The effect of finasteride in men with benign prostatic hyperplasia. The Finasteride Study Group

BACKGROUND

Benign prostatic hyperplasia is a progressive, androgen-dependent disease resulting in enlargement of the prostate gland and urinary obstruction. Preventing the conversion of testosterone to its tissue-active form, dihydrotestosterone, by inhibiting the enzyme 5 alpha-reductase could decrease the action of androgens in their target tissues; in the prostate the result might be a decrease in prostatic hyperplasia and therefore in symptoms of urinary obstruction.

METHODS

In a double-blind study, we evaluated the effect of two doses of finasteride (1 mg and 5 mg) and placebo, each given once daily for 12 months, in 895 men with prostatic hyperplasia. Urinary symptoms, urinary flow, prostatic volume, and serum concentrations of dihydrotestosterone and prostate-specific antigen were determined periodically during the treatment period.

RESULTS

As compared with the men in the placebo group, the men treated with 5 mg of finasteride per day had a significant decrease in total urinary-symptom scores (P less than 0.001), an increase of 1.6 ml per second (22 percent, P less than 0.001) in the maximal urinary-flow rate, and a 19 percent decrease in prostatic volume (P less than 0.001). The men treated with 1 mg of finasteride per day did not have a significant decrease in total urinary-symptom scores, but had an increase of 1.4 ml per second (23 percent) in the maximal urinary-flow rate, and an 18 percent decrease in prostatic volume. The men given placebo had no changes in total urinary-symptom scores, an increase of 0.2 ml per second (8 percent) in the maximal urinary-flow rate, and a 3 percent decrease in prostatic volume. The frequency of adverse effects in the three groups was similar, except for a higher incidence of decreased libido, impotence, and ejaculatory disorders in the finasteride-treated groups.

CONCLUSIONS

The treatment of benign prostatic hyperplasia with 5 mg of finasteride per day results in a significant decrease in symptoms of obstruction, an increase in urinary flow, and a decrease in prostatic volume, but at a slightly increased risk of sexual dysfunction.

Steroid 5alpha-reductase deficiency in man: an inherited form of male pseudohermaphroditism

In male pseudohermaphrodites born with ambiguity of the external genitalia but with marked virilization at puberty, biochemical evaluation reveals a marked decrease in plasma dihydrotestosterone secondary to a decrease in steroid 5alpha-reductase activity. In utero the decrease in dihydrotestosterone results in incomplete masculinization of the external genitalia. Inheritance is autosomal recessive.

Endogenous Hormones and Prostate Cancer Collaborative Group, Roddam AW, Allen NE, Appleby P, Key TJ. Endogenous sex hormones and prostate cancer: a collaborative analysis of 18 prospective studies

BACKGROUND

Sex hormones in serum have been hypothesized to influence the risk of prostate cancer. We performed a collaborative analysis of the existing worldwide epidemiologic data to examine these associations in a uniform manner and to provide more precise estimates of risks.

METHODS

Data on serum concentrations of sex hormones from 18 prospective studies that included 3886 men with incident prostate cancer and 6438 control subjects were pooled by the Endogenous Hormones and Prostate Cancer Collaborative Group. Relative risks (RRs) of prostate cancer by fifths of serum hormone concentration were estimated by use of conditional logistic regression with stratification by study, age at recruitment, and year of recruitment. All statistical tests were two-sided.

RESULTS

No associations were found between the risk of prostate cancer and serum concentrations of testosterone, calculated free testosterone, dihydrotestosterone, dehydroepiandrosterone sulfate, androstenedione, androstanediol glucuronide, estradiol, or calculated free estradiol. The serum concentration of sex hormone-binding globulin was modestly inversely associated with prostate cancer risk (RR in the highest vs lowest fifth = 0.86, 95% confidence interval = 0.75 to 0.98; P(trend) = .01). There was no statistical evidence of heterogeneity among studies, and adjustment for potential confounders made little difference to the risk estimates.

CONCLUSIONS

In this collaborative analysis of the worldwide data on endogenous hormones and prostate cancer risk, serum concentrations of sex hormones were not associated with the risk of prostate cancer.

Efficacy and safety of a dual inhibitor of 5-alpha-reductase types 1 and 2 (dutasteride) in men with benign prostatic hyperplasia

OBJECTIVES

To study the efficacy and safety of dutasteride, a dual inhibitor of the 5-alpha-reductase isoenzymes types I and II.

