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PubMed1996

Relative potency of testosterone and dihydrotestosterone in preventing atrophy and apoptosis in the prostate of the castrated rat.

Although dihydrotestosterone (DHT) is the principal androgen in the prostate, testosterone can also act as an androgen in this tissue. To determine the relative potencies of testosterone and DHT in preventing prostate regression, castrated rats were implanted for 4 d with varying doses of testosterone in the presence or absence of the 5alpha-reductase inhibitor finasteride. In the absence of finasteride, testosterone in the prostate is converted to DHT, creating an intraprostatic DHT dose response. In the presence of finasteride, this conversion is blocked, and an intraprostatic testosterone dose response is achieved. DHT was 2.4 times more potent than testosterone at maintaining normal prostate weight and duct lumen mass, a measure of epithelial cell function. The two androgens were equipotent at preventing DNA fragementation and expression of testosterone-repressed prostate message, two measures of apoptosis (cell death). The intraprostatic testosterone concentration that results from finasteride treatment in rats is sufficient to inhibit apoptosis but will not maintain normal epithelial cell activity. In conclusion, whereas DHT is more potent than testosterone at stimulating prostate epithelial cell function as measured by ductal mass, the two androgens are equipotent at preventing prostate cell death after castration. These results explain why finasteride causes prostate involution in the rat with minimal evidence of prostate cell death.

Animals↗
PubMed1996

[Assessment of the effect of a 5-alpha-reductase inhibitor on cultured explants of human prostate].

For the present work, cultures of hyperplastic human prostate explants were performed to evaluate the "in vitro" response of a 5-alpha reductase inhibitor-finasteride. Explants were cultured over a nine-week period in RPMI-1640 media supplemented with Penicillin-Streptomycin 4% and Fetal Bovine Serum 10%. Cultures were divided into one control group, one with testosterone added (1.25 x 10(4) micrograms/ml) and one which received testosterone (1.25 x 10(-4) micrograms/ml) plus finasteride (0,0038 mg/ml). Control explants showed involutive changes throughout the experience, which occurred later in those treated with testosterone and earlier and more marked in the case of finasteride. The testosterone-treated group showed intense positivity for PSA, a marker which reveals specific tissular functions, which remained uniformed in the control group through the entire experiment, and decreased gradually in the finasteride group. In summary, according to our work, culture of organs would be a useful tool for an in vitro evaluation of the hyperplastic human prostate response to the action of the 5-alpha reductase inhibitor, finasteride.

Culture Techniques↗
PubMed1997

Unique preclinical characteristics of GG745, a potent dual inhibitor of 5AR.

Selective inhibition of type 2 5alpha-reductase has been shown to be efficacious in the treatment of benign prostatic hyperplasia. Pharmacokinetic and pharmacodynamic results are reported of treatment with a potent inhibitor of both 5alpha-reductase isozymes, GG745, in rats, dogs and men. In the rat, GG745 has a similar effect on DHT-driven prostatic growth as finasteride, another dual 5alpha-reductase inhibitor in this species. However, GG745 appears to be more potent in the rat, a result that likely reflects the greater inherent potency and terminal half-life of GG745 (14 hr) compared with that of finasteride (1 hr). These pharmacokinetic differences are also maintained in the dog (65 and 4 hr for GG745 and finasteride, respectively). From these results, the literature, and in vitro studies, we estimated doses of GG745 likely to prove efficacious in reducing DHT levels in man. These estimated values were predictive of single-dose effects of GG745 in man. Results from single-dose evaluations in man indicate that GG745 has a terminal half-life of approximately 240 hr, and single doses of >10 mg decreased DHT levels significantly more than did single 5-mg doses of finasteride. These data support the hypothesis that a molecule (GG745) that effectively inhibits both 5alpha-reductases will lower serum DHT levels significantly more than a molecule that inhibits only a single 5alpha-reductase isozyme (e.g., finasteride, a selective inhibitor of the type 2 enzyme in man).

Animals↗
PubMed1998

Haematuria associated with BPH-Natural history and a new treatment option.

