94%, whereas prostatic T and dihydrotestosterone levels were 70 and 80% lower, respectively, in subjects receiving acyline alone compared with controls (P < 0.05). Despite this decrease in prostate androgens, there were no detectable differences in prostate epithelial proliferation, apoptosis, prostate-specific antigen, and androgen receptor expression.

Conclusion: In this small study of healthy subjects, despite a 94% decrease in serum T with medical castration, intraprostatic T and dihydrotestosterone levels remained 20–30% of control values, and prostate cell proliferation, apoptosis, and androgen-regulated protein expression were unaffected. Our data highlight the importance of assessing tissue hormone levels. The source of persistent prostate androgens associated with medical castration and their potential role in supporting prostate metabolism deserves further study.

	Introduction

Top Abstract Introduction Subjects and Methods Results Discussion References

 
THE PROSTATE IS an androgen-sensitive organ. Normal prostate development is androgen-dependent, requiring not only testosterone (T) but also the activity of the 5-reductase enzymes, which convert T to the more potent androgen dihydrotestosterone (DHT). In hypogonadal men, androgen replacement that raises serum T levels increases prostate size to age-appropriate levels. The prostate expresses high levels of type II 5-reductase (1, 2) and enzymes involved in steroid metabolism (3, 4); therefore the endocrine milieu within the prostate may substantially differ from that of serum. For example, treatment with a 5-reductase inhibitor minimally impacts serum T, yet results in substantial reduction in intraprostatic DHT with concomitant increases in intraprostatic T (5, 6, 7). Data regarding the relationship between serum and prostate tissue hormone levels in normal men are lacking.

Previous analyses of prostate tissue hormone levels obtained at the time of autopsy or organ donation have demonstrated that DHT is the dominant androgen in the human prostate, consistent with the high levels of intraprostatic 5-reductase (3, 8, 9). In these studies, however, serum steroid levels were not available for comparison and may have been significantly affected by end-of-life physiological stresses, as they are with surgery or prostate or other disease states (10, 11). Reports of prostate hormone levels in surgical specimens from patients with prostate cancer or benign prostatic hypertrophy (BPH) have been conflicting regarding the effect of serum hormone manipulation on intraprostatic androgen concentrations (12, 13, 14, 15, 16). GnRH agonist treatment associated with castrate serum T levels results in a 75–80% decrease in prostatic T and DHT levels in BPH patients (16). In contrast, Mohler et al. (15) reported that despite prolonged castration treatments, intraprostatic T levels in hormone refractory prostate cancer were normal, whereas intraprostatic DHT levels were reduced by 75%. In addition, inhibition of 5-reductase results in a significant decrease in intraprostatic DHT and increased prostate T, without impacting serum T levels (7, 17). Together, these results demonstrate that serum androgen concentrations do not reflect those in the prostate gland in disease states or postmortem and suggest that manipulation of serum androgens may not alter target tissue androgens in an equivalent manner. It is unclear from these reports, however, whether this difference is due to prostate diseases or whether these differences are present in healthy men.

We hypothesized that experimentally induced decreases in serum androgens in normal, middle-aged men would result in decreases in intraprostatic androgens and that this change in the androgenic milieu would alter prostate epithelial cell apoptosis and expression of androgen-regulated proteins. We performed a randomized, single-blind study of 12 healthy men to determine the effect of serum androgen deprivation and replacement on tissue androgen levels within the normal prostate. Tissue hormone levels were measured in prostate core biopsies obtained using a standard office prostate biopsy procedure to minimize the possible impact of operative medications and surgical stress on hormone measurements.

	Subjects and Methods

Top Abstract Introduction Subjects and Methods Results Discussion References

 
Acyline

Acyline is a 10-amino acid peptide that acts as a GnRH antagonist (18). Acyline lyophilized powder synthesized by NeoMDS (San Diego, CA) was suspended in bacteriostatic water at 2 mg/ml and administered by sc injection in the abdomen. This dose has been previously demonstrated to render subjects medically castrate (T < 1.7 nmol/liter) within 24 h, with maintenance of castrate T levels for 2 wk (19).

Subjects

All procedures involving human subjects were approved by the Institutional Review Board at the University of Washington and performed in accordance with the guidelines in the Declaration of Helsinki. Of 14 men (ages 35–55 yr) recruited by advertisement, 13 met study criteria, including: normal medical histories; taking no medications; normal baseline physical examinations including prostate size by digital rectal exam and transrectal ultrasound; normal serum chemistries, complete blood count, gonadotropins, and T; and a prostate-specific antigen (PSA) of less than 2.0 ng/ml. One man was lost to follow-up after the first study visit and was not included in the analyses.