METHODS

A total of 4325 men (2951 completed) with clinical benign prostatic hyperplasia, moderate to severe symptoms (American Urological Association-Symptom Index score of 12 points or greater), a peak flow rate of 15 mL/s or less, a prostate volume of 30 cm3 or greater (as measured by transrectal ultrasonography), and a serum prostate-specific antigen level of 1.5 to 10.0 ng/mL (inclusive) were enrolled into three identical clinical trials and randomized to 0.5 mg dutasteride daily or placebo. After a 1-month, single-blind, placebo lead-in, patients were followed up for 24 months in a double-blind trial with multiple interval assessments.

RESULTS

At 24 months, serum dihydrotestosterone was reduced from baseline by a mean of 90.2% (median -93.7%; P <0.001), and the total prostate and transition zone volumes were reduced by a mean of 25.7% and 20.4%, respectively (P <0.001). The symptom score was improved by as early as 3 months, with pooled significance from 6 months onward (P <0.001) and a reduction of 4.5 points (21.4%) at 24 months (P <0.001). The maximal flow rate improved significantly from 1 month (P <0.01), with an increase of 2.2 mL/s reported at 24 months (P <0.001). Hence, the risk reduction of acute urinary retention was 57% and the risk reduction of benign prostatic hyperplasia-related surgical intervention was 48% compared with placebo. The drug was well tolerated.

CONCLUSIONS

Dutasteride is a potent inhibitor of dihydrotestosterone production that is safe and effective in terms of the reduction of prostate volume and symptoms, flow rate improvement, and the reduction of the risk of acute urinary retention and surgery during a 24-month study period.

Prospective study of sex hormone levels and risk of prostate cancer

BACKGROUND

Sex steroids, particularly androgens, have been implicated in the pathogenesis of prostate cancer. Data from previous studies comparing circulating hormone levels in men with and without prostate cancer are difficult to interpret, since the studies were limited in size, hormone levels were analyzed in blood drawn after the diagnosis of cancer, nonrepresentative control subjects were used, and hormone and hormone-binding protein levels were not simultaneously adjusted.

PURPOSE

We conducted a prospective, nested case-control study to investigate whether plasma hormone and sex hormone-binding globulin (SHBG) levels in healthy men were related to the subsequent development of prostate cancer.

METHODS

Among participants in the Physicians' Health Study who provided plasma samples in 1982, we identified 222 men who developed prostate cancer by March 1992. Three hundred ninety control subjects, matched to the case patients on the bases of age, smoking status, and length of follow-up, were also identified. Immunoassays were used to measure the levels of total testosterone, dihydrotestosterone (DHT), 3 alpha-androstanediol glucuronide (AAG), estradiol, SHBG, and prolactin in the stored (at -82 degrees C) plasma samples. Correlations between individual hormone levels and between hormone levels and SHBG in the plasma of control subjects were assessed by use of Spearman correlation coefficients (r). Odds ratios (ORs) and 95% confidence intervals (CIs) specifying the prostate cancer risk associated with quartile levels of individual hormones, before and after adjustment for other hormones and SHBG, were calculated by use of conditional logistic regression modeling. Reported P values are two-sided.

RESULTS

No clear associations were found between the unadjusted levels of individual hormones or SHBG and the risk of prostate cancer. However, a strong correlation was observed between the levels of testosterone and SHBG (r = .55), and weaker correlations were detected between the levels of testosterone and the levels of both estradiol (r = .28) and DHT (r = .32) (all P < .001). When hormone and SHBG levels were adjusted simultaneously, a strong trend of increasing prostate cancer risk was observed with increasing levels of plasma testosterone (ORs by quartile = 1.00, 1.41, 1.98, and 2.60 [95% CI = 1.34-5.02]; P for trend = .004), an inverse trend in risk was seen with increasing levels of SHBG (ORs by quartile = 1.00, 0.93, 0.61, and 0.46 [95% CI = 0.24-0.89]; P for trend = .01), and a non-linear inverse association was found with increasing levels of estradiol (ORs by quartile = 1.00, 0.53, 0.40, and 0.56 [95% CI = 0.32-0.98]; P for trend = .03). No associations were detected between the levels of DHT or prolactin and prostate cancer risk; for AAG, a marker of 5 alpha-reductase activity, only suggestive evidence of a positive association was found. The results were essentially unchanged when case patients diagnosed within 4 years of plasma collection, case patients diagnosed with localized (i.e., nonaggressive) disease, or control subjects with elevated prostate serum antigen levels (> 2.5 ng/mL) were excluded from the analyses.

CONCLUSIONS

High levels of circulating testosterone and low levels of SHBG-both within normal endogenous ranges-are associated with increased risks of prostate cancer. Low levels of circulating estradiol may represent an additional risk factor. Circulating levels of DHT and AAG do not appear to be strongly related to prostate cancer risk.