Bleeding of prostatic origin is usually caused by the friable hypervascularity of the prostate, the vessels of which are easily disrupted by physical activity. The condition is often ignored after the patient has been fully investigated and more serious causes for bleeding excluded and treatment is often withheld unless the bleeding becomes excessive. We analysed the clinical effect of finasteride in the treatment of this condition. We retrospectively reviewed 42 patients diagnosed as having haematuria secondary to bleeding from a benign prostate. Eighteen patients were simply reassured and given no treatment. Twenty-four patients with prostatic bleeding were treated using finasteride. All case notes were reviewed and the patients were contacted by telephone. Of 18 patients who had prostatic bleeding but did not receive treatment the mean age was 70 y and the mean follow-up was 10 months; two had died, nine had no further bleeding, two had a single episode of bleeding requiring no treatment, six had several bleeding episodes of whom one started finasteride, one refused treatment, and three required TURP. In the group treated with finasteride the mean follow up was 9 months, the mean age of the patients was 75 y. Twenty patients had no further bleeding, one patient experienced minor intermittent bleed and required no further treatment. Two patients died of non-urological causes, one patient stopped the treatment because of impotence and one patient had mild gynecomastia. Haematuria secondary to prostatic bleeding can be significant if not treated. Finasteride appears to be effective in suppressing haematuria caused by benign prostatic hyperplasia and should be considered in treating this problem.

Journal Article↗
PubMed1999

Management of symptomatic BPH in the US: who is treated and how?

OBJECTIVE: To review the contemporary management of symptomatic benign prostatic hyperplasia (BPH) in North America. METHODS: Information was obtained from published scientific articles, lay press articles, Medicare outcomes data, IMS market analysis data and surveys among primary care practitioners and urologists. RESULTS: A survey in Olmsted County in the US identified the number of men with an I-PSS score >7 and maximum urinary flow rate <15 ml/s. This survey found that 17% of men in the 50-59 year old age bracket, 27% of men in the 60-69 bracket and 37% of men in the 70-79 bracket meet this minimum criterion for discussions about treatment. Currently in the US, there are approximately 5.6 million men that fall in this category, and the number is expected to double by the year 2025. Primary care physicians in 25% of cases and internal medicine in 24% of cases provide initial management of BPH. Urologists provide initial management in 37% of cases. Improvement in urinary symptoms and quality of life is the most important health outcome in the management of symptomatic BPH in the US, particularly because serious complications from BPH are distinctly uncommon. A survey among urologists determined that for men with mild symptoms, watchful waiting was employed 77% of the time, alpha(1)-adrenoceptor antagonists 21% and finasteride 1%. For those with moderate symptoms and prostate volume </=40 ml, alpha(1)-adrenoceptor antagonists are employed 88% of the time, finasteride 1% and TURP 1%. When the prostate is in excess of 40 ml, alpha(1)-adrenoceptor antagonists are used 69% of the time, finasteride 10% and TURP 9%. alpha(1)-Adrenoceptor antagonists are also employed most of the time for patients with severe symptoms: 58% of the time for small and 45% of the time for large prostates. The respective data for TURP are 31% and 38%. Primary care physicians utilize predominantly watchful waiting and long-acting alpha(1)-adrenoceptor antagonists. Laser use in the management of BPH has fallen from 40% of urologists in 1994 to 26% in 1997. TUMT and TUNA are each employed by 3% of urologists. The use of transurethral vaporisation of the prostate has increased to 62% of urologists. For those patients being treated with medication, 36% are treated with terazosin, 31% with doxazosin, 15% with finasteride and 18% with tamsulosin, which was introduced only recently and is growing. CONCLUSIONS: In the future, the number of older men in the US will increase dramatically. Likely the percentage of patients undergoing surgical treatment such as TURP will decrease but the absolute number having surgery will increase. It is also likely that alpha(1)-adrenoceptor antagonists will be used with greater frequency in the future and finasteride will be used less frequently. Copyrightz1999S.KargerAG,Basel

Humans↗
PubMed1997

Benign prostatic hyperplasia: diagnosis and treatment guideline.