Protocol

After screening, subjects were randomly assigned to one of three treatment groups (n = 4 per group): 1) placebo vehicle injections sc plus placebo gel daily; 2) sc acyline 300 µg/kg d 0 and 14 plus placebo gel daily (acyline only); or 3) sc acyline 300 µg/kg d 0 and 14 plus T gel, 100 mg topically daily (Testim 1%, Auxilium Pharmaceuticals, Norristown, PA) (acyline+T). Blood was collected at baseline (d 0), weekly during treatment, and 1 month after drug exposure (recovery, d 56) for hormone analyses as well as biweekly for PSA. Transrectal ultrasound to measure prostate size was performed on d 0, 28, and 56 by the same operator to minimize operator-dependent error. On d 28, prostate tissue was obtained by laterally directed, transrectal ultrasound-guided biopsies of the peripheral zone after administration of local anesthesia (1% lidocaine). Two biopsies were obtained from each sextant for a total of 12 cores, each weighing 5–10 mg. For tissue hormone measurements, individual biopsies were immediately snap-frozen in liquid nitrogen. For immunohistochemistry, individual biopsies were immediately embedded in Optimal Cutting Temperature compound (Tissue-Tek, Pelco International, Redding, CA) and snap-frozen in isopentane precooled in liquid nitrogen. All samples were stored at –80 C. A study pathologist (L.D.T.) reviewed at least two biopsies from each subject. No evidence of malignancy or prostatic epithelial neoplasia was found in any case.

Measurements

Serum and tissue T and DHT. Prostate and serum androgens T and DHT were measured as described previously (20). In brief, thawed tissues were individually homogenized with an 8-mm probe at 4 C. Each homogenate was decanted to an extraction tube, the homogenization tube and probe were washed three times with diethyl ether, and the washes were transferred to the extraction tube. All samples were extracted by repeated inversion of the tubes, and the organic and aqueous phases were separated by centrifugation at 2500 rpm; the aqueous phase was frozen in a dry ice/ethanol bath, the ether was decanted and dried, and the extract was stored in ethanol until chromatography. Serum samples were similarly extracted in diethyl ether at 4 C. All extracted samples were subjected to chromatography on Sephadex LH-20 microcolumns to isolate T and DHT (and androstenedione for serum). The ether extract from each sample was applied to individual 1.0 g Sephadex LH-20 columns, and the estradiol and neutral fractions were collected using hexane:benzene:methanol (62:20:13) for elution as previously described (20). The neutral fractions were chromatographed on individual 2.5 g Sephadex LH-20 columns, and individual androgen fractions were collected using hexane:benzene:methanol (85:15:5) as the application and eluting solvent. Steroid concentrations of the appropriate fractions were estimated by RIA (21). Estimation of steroid losses during extraction and chromatography were monitored by recovery of added H³T, C¹⁴ DHT (and H³ androstenedione for serum, approximately 8000 cpm each) to equivalent weights of prostate tissue obtained from healthy individuals undergoing transurethral resection of the prostate or to equivalent volumes of control serum. The average percentage recovery for T, DHT, and androstenedione for both serum and tissue was 73.5, 69.7, and 75.2%, respectively. Six prostate core biopsies, one from each sextant, were analyzed per subject, and reported measurements average all values per tissue weight after correction for recovery and blank values. The lower limit of detection for each hormone in tissue was 0.38 ng/g. The intraassay coefficients of variation (CVs) were 7.9, 12.9, and 14%, respectively. All samples were measured in a single assay for each hormone.

Serum dehydroepiandrosterone (DHEA), DHEA sulfate (DHEA-S), and estradiol

Serum DHEA and DHEA-S were measured by RIA (Diagnostic Systems Laboratories, Webster, TX). Intraassay CVs for mid- and high-range values were 7.8 and 6.3% for DHEA and 10.6 and 7.3% for DHEA-S. Interassay CVs were 10.0% for DHEA and 7.8% for DHEA-S. Serum estradiol was assessed using a Roche Diagnostics Elecsys 2010 clinical assay instrument. Sensitivity was 18.3 pmol/liter, and intraassay CVs were 3.7 and 2.8% for mid- and high-range values, whereas the interassay CVs were 4.7%. The normal range for serum estradiol in this assay in men was 40–220 pmol/liter. All samples were run in the same assay.

Serum gonadotropins. FSH and LH levels were measured by immunofluorometric assay (Delfia, Turku, Finland). Samples from a given individual were measured in a single assay. The sensitivity of the assay for FSH and LH was 0.016 and 0.019 IU/liter, respectively. For low-, mid-, and high-pooled values of 0.054, 1.04, and 20.8 IU/liter of FSH, the intraassay CVs were 12, 1.9, and 2.9%, and the interassay CVs were 18, 6.1, and 4.1%, respectively. For low-, mid-, and high-pooled values of 0.056, 0.95, and 15.6 IU/liter of LH, the intraassay CVs were 6.5, 3.9, and 5.4%, and the interassay CVs were 21, 8, and 6.6%.

Clinical chemistries and PSA. Screening and monitoring labs for PSA, complete blood count, electrolytes and glucose (chemistry 7), calcium, and liver function tests were measured by the Department of Laboratory Medicine, University of Washington. PSA was assessed using a Hybridtech Enzyme Immunoassay. Inter- and intraassay CVs for this assay are 2–4%.