Activation of programmed cell death in the rat ventral prostate after castration

The rapid involution of the rat ventral prostate after castration is an active process initiated by removal of the inhibitory effects of androgen on prostatic cell death. The present studies demonstrate that after castration-induced androgen deprivation a series of temporally discrete biochemical events are activated which result in the rapid programmed death of the subset of androgen-dependent cells within the rat ventral prostate. These biochemical steps involve 1) rapid loss of nuclear androgen receptor retention; by 12 h after castration, androgen receptors are no longer detectable in ventral prostatic nuclei; 2) an initial fragmentation of nuclear DNA into low mol wt (less than 1000 basepairs) nucleosomal oligomers which lack intranucleosomal break points; and 3) eventual complete digestion of these nucleosomal oligomers into component nucleotides. Additional studies demonstrate that activation of a Ca2+-Mg2+-dependent endonuclease is associated with this DNA fragmentation. By 4 days after castration, maximal DNA fragmentation is obtained, with 15% of the total nuclear DNA extractable as low mol wt fragments. Proteolytic enzymes are apparently not involved initially in this process, suggesting that DNA fragmentation is a discrete event in, rather than a result of, cell death. Flow cytometric analysis of nuclear DNA content demonstrated that each day after castration, a subpopulation of androgen-dependent cells in rat ventral prostate fragmented all of their genomic DNA, as opposed to the whole population of cells fragmenting an increasing portion of their DNA daily.

The determination of five steroids in avian plasma by radioimmunoassay and competitive protein-binding

A method has been developed for the simultaneous determination of testosterone, 5alpha-dihydrotestosterone and corticosterone, or of estrone, estradiol-17beta and corticosterone, after separation on a Celite:propylene glycol:ethylene glycol column (6:1.5:1.5 w/v/v). The lower quarter of the column was packed with a Celite: water mixture (3:1 w/v) as a stationary phase (glycol) 'trap'. This effectively prevented leaching of the glycols into the eluate as the concentration of ethyl acetate in the mobile phase was increased to elute the more polar steroids. In addition, a second system utilizing a Celite: ethylene glycol column (2:1 w/v) for the separation of estrone and estradiol-17beta is described. Testosterone, 5alpha-dihydrotestosterone, estrone and estradiol-17beta were measured by radioimmunoassay and corticosterone by a competitive protein-binding technique. Reliability criteria are presented showing that the assay systems used are accurate and reproducible. Plasma-steroid levels of eight avian species are also presented and compared with those found by other investigators.

Finasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group

BACKGROUND

Androgenetic alopecia (male pattern hair loss) is caused by androgen-dependent miniaturization of scalp hair follicles, with scalp dihydrotestosterone (DHT) implicated as a contributing cause. Finasteride, an inhibitor of type II 5alpha-reductase, decreases serum and scalp DHT by inhibiting conversion of testosterone to DHT.

OBJECTIVE

Our purpose was to determine whether finasteride treatment leads to clinical improvement in men with male pattern hair loss.

METHODS

In two 1-year trials, 1553 men (18 to 41 years of age) with male pattern hair loss received oral finasteride 1 mg/d or placebo, and 1215 men continued in blinded extension studies for a second year. Efficacy was evaluated by scalp hair counts, patient and investigator assessments, and review of photographs by an expert panel.

RESULTS

Finasteride treatment improved scalp hair by all evaluation techniques at 1 and 2 years (P < .001 vs placebo, all comparisons). Clinically significant increases in hair count (baseline = 876 hairs), measured in a 1-inch diameter circular area (5.1 cm2) of balding vertex scalp, were observed with finasteride treatment (107 and 138 hairs vs placebo at 1 and 2 years, respectively; P < .001). Treatment with placebo resulted in progressive hair loss. Patients' self-assessment demonstrated that finasteride treatment slowed hair loss, increased hair growth, and improved appearance of hair. These improvements were corroborated by investigator assessments and assessments of photographs. Adverse effects were minimal.

CONCLUSION

In men with male pattern hair loss, finasteride 1 mg/d slowed the progression of hair loss and increased hair growth in clinical trials over 2 years.