OBJECTIVE: To critique the US Department of Health and Human Services Public Health Service, Agency for Health Care Policy and Research, Clinical Practice Guideline on Benign Prostatic Hyperplasia: Diagnosis and Treatment; and to provide an update on management and treatment of benign prostatic hyperplasia (BPH) since the Guideline was published. DATA SOURCES: A review of the published medical literature in MEDLINE from 1994 to April 1996, limited in focus to drug treatment of BPH, English language, and human subjects, was performed. STUDY SELECTION: Controlled clinical studies of drug treatment for symptomatic BPH that used objective parameters (e.g., urinary flow rate, prostatic volume, voiding symptom scores) were evaluated. A single reviewer assessed each study. DATA EXTRACTION: Study methods, inclusion and exclusion criteria, and treatment outcomes were assessed for all studies. Independent extraction was performed by a single observer. DATA SYNTHESIS: Management of BPH is directed at ameliorating voiding symptoms. For moderate or severe BPH, medical or surgical therapy should be offered to the majority of patients. Medical therapy options include alpha-adrenergic antagonists and finasteride. The former offer the advantage of a more prompt onset of action (within weeks) when compared with finasteride. Finasteride produces a lower response rate and smaller improvement in voiding symptoms. Combination therapy of terazosin and finasteride has not been proven to be more effective than terazosin monotherapy. CONCLUSIONS: When medical therapy is indicated for moderate or severe BPH, alpha-adrenergic antagonists exhibit a faster onset of action and produce greater improvement of voiding symptoms than does finasteride.

Humans↗
PubMed2000

Antiandrogenic effect of 16-substituted, non-substituted and D-homopregnane derivatives.

The pharmacological activities of 12 pregnane derivatives (4-15) were determined on gonadectomized male hamster flank organs and seminal vesicles as antiandrogens and as 5alpha-reductase inhibitors. The results from this study indicate that subcutaneous injection of testosterone for 3 d increased the diameter of the pigmented spot in the flank organs, whereas finasteride when injected with testosterone decreased the size of the spot significantly when steroids 4-15 were injected together with testosterone, the diameter of the flank organs of gonadectomized male hamsters, decreased significantly (p<0.005) compared to testosterone. Compound 11 was the most active steroid and reduced the diameter of the pigmented spot more than the other synthesized steroids or finasteride. Subcutaneous injections of testosterone to gonadectomized animals restore the seminal vesicle size lost upon castration. Injection of testosterone plus finasteride decreased significantly the weight of these glands (p<0.005). Steroids 5-15 when injected with testosterone decreased the weight of the seminal vesicles compared to testosterone. Finasteride is a good inhibitor of the conversion of testosterone to dihydrotestosterone (DHT) (low formation of DHT) measured as pmole of DHT/g of protein/h. Steroids 6-15 inhibited the conversion of testosterone to DHT as compared to testosterone however finasteride and 10 appeared to be the most effective compounds. Castration increases the protein content of the seminal vesicles (control) expressed as microg/mg of tissues. Testosterone tends to decrease it significantly, as did compounds 4, 5, 7, 9, and 15. We demonstrated that DHT as well as cyproterone acetate and steroids 5, 6, 8, 9, 11, and 14 at increasing non radioactive steroid concentration, inhibited the binding of [3H]DHT to cytosolic androgen receptor (AR), as indicated by its Ki values. However, 4, 7, 10, 12, and 13 did not have any inhibitory effect.

Androgen Antagonists↗
PubMed1997

Terazosin. A pharmacoeconomic evaluation of its use in benign prostatic hyperplasia.