Immunohistochemistry

Five-micron frozen tissue sections were stained for the following antigens using a three-step indirect avidin-biotin immunoperoxidase method: Ki-67 (monoclonal MIB-1, Dako Inc., Carpinteria, CA), a marker of cell proliferation; PSA (polyclonal, Dako Inc.); androgen receptor (AR) (monoclonal F36.4.1, BioGenex, San Ramon, CA); and caspase-3 (monoclonal 9661, Cell Signaling Technology, Inc., Danvers, MA), a marker of apoptosis. Specificity of labeling was confirmed by omission of the primary antibody. All sections for the entire study were prepared in a single batch for each stain. Ki-67 index was calculated as the number of positively staining nuclei divided by the total gland area for that cross-section; at least five glands were tabulated for each subject. For PSA, AR, and caspase-3, analyses were performed using Image Pro-Plus version 4.2 software (Media Cybernetics, Silver Spring, MD). All images for analyses were made at 40x with the same light intensity and color thresholding for all sections for each stain. The percentage of total epithelial (for PSA and caspase-3) or nuclear (for AR) area positively stained in a minimum of five glands and/or 500 epithelial cells was assessed. Successive tabulations were accumulated until the marginal change in the coefficient of variation of the running mean value (for the percentage area positively stained) was less than 5% (22).

Statistical analysis

Hormone measurement data were log-transformed before analysis. For differences between groups, data were compared by ANOVA with a Scheffé post hoc correction for multiple comparisons. For within-group comparisons to baseline, paired t tests were performed with a Bonferroni correction for multiple comparisons. Pearson correlations were performed to examine the relationship between serum and intraprostatic hormone concentrations. P values < 0.05 were considered statistically significant. Statistical analyses were performed using STATA version 8.0 (Stata Corp., College Park, TX).

	Results

Top Abstract Introduction Subjects and Methods Results Discussion References

 
Study population

The baseline characteristics of the study subjects are given in Table 1. The subjects randomized to the placebo group were older, with greater average prostate volumes at baseline. There were no significant differences between baseline hormone values between groups, with the exception of slightly lower LH levels in the acyline+T group.

Serum gonadotropins

LH and FSH declined in both groups receiving the GnRH antagonist, acyline, during treatment and were unchanged in the placebo group (Table 2). In both groups treated with acyline, there was a significant decrease in LH compared with baseline and placebo with treatment (P < 0.05 for both comparisons). Similarly, FSH was significantly lower in both the acyline-treated groups compared with both placebo and baseline and was lower in the acyline+T group compared with acyline alone (P < 0.05).

In the subjects receiving acyline alone, serum T and DHT declined significantly, compared with both baseline and the placebo and acyline+T groups, at all time points during the drug exposure period (P < 0.05) (Table 2 and Ref. 23). In the acyline-only group, serum T concentrations during treatment were near or below castrate levels (T < 1.7 nmol/liter) throughout the 28 d of treatment (23). There were no significant differences in serum T between the placebo and acyline+T groups at any time point, nor within these groups compared with baseline; therefore T supplementation maintained physiological T levels in men receiving acyline+T. Serum DHT levels were slightly increased in subjects receiving acyline+T compared with the placebo group on d 7 and 21 (23), but this difference was not significant on d 28 or at recovery.

Serum estradiol declined by approximately 50% in the subjects receiving acyline compared with baseline and with the acyline+T group throughout the drug exposure period (P < 0.05) (Table 2). Serum SHBG, androstenedione, DHEA, and DHEA-S were unchanged in all three groups throughout the treatment and recovery periods, and no differences were noted between the groups.

Prostate tissue androgens

Prostate tissue T and DHT measured on d 28 of treatment were significantly lower in subjects receiving acyline alone compared with the other two groups (P < 0.05) (Fig. 1). Subjects receiving acyline alone had prostate T levels approximately 70% lower than the placebo group and 60% lower than subjects treated with acyline+T (Fig. 1A). Prostate DHT levels were similarly lower in subjects receiving acyline alone, reduced by approximately 80 and 70% compared with levels in subjects receiving placebo or acyline+T, respectively (Fig. 1B). There were no significant differences in prostate tissue androgens between the two control groups (placebo and acyline+T). The ratio of intraprostatic DHT:T was 5.0, 3.5, and 4.9 for placebo, acyline, and acyline+T, respectively.

View larger version (12K): [in this window] [in a new window]   FIG. 1. Comparison of prostate and serum androgen levels. Serum androgens (nanograms per milliliter in black) on d 28 and prostate androgens (nanograms per gram in white) are compared. *, P < 0.05 vs. baseline. Error bars are ± SEM.