Marked decline in serum concentrations of adrenal C19 sex steroid precursors and conjugated androgen metabolites during aging

The present data show a dramatic decline in the circulating levels of dehydroepiandrosterone (DHEA), DHEA-sulfate (DHEA-S), androst-5-ene-3 beta,17 beta-diol (5-diol), 5-diol-sulfate, 5-diol-fatty acid esters, and androstenedione in both men and women between the ages of 20-80 yr. In the 50- to 60-yr-old group, serum DHEA decreased by 74% and 70% from its peak values in 20- to 30-yr-old men and women, respectively. the serum concentrations of the conjugated metabolites of dihydrotestosterone (DHT), namely androsterone (ADT)-G, androstane-3 alpha,17 beta-diol (3 alpha-diol-G), androstane-3 beta,17 beta-diol (3 beta-diol-G), and ADT-sulfate are the most reliable parameters of the total androgen pool in both men and women, whereas serum testosterone and DHT can be used as markers of testicular secretion in men and interstitial ovarian secretion in women. The serum concentration of these various conjugated androgen metabolites decreased by 40.8% to 72.8% between the 20- to 30-yr-old and 70- to 80-yr-old age groups in men and women, respectively, thus suggesting a parallel decrease in the total androgen pool with age. As estimated by measurement of the circulating levels of these conjugated metabolites of DHT, it is noteworthy that women produce approximately 66% of the total androgens found in men. In women, most of these androgens originate from the transformation of DHEA and DHEA-S into testosterone and DHT in peripheral intracrine tissues, whereas in men the testes and DHEA and DHEA-S provide approximately equal amounts of androgens at the age of 50-60 yr. An additional potentially highly significant observation is that the majority of the marked decline in circulating adrenal C19 steroids and their resulting androgen metabolites takes place between the age groups of 20- to 30-yr olds and 50- to 60-yr-olds, with smaller changes are observed after the age of 60 yr.

Marked suppression of dihydrotestosterone in men with benign prostatic hyperplasia by dutasteride, a dual 5alpha-reductase inhibitor

Dihydrotestosterone (DHT) is the primary metabolite of testosterone in the prostate and skin. Testosterone is converted to DHT by 5alpha-reductase, which exists in two isoenzyme forms (types 1 and 2). DHT is associated with development of benign prostatic hyperplasia (BPH), and reduction in its level with 5alpha-reductase inhibitors improves the symptoms associated with BPH and reduces the risk of acute urinary retention and prostate surgery. A selective inhibitor of the type 2 isoenzyme (finasteride) has been shown to decrease serum DHT by about 70%. We hypothesized that inhibition of both isoenzymes with the dual inhibitor dutasteride would more effectively suppress serum DHT levels than selective inhibition of only the type 2 isoenzyme. A total of 399 patients with BPH were randomized to receive once-daily dosing for 24 wk of dutasteride (0.01, 0.05, 0.5, 2.5, or 5.0 mg), 5 mg finasteride, or placebo. The mean percent decrease in DHT was 98.4 +/- 1.2% with 5.0 mg dutasteride and 94.7 +/- 3.3% with 0.5 mg dutasteride, significantly lower (P < 0.001) and with less variability than the 70.8 +/- 18.3% suppression observed with 5 mg finasteride. Mean testosterone levels increased but remained in the normal range for all treatment groups. Dutasteride appeared to be well tolerated with an adverse event profile similar to placebo.

AA2500 testosterone gel normalizes androgen levels in aging males with improvements in body composition and sexual function

Testosterone replacement in hypogonadal men improves body composition, mood, and sexual functioning. In this 90-d study, we compared the pharmacokinetics and treatment effectiveness of a topical testosterone gel (AA2500) at two concentrations, 50 mg/d and 100 mg/d, to a testosterone patch and placebo gel in 406 hypogonadal men. Pharmacokinetic profiles were obtained, body composition was measured, and mood and sexual function were monitored. AA2500 treatments resulted in dose-dependent improvements in all pharmacokinetic parameters, compared with testosterone patch and placebo. Mean average concentrations at d 90 T were 13.8, 17.1, 11.9, and 7.3 nmol/liter for 50 mg/d AA2500, 100 mg/d AA2500, testosterone patch, and placebo, respectively. At d 90, the 100 mg/d AA2500 treatment improved lean body mass by 1.7 kg and percentage of body fat by 1.2% to a significantly greater degree than either control treatment. Significant improvements in spontaneous erections, sexual desire, and sexual motivation were also evidenced with the 100 mg/d AA2500 dose in comparison with placebo. Testosterone gel was well tolerated; however, the testosterone patch resulted in a high rate of application site reactions. Overall, AA2500 is an effective, well tolerated treatment for hypogonadism.