Benign prostatic hyperplasia (BPH) is a common disorder in elderly men which carries a substantial economic burden. Urinary symptoms associated with moderate to severe disease can significantly interfere with daily activities and reduce quality of life. Obstruction of urine flow in men with BPH can result from nonmalignant enlargement of the prostate gland (static component of BPH) and from alpha 1 receptor-mediated increased smooth muscle tone of the bladder neck and prostate (dynamic component of BPH). Transurethral resection of the prostate (TURP) is generally very effective and has traditionally been the standard treatment for men with moderate to severe BPH. However, response to therapy with TURP is not universal and the procedure is associated with a number of potential complications. Moreover, many men prefer to avoid or are not suitable candidates for this invasive procedure. Thus, there is an increasing role for less invasive treatment, including drug therapy, in men with moderate to severe BPH. Terazosin is an alpha 1 receptor antagonist which has been shown in placebo-controlled trials to significantly improve American Urology Association (AUA) symptom and quality-of-life scores and symptom problem index ('bother' score), as well as increase peak urinary flow rate, in men with BPH. In a recent large randomised US trial, treatment for 1 year with terazosin titrated to 10 mg/day improved mean AUA symptom score and peak urinary flow rate to a significantly greater extent than finasteride 5 mg/day in men with moderate to severe BPH. The most frequently reported adverse events associated with terazosin include dizziness, asthenia, postural hypotension, somnolence, headache, peripheral oedema, nasal congestion/rhinitis and syncope. Approximately 5% of men with BPH discontinue terazosin because of adverse events. Results of an economic evaluation of terazosin, in which both clinical and economic data were collected prospectively in a randomised placebo-controlled study design, showed similar total direct treatment costs per 1000 patients associated with 1 year of therapy with terazosin ($US3.57 million) and placebo ($US3.78 million) in men with moderate to severe BPH (1992 dollars). The analysis, which was conducted from the perspective of a managed care organisation in the US, demonstrated that the lower medication costs in the placebo group relative to the terazosin group were offset by increased inpatient care costs. Thus, terazosin (titrated to response up to a maximum of 10 mg/day) was significantly more effective than placebo in improving disease-specific symptoms and quality of life, but at a similar overall cost to placebo. Another economic analysis, also conducted from a third-party payer perspective in the US, modelled direct treatment costs associated with terazosin, finasteride and TURP during the first 2 years after initiating therapy in men with moderate to severe BPH. Results of the study favoured terazosin; the private insurance cost per patient undergoing primary treatment with TURP was $US6411, compared with $US2860 with finasteride (45% of the cost of TURP) and $US2422 with terazosin (38% of the cost of TURP). Medicare costs were lower for all 3 treatment groups but the relative comparisons were similar; corresponding costs per patient were $US3874, $US2161 and $US1820 (1992 dollars). A companion break-even cost analysis used a hypothetical cohort of men with BPH starting treatment at age 67 years. Private insurance costs associated with terazosin remained lower then those associated with TURP for approximately 15 years (the corresponding break-even point was 10 years for finasteride vs TRUP). Medicare costs associated with terazosin would not exceed those of TURP for approximately 7 years (5.5 years for finasteride vs TURP). In conclusion, a limited number of detailed pharmacoeconomic analysis of terazosin have been conducted to date, although it has not been compared with other a1 receptor antagonists.

Adrenergic alpha-Antagonists↗
PubMed1998

Saw palmetto extracts for treatment of benign prostatic hyperplasia: a systematic review.