In the placebo group, the ratio of prostate to serum T levels was 0.5 (Fig. 1A), whereas DHT was the dominant androgen in the prostate, 22-fold more concentrated in tissue than serum in subjects in the placebo group (Fig. 1B). With acyline treatment, both serum and prostate T and DHT were lower, but the relative ratio of T in the prostate vs. serum increased to 2, whereas the ratio of DHT in prostate to serum was comparable to the placebo group (19 compared with 22). The acyline+T group maintained tissue:serum T levels in the same range as the placebo group, and, due to an increase in serum DHT, had a relative decrease in the ratio of tissue:serum DHT levels to 5.

We examined the association between serum and prostate tissue androgens in all three groups. When all three groups were considered, there was a significant correlation between serum T and prostate androgens (r = 0.79 for serum T vs. prostate T, P = 0.002; and r = 0.81 for serum T vs. prostate DHT, P = 0.001). In contrast, there was no significant correlation between serum DHT (r = 0.5 for serum DHT vs. prostate T, P = 0.1; r = 0.5 for serum DHT vs. prostate DHT, P = 0.08), DHEA, DHEA-S, or androstenedione (data not shown) and prostate tissue androgens.

Limiting the analyses to the medically castrate group (acyline alone), there was no correlation between serum T and DHT and prostate tissue androgen levels (data not shown).

However, when we examined the relationship between adrenal androgens in the medically castrate subjects, there was a strong positive correlation between serum DHEA and prostate androgen levels (r = 0.94 for prostate T, P = 0.06; and r = 0.99 for prostate DHT, P = 0.006).

Serum PSA and prostate volume

Serum PSA was significantly reduced by d 28 of treatment compared with baseline only in those subjects receiving acyline alone (Table 2), and serum PSA recovered to baseline levels 1 month after cessation of drug. The PSA differences between groups were not significant. There were no significant differences in prostate volume between the groups, and prostate volume was maintained in all groups throughout the study.

Prostate immunohistochemistry

Because androgens play a role in prostate growth, we evaluated prostate epithelial cell turnover in our study biopsies. Neither Ki-67 index, a measure of prostate epithelial cell division that is hormone sensitive (24), nor caspase-3 expression (as a measure of apoptosis) (25, 26, 27), was significantly different between subjects receiving acyline and the control groups (Table 3). We found no detectable difference in the cellular area of PSA or AR immunostaining [two genes known to be androgen-regulated (28, 29)] between the medically castrate group and the control subjects (Table 3).

	Discussion

Top Abstract Introduction Subjects and Methods Results Discussion References

Despite a markedly lower level of prostate androgens in subjects treated with acyline for 1 month compared with placebo (Fig. 1), tissue DHT and T were still easily detected in the acyline-alone group. In fact, the absolute level of prostate DHT in the medically castrate group remained remarkably high (1.9 ng/g), approximately 20-fold higher than serum DHT (0.1 ng/ml, Fig. 1B) and comparable to levels of serum T in intact men (3.6 ng/ml, Fig. 1A). Similar levels of DHT have been found in other studies of longer-term medical castration for prostate cancer (14, 31). Because DHT is thought to be 10-fold more potent than T (32), this level of prostate DHT may have significant biological activity. Our immunohistochemistry results support this hypothesis because there were no detectable changes in prostate epithelial cell proliferation (Ki-67 labeling index), PSA and AR expression, or apoptosis after 1 month of androgen deprivation in normal men. These findings suggest that the level of prostate tissue androgens preserved, albeit significantly lower levels than controls, in these medically castrate men might be sufficient to support several biological processes within the normal prostate. Our data demonstrate that serum and tissue hormone manipulations may not be equivalent in healthy subjects, and suggest that examination of tissue hormone levels may be an important endpoint in understanding human physiology.

Our tissue hormone results are similar to those measured after prostatectomy in men with BPH treated for 3 months with a GnRH agonist (12). However, they are in contrast to recent observations by Mohler et al. (15) who found a preservation of prostate T concentrations in hormone-refractory prostate cancer despite a minimum of 6 months of medical or surgical castration. The reason for the discrepancy between the effects of castration on intraprostatic T concentrations reported here and those of Mohler et al. (15) is not known but may be a function of evaluating different tissue types (normal vs. androgen independent prostate cancer) or the duration of treatment.

The source of prostate androgens in the setting of medical castration is not clear from our study. Although it is possible that intraprostatic androgens arise from residual testicular-derived serum androgens, the prostate has been shown to express, at least at the transcript level, all the enzymatic machinery required to convert adrenal precursors such as androstenedione, DHEA, and DHEA-S to DHT (3, 4), and increased expression of enzymes involved in androgen metabolism has recently been demonstrated in androgen-independent prostate cancer (29). The hypothesis that adrenal androgens become an important source of prostate androgen precursors in the setting of low serum T associated with medical castration is supported by our observation that there is a strong correlation between serum DHEA (but not T or DHT) and prostate tissue hormone levels among subjects receiving acyline alone (albeit in a small number of subjects). The effectiveness of "androgen ablation" therapy in the treatment of hormone-sensitive disease relies upon the achievement of low serum T levels as a clinical endpoint. If non-gonadotropin-dependent androgens can arise from the conversion from adrenal precursors within the prostate gland itself, the achievement of castrate serum androgen levels may be insufficient for true androgen ablation within the prostate and may contribute to the emergence of recurrent disease. The possible relationship between adrenal and intraprostatic androgens in the setting of medical castration should be further examined in a greater number of subjects to confirm these suggestive findings. Determining the source and clinical impact of remaining tissue androgens after longer-term medical castration will require further study.