Male pseudohermaphroditism due to steroid 5-alpha-reductase deficiency

A new inherited form of male pseudohermaphroditism has been investigated in a pedigree of 24 families with 38 affected males. At birth, the affected males (46 XY) have a clitoral-like phallus, bifid scrotum and urogenital sinus. The testes are in the inguinal canals or labial-scrotal folds. The Wolffian structures are normally differentiated; there are no Mullerian structures. At puberty a muscular male habitus develops with growth of the phallus and scrotum, voice change and no gynecomastia. The subjects have erections, ejaculations and a libido directed towards females. They have decreased body hair, a scant to absent beard, no temporal hair line recession and a small prostate. Testicular biopsy reveals a normal testis. The mean plasma T levels in affected adults are significantly higher, and the mean plasma DHT levels are significantly lower when compared to those in normal subjects. The plasma T:DHT ratios range from 35 to 84 compared to 8 to 16 in normal subjects. After the administration of hCG, the T:DHT ratios in affected male children range from 74 to 162 compared to 3 to 26 in the control subjects. In affected adults, mean plasma LH and FSH levels are significantly higher than in normal subjects. In the affected subjects, the metabolic clearance rates of T and DHT are normal, but the conversion ratio of T to DHT is less than 1 per cent. The endogenous mean urinary E:A and E-OH:A-OH ratios, and the urinary E:A and E-OH:A-OH ratios after the infusion of radioactive T are significantly higher than in normal males. Inheritance is autosomal recessive with some sibling sisters showing the same biochemical defect, and obligate carrier parents showing an intermediate defect. These data support our thesis that the defect in these male pseudohermaphrodites is secondary to decreased steroid delta 4-5 alpha-reductase activity. The affected subjects provide a clinical model for delineating the roles of T and DHT in sexual differentiation and development. This entity also demonstrates an inherited disorder of steroid metabolism in which the basic enzyme deficiency resides in the target tissues.

The effect of diurnal variation on clinical measurement of serum testosterone and other sex hormone levels in men

CONTEXT

Although diurnal variation of testosterone and other hormones in men has been well documented, the effect of this variation on sampling during typical clinic hours has not been examined.

OBJECTIVE

Our objective was to examine temporal variation in serum testosterone and five other hormones in men over normal clinic hours.

DESIGN

Blood samples were collected at six separate visits, three morning visits 1-3 d apart and three afternoon visits 1-3 d apart.

SETTING AND PARTICIPANTS

In Boston, MA, 66 men participated, 30-80 yr of age, randomly selected from the Boston Area Community Health Survey who completed at least five visits.

MAIN OUTCOME MEASURES

The age-specific ratio of hormone level at times ranging from 0801-1600 h to hormone level at 0800 h was calculated. Ratios were calculated from parameter estimates obtained from cosinor models.

RESULTS

In men 30-40 yr old, testosterone levels were 20-25% lower at 1600 h than at 0800 h. The difference declined with age, with a 10% difference at 70 yr. 17 men with at least one of three measurements less than 300 ng/dl (10.4 nmol/liter) after 1200 h had normal testosterone levels at all three visits before 1200 h (five of eight men 30-47 yr old, four of nine men 66-80 yr old). Much lower levels of diurnal variation were found for dihydrotestosterone, SHBG, LH, FSH, and estradiol at all ages.

CONCLUSIONS

Our results support the recommendation of restricting testosterone measurements to morning hours in both young and older men. Limited diurnal variation in other hormones indicates that sampling through the day is appropriate.

Measurement of a Comprehensive Sex Steroid Profile in Rodent Serum by High-Sensitive Gas Chromatography-Tandem Mass Spectrometry

Accurate measurement of sex steroid concentrations in rodent serum is essential to evaluate mouse and rat models for sex steroid-related disorders. The aim of the present study was to develop a sensitive and specific gas chromatography-tandem mass spectrometry (GC-MS/MS) method to assess a comprehensive sex steroid profile in rodent serum. A major effort was invested in reaching an exceptionally high sensitivity for measuring serum estradiol concentrations. We established a GC-MS/MS assay with a lower limit of detection for estradiol, estrone, T, DHT, progesterone, androstenedione, and dehydroepiandrosterone of 0.3, 0.5, 4.0, 1.6, 8, 4.0, and 50 pg/mL, respectively, whereas the corresponding values for the lower limit of quantification were 0.5, 0.5, 8, 2.5, 74, 12, and 400 pg/mL, respectively. Calibration curves were linear, intra- and interassay coefficients of variation were low, and accuracy was excellent for all analytes. The established assay was used to accurately measure a comprehensive sex steroid profile in female rats and mice according to estrous cycle phase. In addition, we characterized the impact of age, sex, gonadectomy, and estradiol treatment on serum concentrations of these sex hormones in mice. In conclusion, we have established a highly sensitive and specific GC-MS/MS method to assess a comprehensive sex steroid profile in rodent serum in a single run. This GC-MS/MS assay has, to the best of our knowledge, the best detectability reported for estradiol. Our method therefore represents an ideal tool to characterize sex steroid metabolism in a variety of sex steroid-related rodent models and in human samples with low estradiol levels.