OBJECTIVE: To conduct a systematic review and, where possible, quantitative meta-analysis of the existing evidence regarding the therapeutic efficacy and safety of the saw palmetto plant extract, Serenoa repens, in men with symptomatic benign prostatic hyperplasia (BPH). DATA SOURCES: Studies were identified through the search of MEDLINE (1966-1997), EMBASE, Phytodok, the Cochrane Library, bibliographies of identified trials and review articles, and contact with relevant authors and drug companies. STUDY SELECTION: Randomized trials were included if participants had symptomatic BPH, the intervention was a preparation of S repens alone or in combination with other phytotherapeutic agents, a control group received placebo or other pharmacological therapies for BPH, and the treatment duration was at least 30 days. DATA EXTRACTION: Two investigators for each article (T.J.W., A.I., G.S., and R.M.) independently extracted key data on design features, subject characteristics, therapy allocation, and outcomes of the studies. DATA SYNTHESIS: A total of 18 randomized controlled trials involving 2939 men met inclusion criteria and were analyzed. Many studies did not report results in a method that permitted meta-analysis. Treatment allocation concealment was adequate in 9 studies; 16 were double-blinded. The mean study duration was 9 weeks (range, 4-48 weeks). As compared with men receiving placebo, men treated with S repens had decreased urinary tract symptom scores (weighted mean difference [WMD], -1.41 points [scale range, 0-19] [95% confidence interval (CI), -2.52 to -0.30] [n = 1 study]), nocturia (WMD, -0.76 times per evening [95% CI, -1.22 to -0.32] [n = 10 studies]), and improvement in self-rating of urinary tract symptoms; risk ratio for improvement (1.72 [95% CI, 1.21-2.44] [n = 6 studies]), and peak urine flow (WMD, 1.93 mL/s [95% CI, 0.72-3.14] [n = 8 studies]). Compared with men receiving finasteride, men treated with S repens had similar improvements in urinary tract symptom scores (WMD, 0.37 International Prostate Symptom Score points [scale range, 0-35] [95% CI, -0.45 to 1.19] [n = 2 studies]) and peak urine flow (WMD, -0.74 mL/s [95% CI, -1.66 to 0.18] [n = 2 studies]). Adverse effects due to S repens were mild and infrequent; erectile dysfunction was more frequent with finasteride (4.9%) than with S repens (1.1%; P<.001). Withdrawal rates in men assigned to placebo, S repens, or finasteride were 7%, 9%, and 11%, respectively. CONCLUSIONS: The existing literature on S repens for treatment of BPH is limited in terms of the short duration of studies and variability in study design, use of phytotherapeutic preparations, and reports of outcomes. However, the evidence suggests that S repens improves urologic symptoms and flow measures. Compared with finasteride, S repens produces similar improvement in urinary tract symptoms and urinary flow and was associated with fewer adverse treatment events. Further research is needed using standardized preparations of S repens to determine its long-term effectiveness and ability to prevent BPH complications.

Enzyme Inhibitors↗
PubMed2005

Estimated impact of the Prostate Cancer Prevention Trial on population mortality.

BACKGROUND: The potential public health impact of the recently completed Prostate Cancer Prevention Trial (PCPT) is debated. The results indicated that the period prevalence of prostate cancer was reduced by 24.8% due to finasteride, whereas an increase in the rate of high-grade tumors (Gleason score 8-10) among men who were diagnosed with cancer also was found (5.0% in the PCPT placebo arm vs. 11.9% in the PCPT finasteride arm). Whether the increased Gleason score was valid or was a histologic artifact is under investigation. METHODS: The authors estimated the number of person-years saved assuming a 24.8% reduction in the incidence of prostate cancer for 5 years among United States males age > or = 55 years. Scenarios for different proportions of patients with high-grade Gleason scores also were considered. RESULTS: With a 24.8% reduction in the number of men with newly diagnosed prostate cancer, the authors estimated that 316,760 person-years would be saved due to finasteride in the United States. An absolute increase of 6.9% in the proportion of men with high-grade tumors in the United States cancer population (corresponding to the difference between the rates on the placebo and finasteride arms of the PCPT) would reduce the number of person-years saved to 262,567. For each absolute increase of 5% in the proportion of patients with high-grade tumors, the number of person-years saved would be reduced by approximately 39,000. CONCLUSIONS: The results of the PCPT may have a major impact on population mortality from prostate cancer if they are applied clinically. The potential detrimental effects of an increased rate of patients who have prostate cancer with high-grade Gleason scores would be outweighed by a reduction in incidence.

Finasteride↗
PubMed1995

Quantitative evaluation of glandular and stromal compartments in hyperplastic dog prostates: effect of 5-alpha reductase inhibitors.