The absolute levels of intraprostatic androgens measured in our study are somewhat higher than those reported by others in prostate cancer and BPH (5, 7, 16, 30), but are consistent with early results in normal prostate from Geller et al. (33) and may be related to our sampling of younger men who may have higher intraprostatic androgens (34). This may be attributable to our use of flash-frozen needle biopsy material. The needle biopsy procedure, unlike autopsy studies and specimens collected during surgery, does not entail warm ischemia time, which has been shown to result in significant decrements in intraprostatic DHT (30). The same is likely true for T, given the high concentration of intraprostatic 5-reductase. Nor does our method require the use of general anesthesia or occur after significant stress associated with end of life, both of which have been associated with significant reductions in serum androgens (10). In addition, the average age of our subjects was lower than those enrolled in previous studies, and it has been suggested that tissue androgens, like those in serum, may fall with age (34).

Our study has some limitations. The number of subjects per group is small. Other studies with more subjects have examined men who were undergoing prostate biopsy for cause (i.e. symptoms, rising PSA); thus our data are unique in studying normal, healthy volunteers. However, due to the small sample size, we may have missed small differences between groups in epithelial cell turnover and androgen-regulated protein expression. Our results may be impacted by the length of treatment. Although the half-life of serum T is in the order of hours (35), the half-life of tissue androgens is not known, and it is possible that longer periods of androgen ablation are required to see changes in prostate epithelial cell proliferation or apoptosis. Very small but detectable changes in total and transitional zone volume have been observed with treatment using a potent 5-reductase inhibitor as soon as 1 month in a very large cohort (36), although a previous small study of a GnRH agonist failed to detect changes in prostate size at 1 month (37). Interestingly, we observed a decrease in serum PSA (Table 2) in the acyline-treated subjects, whereas there was no difference in prostate tissue PSA staining (Table 3). We are not the first to observe a lack of correlation between serum and tissue PSA levels (24, 38). It will be important in future studies to determine whether these factors change with a longer treatment period. On the other hand, our period of observation may have been too long, because prostate cells may be able to adapt to changes in androgen concentration by regulation of downstream effectors. For example, Bozec et al. (39) reported that caspase-3 expression increased after 3 d of finasteride treatment, however it returned to baseline after 30 d of treatment. Similarly, Ohlson et al. (40) recently demonstrated that in both neoplastic and adjacent normal prostate epithelium, maximum increases in apoptosis and suppression of proliferation occurred 3 d after castration, yet returned to baseline by 8–10 d after castration. Future studies examining the impact of serum androgen manipulation on tissue hormone concentration over time are warranted. It is also possible that although we achieved castrate serum T levels, the degree of gonadotropin and testicular suppression was not adequate to reduce maximally prostate androgens. Finally, in an effort to limit the morbidity associated with the study procedures, biopsies were limited to the prostate peripheral zone, the area where the majority of prostate cancers arise. Some investigators have found differences in prostate androgen concentrations among different zones (peripheral vs. transitional zones) of the prostate in subjects with BPH (41); it is possible that we may have missed regional differences in prostatic androgen concentrations.

In conclusion, in this randomized, controlled trial we determined the level of prostate T and DHT in the normal, human prostate as well as the effect of GnRH antagonist treatment for 1 month on intraprostatic androgens. The ratio of DHT:T within the prostate is preserved in the setting of medical castration. Despite more than 90% suppression of serum androgens, intraprostatic T and, to a lesser extent, DHT are not suppressed to the same degree after 1 month of acyline treatment. Levels of the potent androgen DHT within the prostate gland after 1 month of medical castration may continue to support androgen-dependent protein expression because we observed no differences in prostate epithelial cell proliferation, apoptosis, PSA, or AR expression after 1 month of acyline treatment. These findings highlight the importance of assessing tissue hormone levels in understanding prostate endocrine physiology.

	Acknowledgments

 
We thank Ms. Amanda Wiseman, Ms. Kathy Winter, and Ms. Marilyn Busher for assistance with the clinical aspects of the study and Auxilium Pharmaceuticals for the gift of 1% Testim gel.