The effect of six months treatment with a 100 mg daily dose of dehydroepiandrosterone (DHEA) on circulating sex steroids, body composition and muscle strength in age-advanced men and women

OBJECTIVE

The biological role of the adrenal sex steroid precursors--DHEA and DHEA sulphate (DS) and their decline with ageing remains undefined. We observed previously that administration of a 50 daily dose of DHEA for 3 months to age-advanced men and women resulted in an elevation (10%) of serum levels of insulin-like growth factor-I (IGF-I) accompanied by improvement of self-reported physical and psychological well-being. These findings led us to assess the effect of a larger dose (100 mg) of DHEA for a longer duration (6 months) on circulating sex steroids, body composition (DEXA) and muscle strength (MedX).

SUBJECTS AND DESIGN

Healthy non-obese age-advanced (50-65 yrs of age) men (n = 9) and women (n = 10) were randomized into a double-blind placebo-controlled cross-over trial. Sixteen subjects completed the one-year study of six months of placebo and six months of 100 mg oral DHEA daily.

MEASUREMENTS

Fasting early morning blood samples were obtained. Serum DHEA, DS, sex steroids, IGF-I, IGFBP-1, IGFBP-3, growth hormone binding protein (GHBP) levels and lipid profiles as well as body composition (by DEXA) and muscle strength (by MedX testing) were measured at baseline and after each treatment.

RESULTS

Basal serum levels of DHEA, DS, androsternedione (A), testosterone (T) and dihydrotestosterone (DHT) were at or below the lower range of young adult levels. In both sexes, a 100 mg daily dose of DHEA restored serum DHEA levels to those of young adults and serum DS to levels at or slightly above the young adult range. Serum cortisol levels were unaltered, consequently the DS/cortisol ratio was increased to pubertal (10:1) levels. In women, but not in men, serum A, T and DHT were increased to levels above gender-specific young adult ranges. Basal SHBG levels were in the normal range for men and elevated in women, of whom 7 of 8 were on oestrogen replacement therapy. While on DHEA, serum SHBG levels declined with a greater (P < 0.02) response in women (-40 +/- 8%; P = 0.002) than in men (-5 +/- 4%; P = 0.02). Relative to baseline, DHEA administration resulted in an elevation of serum IGF-I levels in men (16 +/- 6%, P = 0.04) and in women (31 +/- 12%, P = 0.02). Serum levels of IGFBP-1 and IGFBP-3 were unaltered but GHBP levels declined in women (28 +/- 6%; P = 0.02) not in men. In men, but not in women, fat body mass decreased 1.0 +/- 0.4 kg (6.1 +/- 2.6%, P = 0.02) and knee muscle strength 15.0 +/- 3.3% (P = 0.02) as well as lumbar back strength 13.9 +/- 5.4% (P = 0.01) increased. In women, but not in men, an increase in total body mass of 1.4 +/- 0.4 kg (2.1 +/- 0.7%; P = 0.02) was noted. Neither gender had changes in basal metabolic rate, bone mineral density, urinary pyridinoline cross-links, fasting insulin, glucose, cortisol levels or lipid profiles. No significant adverse effects were observed.

CONCLUSIONS

A daily oral 100 mg dose of DHEA for 6 months resulted in elevation of circulating DHEA and DS concentrations and the DS/cortisol ratio. Biotransformation to potent androgens near and slightly above the range of their younger counterparts occurred in women with no detectable change in men. Given this hormonal milieu, an increase in serum IGF-I levels was observed in both genders but dimorphic responses were evident in fat body mass and muscle strength in favour of men. These differences in response to DHEA administration may reflect a gender specific response to DHEA and/or the presence of confounding factor(s) in women such as oestrogen replacement therapy.

Androgens and diabetes in men: results from the Third National Health and Nutrition Examination Survey (NHANES III)

OBJECTIVE

Low levels of androgens in men may play a role in the development of diabetes; however, few studies have examined the association between androgen concentration and diabetes in men in the general population. The objective of this study is to test the hypothesis that low normal levels of total, free, and bioavailable testosterone are associated with prevalent diabetes in men.

RESEARCH DESIGN AND METHODS

The study sample included 1,413 adult men aged > or =20 years who participated in the morning session of the first phase of the Third National Health and Nutrition Examination Survey, a cross-sectional survey of the civilian, noninstitutionalized population of the U.S. Bioavailable and free testosterone levels were calculated from serum total testosterone, sex hormone-binding globulin, and albumin concentrations.