The objective of this study was to determine the effects of 2 different 5-alpha reductase inhibitors (finasteride and MK-0434) on the glandular and stromal compartments of hyperplastic canine prostates. In this study, dogs received 1 of the 2 compounds orally, at a dose of 1 mg/kg/day for 16 weeks; control dogs received a placebo. The morphological changes in the glandular and stromal compartments in the prostate were quantitated by a point-counting method on Masson's trichrome-stained sections. Treatment with 5-alpha reductase inhibitors resulted in significant (P < or = 0.05) decreases in mean prostatic volumes, microscopic evidence of prostatic atrophy, and significant (P < or = 0.05) decreases in the absolute volumes of the prostatic glandular and stromal compartments compared to controls. In finasteride-treated dogs, the mean percent change from baseline was: epithelium, -52; lumens, -58; fibrovascular stroma, -41; and smooth muscle, -29. In MK-0434-treated dogs, the mean percent change from baseline was: epithelium, -77; lumens, -58; fibrovascular stroma, -38; and smooth muscle, -42. The effect on the glandular compartment in dogs treated with MK-0434 was slightly greater than in dogs treated with finasteride; however, the effect on the stroma was similar. These results clearly demonstrate that inhibition of 5-alpha reductase enzyme activity affects growth and maintenance of both glandular and stromal compartments of dog hyperplastic prostates. It is likely that the decrease in size of the prostate in finasteride-treated (Proscar) men is due to shrinkage of both glandular and stromal compartments.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1990

External genitalia of the rat: normal development and the histogenesis of 5 alpha-reductase inhibitor-induced abnormalities.

The normal histogenesis of the rat genital tubercle and the effect of exposure in utero to the 5 alpha-reductase inhibitor finasteride (L-652,931; MK-0906; Proscar) on that process were studied. In normal males and females, the genital tubercle was first seen on Day 14.25 of gestation. It contained a urethral plate which extended from the cloaca (and after Day 15.25, from the urogenital sinus) to the tip of the tubercle. On Day 18.25 the glans lamellae, which would separate the glans penis or the clitoris from the prepuce, began to develop in both sexes. Also on Day 18.25 a dense, midline plate of mesenchymal cells was first evident between the urogenital sinus and the rectum in normal males. This plate acted as a wedge, first increasing the separation between the rectum and the urogenital sinus, and subsequently separating the urethral plate from the surface epithelium in the genital tubercle. As a result, by Day 21.25 the urethra in males followed an "S"-shaped course, extending from the pelvis through the center of the glans penis to an orifice near the tip of the genital tubercle. In females, in which a mesenchymal plate did not develop, the urethral orifice remained at the base of the tubercle, and the clitoris contained the remnants of the urethral plate, extending as an open groove from the urethral orifice to the tip of the tubercle. Finasteride did not affect development of the genital tubercle in females. However, in males exposed to finasteride in utero, there was variable failure of the mesenchymal wedge to develop. As a result, the urethral plate remained in contact with the surface epithelium and eventually opened to form a groove on the ventral surface of the glans penis (hypospadias). Also, the persistence of the urethral plate along the ventral midline in finasteride-treated male fetuses and its subsequent opening as a groove interfered with development of the glans lamellae, causing displacement of the frenulum distally on the glans penis and the development of a cleft in the prepuce.

Androstenes↗
PubMed2002

Changes in progesterone metabolites in the hippocampus can modulate open field and forced swim test behavior of proestrous rats.

The purpose of these experiments was to test the hypothesis that attenuating the endogenous increase of the 5alpha-reduced progesterone metabolite 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP) in the hippocampus will alter anxiety and depression behavior of proestrous rats. In Experiment 1, anxiety (open field) and depression (forced swim test) behavior was compared of rats that should have high (proestrous) and low (diestrous and male rats) endogenous hippocampal 3alpha,5alpha-THP. Proestrous rats exhibited more anxiolytic-like (increased central entries in the open field) and anti-depressant-like (less immobility in the forced swim test) behavior than diestrous or male rats. In Experiments 2 and 3, respectively, systemic and intrahippocampal finasteride, a 5alpha-reductase inhibitor which attenuates progesterone's metabolism to 3alpha,5alpha-THP, versus vehicle administration to proestrous rats was compared for effects on open field and forced swim test behavior. Systemic or intrahippocampal finasteride decreased central entries in the open field and increased immobility in the forced swim tests compared to vehicle administration. In Experiment 4, the effects of systemic and intrahippocampal finasteride vs vehicle administration on hippocampal 3alpha,5alpha-THP of proestrous rats was examined. Finasteride, SC or intrahippocampally, reduced 3alpha,5alpha-THP in the hippocampus compared to vehicle administration. Together these data suggest that variations in 3alpha,5alpha-THP levels in the hippocampus may mitigate proestrous changes in anxiety and depressive behavior of cycling rats.