	Footnotes

 
This work was supported by the Department of Veterans Affairs Special Fellowship in Advanced Geriatrics (to S.T.P.), the Endocrine Society Solvay Clinical Research Award (to S.T.P.), the National Institute of Child Health and Human Development through cooperative agreements U54-HD-12629 and U54 HD42454, as part of the specialized Cooperative Centers Program in Reproductive Research and the Cooperative Contraceptive Research Centers Program (to J.K.A., A.M.M., and W.J.B.), and National Institutes of Health Grants CA-97186 and DK65204 (to P.S.N), and DK65083 (to D.W.L.), and Oregon National Primate Research Center Core Grant NIH/RR00163 (to D.L.H).

Disclosure summary: S.T.P., D.W.L., E.A.M., D.L.H., and L.D.T. have nothing to disclose. J.K.A., W.J.B., and A.M.M. have consulted for GlaxoSmithKline. P.S.N. and A.M.M. have consulted for Solvay Pharmaceuticals. J.K.A. has received grant support from GlaxoSmithKline and Schering-Plough. A.M.M. has received grant support from GlaxoSmithKline, Ascend Therapeutics, and Solvay Pharmaceuticals.

First Published Online August 1, 2006

Abbreviations: AR, Androgen receptor; BPH, benign prostatic hypertrophy; CV, coefficient of variation; DHEA, dehydroepiandrosterone; DHEA-S, DHEA sulfate; DHT, dihydrotestosterone; PSA, prostate-specific antigen; T, testosterone.

Received May 5, 2006.

Accepted July 25, 2006.

	References

Top Abstract Introduction Subjects and Methods Results Discussion References

 