RESULTS

In multivariable models adjusted for age, race/ethnicity, and adiposity, men in the first tertile (lowest) of free testosterone level were four times more likely to have prevalent diabetes compared with men in the third tertile (odds ratio 4.12 [95% CI 1.25-13.55]). Similarly, men in the first tertile of bioavailable testosterone also were approximately four times as likely to have prevalent diabetes compared with men in the third tertile (3.93 [1.39-11.13]). These associations persisted even after excluding men with clinically abnormal testosterone concentrations defined as total testosterone <3.25 ng/ml or free testosterone <0.07 ng/ml. No clear association was observed for total testosterone after multivariable adjustment (P for trend across tertiles = 0.27).

CONCLUSIONS

Low free and bioavailable testosterone concentrations in the normal range were associated with diabetes, independent of adiposity. These data suggest that low androgen levels may be a risk factor for diabetes in men.

Sex hormones prolong the QT interval and downregulate potassium channel expression in the rabbit heart

BACKGROUND

Sex hormones are known to exert direct and indirect effects on cardiovascular function, but their effects on cardiac repolarization have not been elucidated. The repolarization phase of the cardiac action potential or QT interval of the ECG is regulated largely by potassium channels such as the delayed rectifier currents HK2 and IsK.

METHODS AND RESULTS

The effects of ovariectomy (OVX) and estradiol (E2) or dihydrotestosterone (DHT) treatment were evaluated on HK2, HERG, and IsK mRNA levels, QT duration, and quinidine-induced changes in QT interval in isolated rabbit hearts. HK2 and 0.7-kilobase IsK mRNA were downregulated in cardiac ventricular tissue from OVX rabbits treated with either E2 or DHT. The QT interval was prolonged in E2- and DHT-treated animals (OVX + vehicle, 223 +/- 6 ms; OVX + DHT, 236 +/- 10 ms; and OVX + DHT, 245 +/- 6 ms; P < .05).

CONCLUSIONS

The association between hormone-induced changes in baseline QT interval and the mRNA level for these channels suggests that sex hormones may play a critical role in regulating cardiac repolarization. However, the changes in baseline QT and potassium channel mRNA after hormone treatment were not concordant with the changes in QT interval after the infusion of quinidine, after which E2-treated animals responded similarly to controls (18.4 +/- 4.6% and 19.3 +/- 4.6% increase in QT interval, respectively) and DHT-treated animals exhibited less QT prolongation (11.4 +/- 3.8% increase; P < .03).

The hormonal activity of the postmenopausal ovary

The origin of plasma sex hormones in postmenopausal women was studied by determining plasma levels under basal conditions, after ACTH stimulation, and after dexamethasone suppression, as well as after hCG stimulation. Values obtained in postmenopausal women were compared with values observed during the follicular phase of the cycle in young women on the one hand, and with values in ovariectomized women of postmenopausal age on the other hand. All sex steroid levels studied with the exception of estrone, were significantly lower in postmenopausal women than in young women during the early follicular phase of the cycle. In ovariectomized women only androgen levels (testosterone, androstenedione, dihydrotestosterone, and to a lesser extent dehydroepiandrosterone,) were lower than in normal postmenopausal women, estrogen, 17 hydroxyprogesterone, and progesterone levels being similar. ACTH increased all plasma steroid levels except estradiol, whereas after dexamethasone, all sex hormone levels were significantly decreased. hCG stimulation finally caused an increase of borderline statistical significance in testosterone, dehydroepiandrosterone, and 17-hydroxyprogesterone levels. We have concluded from this study that the adrenal cortex is almost the exclusive source of plasma estradiol, estrone, progesterone, and 17OH progesterone and the most important source of plasma dehydroepiandrosterone; that the postmenopausal ovary appears to be responsible for about 50% of plasma testosterone and 30% of androstenedione levels; and that hCG stimulation with 5000 IU daily for 3 days, hardly influences steroid secretion by postmenopausal ovaries.

Insulin-like growth factor 1 in relation to prostate cancer and benign prostatic hyperplasia

Blood samples were collected from 52 incident cases of histologically confirmed prostate cancer, an equal number of cases of benign prostatic hyperplasia (BPH) and an equal number of apparently healthy control subjects. The three groups were matched for age and town of residence in the greater Athens area. Steroid hormones, sex hormone-binding globulin, and insulin-like growth factor 1 (IGF-1) were measured in duplicate by radioimmunoassay in a specialized US centre. Statistical analyses were performed using multiple logistical regression. The results for IGF-1 in relation to prostate cancer and BPH were adjusted for demographic and anthropometric factors, as well as for the other measured hormones. There was no relation between IGF-1 and BPH, but increased values of this hormone were associated with increased risk of prostate cancer; an increment of 60 ng ml(-1) corresponded to an odds ratio of 1.91 with a 95% confidence interval of 1.00-3.73. There was also some evidence for an interaction between high levels of testosterone and IGF-1 in relation to prostate cancer. This finding suggests that, in addition to testosterone, IGF-1 may increase the risk of prostate cancer in humans.