Animals↗
PubMed2006

Lack of evidence of a role for the neurosteroid allopregnanolone in ethanol-induced reward and c-fos expression in DBA/2 mice.

Previous studies using the 5alpha-reductase inhibitor finasteride suggest that progesterone metabolites, particularly the endogenous neurosteroid allopregnanolone, mediate some of the effects of ethanol. Consequently, we studied the effect of finasteride (2 x 25 mg/kg s.c., 12 h apart) pretreatment on the acquisition and expression of ethanol (2 g/kg i.p.) induced conditioned place preference and c-fos expression in DBA/2 mice; a strain known to be particularly sensitive to ethanol. Ethanol administration induced a clear conditioned place preference and widespread c-fos expression, with elements of the extended amygdala, Edinger-Westphal nucleus and paraventricular nucleus being especially sensitive. However, despite an approximately 99% decrease in whole brain allopregnanolone content, finasteride pretreatment had remarkably little effect on either ethanol-induced conditioned place preference or ethanol-induced c-fos expression. Thus, aside from a general stimulatory effect on c-fos expression in the ventral tegmental area, and generally mild depression of locomotor activity, no other effects of finasteride or interaction with ethanol effects were identifiable. Together, these studies suggest that endogenous allopregnanolone plays little part in mediating acute ethanol-induced reward or neural activation in DBA/2 mice.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2006

Pharmacokinetic parameters as a potential predictor of response to pharmacotherapy in benign prostatic hyperplasia: a preclinical trial using dynamic contrast-enhanced MRI.

We sought to assess the possibility of using pharmacokinetic parameters as a predictor of response to benign prostatic hyperplasia (BPH) pharmacotherapy via a randomized, placebo-controlled, animal preclinical trial using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Twelve male beagles with BPH were enrolled in a preclinical experimental drug trial and divided into two randomized groups with six beagles each: one drug (finasteride) group and one placebo (control) group. Two baseline MRI examinations and three follow-ups during treatment were performed on a clinical 1.5-T MRI system using axial T1- and T2-weighted magnetic resonance images for prostate volume measurement and DCE-MRI for the assessment of prostate microcirculation. A total of 0.2 mmol/kg body weight of the Gd-based contrast agent was administered with an injection rate of 0.2 ml/s. The pharmacokinetic parameters, maximum enhancement ratio (MER), transfer constant and rate constant, were assessed to characterize the microcirculation in the parenchymal zone. The time-signal intensity curve from the external iliac artery was used as the arterial input function. The correlation between baseline evaluations (prostate volume and pharmacokinetic parameters) and therapy-induced prostate volume changes under finasteride treatment were assessed. The changes in prostate volume at the end of the trial exhibited a significant linear correlation to the initial parenchymal MER (P < .02) in the finasteride group. Larger prostate volume reductions coincided with smaller initial parenchymal MER. These findings show considerable promise of using parenchymal MER as a predictor of response to BPH pharmacotherapy with finasteride.

Animals↗
PubMed2006

Geographic variations in the use of medical and surgical therapies for benign prostatic hyperplasia.