1. Thigpen AE, Silver RI, Guileyardo JM, Casey ML, McConnell JD, Russell DW 1993 Tissue distribution and ontogeny of steroid 5 -reductase isozyme expression. J Clin Invest 92:903–910[Medline]
2. Silver RI, Wiley EL, Davis DL, Thigpen AE, Russell DW, McConnell JD 1994 Expression and regulation of steroid 5 -reductase 2 in prostate disease. J Urol 152:433–437[Medline]
3. Bartsch W, Klein H, Schiemann U, Bauer HW, Voigt KD 1990 Enzymes of androgen formation and degradation in the human prostate. Ann NY Acad Sci 595:53–66[Medline]
4. Labrie F, Luu-The V, Labrie C, Simard J 2001 DHEA and its transformation into androgens and estrogens in peripheral target tissues: intracrinology. Front Neuroendocrinol 22:185–212[CrossRef][Medline]
5. Andriole GL, Humphrey P, Ray P, Gleave ME, Trachtenberg J, Thomas LN, Lazier CB, Rittmaster RS 2004 Effect of the dual 5-reductase inhibitor dutasteride on markers of tumor regression in prostate cancer. J Urol 172:915–919[CrossRef][Medline]
6. Clark RV, Hermann DJ, Cunningham GR, Wilson TH, Morrill BB, Hobbs S 2004 Marked suppression of dihydrotestosterone in men with benign prostatic hyperplasia by dutasteride, a dual 5-reductase inhibitor. J Clin Endocrinol Metab 89:2179–2184[Abstract/Free Full Text]
7. Norman RW, Coakes KE, Wright AS, Rittmaster RS 1993 Androgen metabolism in men receiving finasteride before prostatectomy. J Urol 150:1736–1739[Medline]
8. Bartsch W, Krieg M, Becker H, Mohrmann J, Voigt KD 1982 Endogenous androgen levels in epithelium and stroma of human benign prostatic hyperplasia and normal prostate. Acta Endocrinol (Copenh) 100:634–640[Medline]
9. Hammond GL 1978 Endogenous steroid levels in the human prostate from birth to old age: a comparison of normal and diseased tissues. J Endocrinol 78:7–19[Abstract]
10. Amory JK, Chansky HA, Chansky KL, Camuso MR, Hoey CT, Anawalt BD, Matsumoto AM, Bremner WJ 2002 Preoperative supraphysiological testosterone in older men undergoing knee replacement surgery. J Am Geriatr Soc 50:1698–1701[CrossRef][Medline]
11. Karagiannis A, Harsoulis F 2005 Gonadal dysfunction in systemic diseases. Eur J Endocrinol 152:501–513[Abstract/Free Full Text]
12. Forti G, Salerno R, Moneti G, Zoppi S, Fiorelli G, Marinoni T, Natali A, Costantini A, Serio M, Martini L 1989 Three-month treatment with a long-acting gonadotropin-releasing hormone agonist of patients with benign prostatic hyperplasia: effects on tissue androgen concentration, 5 -reductase activity and androgen receptor content. J Clin Endocrinol Metab 68:461–468[Abstract]
13. Mizokami A, Koh E, Fujita H, Maeda Y, Egawa M, Koshida K, Honma S, Keller ET, Namiki M 2004 The adrenal androgen androstenediol is present in prostate cancer tissue after androgen deprivation therapy and activates mutated androgen receptor. Cancer Res 64:765–771[Abstract/Free Full Text]
14. Nishiyama T, Hashimoto Y, Takahashi K 2004 The influence of androgen deprivation therapy on dihydrotestosterone levels in the prostatic tissue of patients with prostate cancer. Clin Cancer Res 10:7121–7126[Abstract/Free Full Text]
15. Mohler JL, Gregory CW, Ford 3rd OH, Kim D, Weaver CM, Petrusz P, Wilson EM, French FS 2004 The androgen axis in recurrent prostate cancer. Clin Cancer Res 10:440–448[Abstract/Free Full Text]
16. Salerno R, Moneti G, Forti G, Magini A, Natali A, Saltutti C, Di Cello V, Costantini A, Serio M 1988 Simultaneous determination of testosterone, dihydrotestosterone and 5 -androstan-3 ,-17 ß-diol by isotopic dilution mass spectrometry in plasma and prostatic tissue of patients affected by benign prostatic hyperplasia. Effects of 3-month treatment with a GnRH analog. J Androl 9:234–240[Abstract/Free Full Text]
17. McConnell JD, Wilson JD, George FW, Geller J, Pappas F, Stoner E 1992 Finasteride, an inhibitor of 5 -reductase, suppresses prostatic dihydrotestosterone in men with benign prostatic hyperplasia. J Clin Endocrinol Metab 74:505–508[Abstract]
18. Herbst KL, Anawalt BD, Amory JK, Bremner WJ 2002 Acyline: the first study in humans of a potent, new gonadotropin-releasing hormone antagonist. J Clin Endocrinol Metab 87:3215–3220[Abstract/Free Full Text]
19. Herbst KL, Coviello AD, Page S, Amory JK, Anawalt BD, Bremner WJ 2004 A single dose of the potent gonadotropin-releasing hormone antagonist acyline suppresses gonadotropins and testosterone for 2 weeks in healthy young men. J Clin Endocrinol Metab 89:5959–5965[Abstract/Free Full Text]
20. Marks LS, Hess DL, Dorey FJ, Luz Macairan M, Cruz Santos PB, Tyler VE 2001 Tissue effects of saw palmetto and finasteride: use of biopsy cores for in situ quantification of prostatic androgens. Urology 57:999–1005[CrossRef][Medline]
21. Resko JA, Ellinwood WE, Pasztor LM, Huhl AE 1980 Sex steroids in the umbilical circulation of fetal rhesus monkeys from the time of gonadal differentiation. J Clin Endocrinol Metab 50:900–905[Abstract]
22. Ruijter E, van de Kaa C, Aalders T, Ruiter D, Miller G, Debruyne F, Schalken J 1998 Heterogeneous expression of E-cadherin and p53 in prostate cancer: clinical implications. BIOMED-II Markers for Prostate Cancer Study Group. Mod Pathol 11:276–281
23. Page ST, Plymate SR, Bremner WJ, Matsumoto AM, Hess DL, Lin DW, Amory JK, Nelson PS, Wu JD 2006 Effect of medical castration on CD4+CD25+ T cells, CD8+T-cell IFN- expression, and NK cells: a physiological role of testosterone and/or its metabolites. Am J Physiol Endocrinol Metab 290:E856—E863
24. Paterson RF, Gleave ME, Jones EC, Zubovits JT, Goldenberg SL, Sullivan LD 1999 Immunohistochemical analysis of radical prostatectomy specimens after 8 months of neoadjuvant hormonal therapy. Mol Urol 3:277–286[Medline]
25. Wolf BB, Green DR 1999 Suicidal tendencies: apoptotic cell death by caspase family proteinases. J Biol Chem 274:20049–20052[Free Full Text]
26. Winter RN, Kramer A, Borkowski A, Kyprianou N 2001 Loss of caspase-1 and caspase-3 protein expression in human prostate cancer. Cancer Res 61:1227–1232[Abstract/Free Full Text]
27. Wolf BB, Schuler M, Echeverri F, Green DR 1999 Caspase-3 is the primary activator of apoptotic DNA fragmentation via DNA fragmentation factor-45/inhibitor of caspase-activated DNase inactivation. J Biol Chem 274:30651–30656[Abstract/Free Full Text]
28. Burnstein KL 2005 Regulation of androgen receptor levels: implications for prostate cancer progression and therapy. J Cell Biochem 95:657–669[CrossRef][Medline]
29. Stanbrough M, Bubley GJ, Ross K, Golub TR, Rubin MA, Penning TM, Febbo PG, Balk SP 2006 Increased expression of genes converting adrenal androgens to testosterone in androgen-independent prostate cancer. Cancer Res 66:2815–2825[Abstract/Free Full Text]
30. Walsh PC, Hutchins GM, Ewing LL 1983 Tissue content of dihydrotestosterone in human prostatic hyperplasis is not supranormal. J Clin Invest 72:1772–1777[Medline]
31. Geller J, Albert J 1987 Effects of castration compared with total androgen blockade on tissue dihydrotestosterone (DHT) concentration in benign prostatic hyperplasia (BPH). Urol Res 15:151–153[Medline]
32. Wilson JD 2001 The role of 5-reduction in steroid hormone physiology. Reprod Fertil Dev 13:673–678[CrossRef][Medline]
33. Geller J, Albert J, Lopez D, Geller S, Niwayama G 1976 Comparison of androgen metabolites in benign prostatic hypertrophy (BPH) and normal prostate. J Clin Endocrinol Metab 43:686–688[Abstract]
34. Krieg M, Nass R, Tunn S 1993 Effect of aging on endogenous level of 5 -dihydrotestosterone, testosterone, estradiol, and estrone in epithelium and stroma of normal and hyperplastic human prostate. J Clin Endocrinol Metab 77:375–381[Abstract]
35. Schanzer W 1996 Metabolism of anabolic androgenic steroids. Clin Chem 42:1001–1020[Abstract/Free Full Text]
36. Roehrborn CG, Boyle P, Nickel JC, Hoefner K, Andriole G 2002 Efficacy and safety of a dual inhibitor of 5--reductase types 1 and 2 (dutasteride) in men with benign prostatic hyperplasia. Urology 60:434–441[CrossRef][Medline]
37. Peters CA, Walsh PC 1987 The effect of nafarelin acetate, a luteinizing-hormone-releasing hormone agonist, on benign prostatic hyperplasia. N Engl J Med 317:599–604[Abstract]
38. Weir EG, Partin AW, Epstein JI 2000 Correlation of serum prostate specific antigen and quantitative immunohistochemistry. J Urol 163:1739–1742[CrossRef][Medline]
39. Bozec A, Ruffion A, Decaussin M, Andre J, Devonec M, Benahmed M, Mauduit C 2005 Activation of caspases-3, -6, and -9 during finasteride treatment of benign prostatic hyperplasia. J Clin Endocrinol Metab 90:17–25[Abstract/Free Full Text]
40. Ohlson N, Wikstrom P, Stattin P, Bergh A 2005 Cell proliferation and apoptosis in prostate tumors and adjacent non-malignant prostate tissue in patients at different time-points after castration treatment. Prostate 62:307–315[CrossRef][Medline]
41. Monti S, Di Silverio F, Iraci R, Martini C, Lanzara S, Falasca P, Poggi M, Stigliano A, Sciarra F, Toscano V 2001 Regional variations of insulin-like growth factor I (IGF-I), IGF-II, and receptor type I in benign prostatic hyperplasia tissue and their correlation with intraprostatic androgens. J Clin Endocrinol Metab 86:1700–1706[Abstract/Free Full Text]