Bioavailable testosterone and depressed mood in older men: the Rancho Bernardo Study

A cross-sectional population-based study examined the association between endogenous sex hormones and depressed mood in community-dwelling older men. Participants included 856 men, ages 50-89 yr, who attended a clinic visit between 1984-87. Total and bioavailable testosterone, total and bioavailable estradiol, and dihydrotestosterone levels were measured by radioimmunoassay in an endocrinology research laboratory. Depressed mood was assessed with the Beck Depression Inventory (BDI). Levels of bioavailable testosterone and bioavailable estradiol decreased with age, but total testosterone, dihydrotestosterone, and total estradiol did not. BDI scores increased with age. Low bioavailable testosterone levels and high BDI scores were associated with weight loss and lack of physical activity, but not with cigarette smoking or alcohol intake. By linear regression or quartile analysis the BDI score was significantly and inversely associated with bioavailable testosterone (both Ps = 0.007), independent of age, weight change, and physical activity; similar associations were seen for dihydrotestosterone (P = 0.048 and P = 0.09, respectively). Bioavailable testosterone levels were 17% lower for the 25 men with categorically defined depression than levels observed in all other men (P = 0.01). Neither total nor bioavailable estradiol was associated with depressed mood. These results suggest that testosterone treatment might improve depressed mood in older men who have low levels of bioavailable testosterone. A clinical trial is necessary to test this hypothesis.

Hormonal predictors of prostate cancer: a meta-analysis

PURPOSE

Although there is strong circumstantial evidence that androgens are implicated in the etiology of prostate cancer, epidemiologic investigations have failed to demonstrate consistently that one or more steroid hormones are implicated. In contrast, recent epidemiologic studies unequivocally link serum insulin-like growth factor 1 (IGF-1) levels with risk for prostate cancer.

METHODS

We have performed the first meta-analysis of all previously published studies on hormonal predictors of risk for prostate cancer.

RESULTS

A meta-analysis restricted to studies that performed mutual adjustment for all measured serum hormones, age, and body mass index indicated that men whose total testosterone is in the highest quartile are 2.34 times more likely to develop prostate cancer (95% confidence interval, 1.30 to 4.20). In contrast, levels of dihydrotestosterone and estradiol do not seem to play a role of equal importance. The only study that provides multivariably adjusted sex hormone-binding globulin data indicates that this binding protein is inversely related to prostate cancer risk (odds ratio, 0.46; 95% confidence interval, 0.24 to 0.89). Finally, all three studies that examined the role of serum IGF-1 have consistently demonstrated a positive and significant association with prostate cancer risk that is similar in magnitude to that of testosterone.

CONCLUSION

Men with either serum testosterone or IGF-1 levels in upper quartile of the population distribution have an approximately two-fold higher risk for developing prostate cancer.

Changes in glucose tolerance over time in women with polycystic ovary syndrome: a controlled study

We performed this study to access the changes in glucose tolerance over time in a group of women with polycystic ovary syndrome (PCOS) (n = 71) and control women (n = 23) with regular menstrual cycles and baseline normal glucose tolerance. Mean follow-up was between 2 and 3 yr for both groups (PCOS 2.5 +/- 1.7 yr; controls 2.9 +/- 2.1 yr). Based on World Health Organization glucose tolerance categories, there was no significant difference in the prevalence of glucose intolerance at follow-up in the PCOS group. In the PCOS group, 25 (37%) had impaired glucose tolerance (IGT) and seven (10%) had type 2 diabetes mellitus at baseline, compared with 30 (45%) and 10 (15%), respectively, at follow-up. There were also no differences within groups (PCOS or control) or between groups (PCOS vs. control) in the oral glucose tolerance test-derived measure of insulin sensitivity, but in the women with PCOS who converted to either IGT or type 2 diabetes mellitus, there was a significant decrease (P < 0.0001). At the follow-up visit, the mean glycohemoglobin level was 6.1 +/- 0.9% in women with PCOS vs. 5.3 +/- 0.7% in the control women (P < 0.001). Women with PCOS and baseline IGT had a low conversion risk of 6% to type 2 diabetes over approximately 3 yr, or 2% per year. The effect of PCOS, given normal glucose tolerance (NGT) at baseline, is more pronounced with 16% conversion to IGT per year. Our study supports that women with PCOS (especially with NGT) should be periodically rescreened for diabetes due to worsening glucose intolerance over time, but this interval may be over several years and not annually.