PURPOSE: Patients with BPH have several treatment options. Little is known about geographic variations in surgical rates for BPH and the market relationships to medical therapy, health resources and sociodemographic factors. MATERIALS AND METHODS: We conducted a cross-sectional study using administrative data from 5 states in 2000. Rates of surgical and medical therapy were calculated per 100,000 men 55 years old or older. Main outcome measures were county level weighted coefficient of variation and systematic component of variation in therapy rates, as well as surgery rates as a function of medication dispensing rates, health care resources and sociodemographic characteristics. RESULTS: North Carolina had the lowest surgery rates (26.3 minimally invasive procedures and 332.1 invasive surgeries per 100,000) and finasteride dispensing rates (503.5 per 100,000). Overall rates of medical therapy were 5 times higher than surgery rates. Geographic variations in surgical and medical therapy rates were significant for each state, and North Carolina had the greatest variation. An increase of 11.6 per 100,000 (95% CI, 6.5-55.8) in annual county level finasteride dispensing would be associated with a decrease in the surgery rate of 1 per 100,000, controlling for other variables. CONCLUSIONS: There is significant systematic variation in rates of surgical and medical therapy for BPH at county and state levels. The relationship between finasteride and surgery in randomized clinical trials is generalizable to the marketplace. Finasteride rates are inversely related to surgery rates, and tamsulosin rates are positively associated with surgery rates. Surgery rates are not significantly associated with urologists per capita.

Adrenergic alpha-Antagonists↗
PubMed2003

Effect of a novel steroid (PM-9) on the inhibition of 5alpha-reductase present in Penicillium crustosum broths.

The conversion of testosterone (T) to 5alpha-dihydrotestosterone (DHT) has been demonstrated in Penicillium crustosum broth obtained from fermented pistachios, lemons and corn tortillas. Furthermore, the presence of 5alpha-reductase enzyme, which is responsible for this conversion, has been established by electrophoretical techniques in these cultures.5alpha-Reductase enzyme is also present in animal and human androgen-dependent tissues as well as in prostate and seminal vesicles. The increase of the conversion of T to DHT in prostate gland, has been related to some illnesses such as benign prostate hyperplasia and prostate cancer. Furthermore, treatment with 5alpha-reductase inhibitors such as finasteride reduces the prostate growth. These data have stimulated research for the synthesis of new molecules with antiandrogenic activity, whose biological effect needs to be demonstrated. The purpose of this study is to determine the inhibition pattern of 5alpha-reductase in P. crustosum by finasteride and the new steroidal compound PM-9. K(m) and V(max) values for T, were determined in the broths by Lineweaver-Burk plots using different testosterone concentrations. The inhibition pattern of finasteride and PM-9 was also determined by Lineweaver-Burk using different concentrations of T and inhibitors. Results show that finasteride and PM-9 inhibit 5alpha-reductase present in the broth in a competitive manner.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2002

Reporting of acute urinary retention in BPH treatment trials: importance of patient follow-up after discontinuation and case definitions.

OBJECTIVES: A growing number of reports of retrospective analyses of adverse events occurring during studies with alpha-blockers in men with benign prostatic hyperplasia (BPH) have compared acute urinary retention (AUR) event rates with placebo-controlled finasteride trials. Because of differences in study designs, the present analysis was undertaken to compare data on the rates of AUR across different BPH trials accurately. METHODS: We report the incidence of spontaneous AUR for placebo, finasteride, and alpha-blockers based on published data in randomized clinical trials in men with BPH. RESULTS: On the basis of the data from all published randomized finasteride and alpha-blocker studies reporting AUR, the overall incidence rate for spontaneous AUR during active treatment with placebo, alpha-blockers, and finasteride ranged from 0.9 to 5.2, 0 to 1.2, and 0.3 to 1.2, respectively. The only study to provide data on AUR occurring during post-treatment follow-up was the Proscar Long-Term Efficacy and Safety Study (PLESS), in which approximately 25% of events occurred in patients after they had discontinued the study. Several of the alpha-blocker studies had significantly shorter durations, relatively small patient populations with smaller prostate volumes, lower numbers of events reported, and higher discontinuation rates with no follow-up, all of which could tremendously affect the reporting of AUR. Additionally, only PLESS reported on both spontaneous and precipitated AUR. CONCLUSIONS: Simply comparing the reported rates of AUR from published studies without taking into consideration spontaneous versus precipitated AUR, discontinuation rates, total patient follow-up, and prostate volume does not adequately allow for comparison of the true event rate across different clinical trials.

Acute Disease↗