This article has been cited by other articles:

				R. B. Montgomery, E. A. Mostaghel, R. Vessella, D. L. Hess, T. F. Kalhorn, C. S. Higano, L. D. True, and P. S. Nelson Maintenance of Intratumoral Androgens in Metastatic Prostate Cancer: A Mechanism for Castration-Resistant Tumor Growth Cancer Res., June 1, 2008; 68(11): 4447 - 4454. [Abstract] [Full Text] [PDF]

				S. R. Plymate, K. Haugk, I. Coleman, L. Woodke, R. Vessella, P. Nelson, R. B. Montgomery, D. L. Ludwig, and J. D. Wu An Antibody Targeting the Type I Insulin-like Growth Factor Receptor Enhances the Castration-Induced Response in Androgen-Dependent Prostate Cancer Clin. Cancer Res., November 1, 2007; 13(21): 6429 - 6439. [Abstract] [Full Text] [PDF]

				E. B. Askew, R. T. Gampe Jr., T. B. Stanley, J. L. Faggart, and E. M. Wilson Modulation of Androgen Receptor Activation Function 2 by Testosterone and Dihydrotestosterone J. Biol. Chem., August 31, 2007; 282(35): 25801 - 25816. [Abstract] [Full Text] [PDF]

				S. A. Hall, S. T. Page, T. G. Travison, R. B. Montgomery, C. L. Link, and J. B. McKinlay Do Statins Affect Androgen Levels in Men? Results from the Boston Area Community Health Survey Cancer Epidemiol. Biomarkers Prev., August 1, 2007; 16(8): 1587 - 1594. [Abstract] [Full Text] [PDF]

				E. A. Mostaghel, S. T. Page, D. W. Lin, L. Fazli, I. M. Coleman, L. D. True, B. Knudsen, D. L. Hess, C. C. Nelson, A. M. Matsumoto, et al. Intraprostatic Androgens and Androgen-Regulated Gene Expression Persist after Testosterone Suppression: Therapeutic Implications for Castration-Resistant Prostate Cancer Cancer Res., May 15, 2007; 67(10): 5033 - 5041. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) All Versions of this Article: 91/10/3850    most recent Author Manuscript (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Page, S. T. Articles by Bremner, W. J. Search for Related Content PubMed PubMed Citation Articles by Page, S. T. Articles by Bremner, W. J. Related Collections Male Endocrinology