5α-reductases in human physiology: an unfolding story

Sex steroid hormone synthesis, metabolism, and the effects on the mammalian olfactory system

Sex steroid hormones influence olfactory-mediated social behaviors, and it is generally hypothesized that these effects result from circulating hormones and/or neurosteroids synthesized in the brain. However, it is unclear whether sex steroid hormones are synthesized in the olfactory epithelium or the olfactory bulb, and if they can modulate the activity of the olfactory sensory neurons. Here, we review important discoveries related to the metabolism of sex steroids in the mouse olfactory epithelium and olfactory bulb, along with potential areas of future research. We summarize current knowledge regarding the expression, neuroanatomical distribution, and biological activity of the steroidogenic enzymes, sex steroid receptors, and proteins that are important to the metabolism of these hormones and reflect on their potential to influence early olfactory processing. We also review evidence related to the effects of sex steroid hormones on the development and activity of olfactory sensory neurons. By better understanding how these hormones are metabolized and how they act both at the periphery and olfactory bulb level, we can better appreciate the complexity of the olfactory system and discover potential similarities and differences in early olfactory processing between sexes.

Androgen Effects on Neural Plasticity

Androgens are synthesized in the brain, gonads, and adrenal glands, in both sexes, exerting physiologically important effects on the structure and function of the central nervous system. These effects may contribute to the incidence and progression of neurological disorders such as autism spectrum disorder, schizophrenia, and Alzheimer's disease, which occur at different rates in males and females. This review briefly summarizes the current state of knowledge with respect to the neuroplastic effects of androgens, with particular emphasis on the hippocampus, which has been the focus of much of the research in this field.

A Network Pharmacology to Explore the Mechanism of Calculus Bovis in the Treatment of Ischemic Stroke

BACKGROUND

Calculus Bovis is a valuable Chinese medicine, which is widely used in the clinical treatment of ischemic stroke. The present study is aimed at investigating its target and the mechanism involved in ischemic stroke treatment by network pharmacology.

METHODS

Effective compounds of Calculus Bovis were collected using methods of network pharmacology and using the Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese Medicine (BATMAN-TCM) and the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP). Potential compound targets were searched in the TCMSP and SwissTargetPrediction databases. Ischemic stroke-related disease targets were searched in the Drugbank, DisGeNet, OMIM, and TTD databases. These two types of targets were uploaded to the STRING database, and a network of their interaction (PPI) was built with its characteristics calculated, aiming to reveal a number of key targets. Hub genes were selected using a plug-in of the Cytoscape software, and Gene Ontology (GO) biological processes and pathway enrichment analyses of Kyoto Encyclopedia of Genes and Genomes (KEGG) were conducted using the clusterProfiler package of R language.

RESULTS

Among 12 compounds, deoxycorticosterone, methyl cholate, and biliverdin were potentially effective components. A total of 344 Calculus Bovis compound targets and 590 ischemic stroke targets were found with 92 overlapping targets, including hub genes such as TP53, AKT, PIK2CA, MAPK3, MMP9, and MMP2. Biological functions of Calculus Bovis are associated with protein hydrolyzation, phosphorylation of serine/threonine residues of protein substrates, peptide bond hydrolyzation of peptides and proteins, hydrolyzation of intracellular second messengers, antioxidation and reduction, RNA transcription, and other biological processes.

CONCLUSION

Calculus Bovis may play a role in ischemic stroke by activating PI3K-AKT and MAPK signaling pathways, which are involved in regulating inflammatory response, cell apoptosis, and proliferation.

Cognitive Function and Urologic Medications for Lower Urinary Tract Symptoms

Special considerations should be made when selecting medications for the treatment of lower urinary tract symptoms (LUTS) in older patients especially those over 65 years old. This review summarizes the relationship between current treatments for LUTS and cognitive impairment. Although the recently reported association between dementia and tamsulosin is debatable, the effects of α-blockers and pharmacokinetics are not reported in this context. Five-alpha reductase inhibitors appear to affect mood. However, the association between the development of dementia and cognitive impairment is unlikely. Anticholinergic agents, other than trospium, fesoterodine, and imdafenacin have a relatively high distribution in the central nervous system. In particular, oxybutynin is reported to cause cognitive impairment. Several animal studies on the blood-brain barrier permeability of oxybutynin support this. Therefore, care must be taken when they are used in older patients (65 years and older). Beta-3 agonists are an alternative to, or may be used in combination with, anticholinergic drugs for patients with an overactive bladder (OAB). Several phase 2 and 3 clinical studies report high tolerability and efficacy, making them relatively safe for OAB treatment. However, there is a possibility that cognitive function may be affected; thus, long-term study data are required. We have reviewed studies investigating the correlation of urologic medications with cognitive dysfunction and have provided an overview of drug selection, as well as other considerations in older patients (65 years and older) with LUTS. This narrative review has focused primarily on articles indexed in PubMed, Google Scholar, Scopus, and Embase databases. No formal search strategy was used, and no meta-analysis of data was performed.

Post-finasteride syndrome: a surmountable challenge for clinicians

Post-finasteride syndrome (PFS) is a constellation of serious adverse side effects manifested in clinical symptoms that develop and persist in patients during and/or after discontinuing finasteride treatment in men with pattern hair loss (androgenetic alopecia) or benign prostatic hyperplasia. These serious adverse side effects include persistent or irreversible sexual, neurological, physical and mental side effects. To date, there are no evidence-based effective treatments for PFS. Although increasing number of men report persistent side effects, the medical community has yet to recognize this syndrome nor are there any specific measures to address this serious and debilitating symptoms. Here we evaluate the scientific and clinical evidence in the contemporary medical literature to address the very fundamental question: Is PFS a real clinical condition caused by finasteride use or are the reported symptoms only incidentally associated with but not caused by finasteride use? One key indisputable clinical evidence noted in all reported studies with finasteride and dutasteride was that use of these drugs is associated with development of sexual dysfunction, which may persist in a subset of men, irrespective of age, drug dose or duration of study. Also, increased depression, anxiety and suicidal ideation in a subset of men treated with these drugs were commonly reported in a number of studies. It is important to note that many clinical studies suffer from incomplete or inadequate assessment of adverse events and often limited or inaccurate data reporting regarding harm. Based on the existing body of evidence in the contemporary clinical literature, the author believes that finasteride and dutasteride induce a constellation of persistent sexual, neurological and physical adverse side effects, in a subset of men. These constellations of symptoms constitute the basis for PFS in individuals predisposed to epigenetic susceptibility. Indeed, delineating the pathophysiological mechanisms underlying PFS will be of paramount importance to the understanding of this syndrome and to development of potential novel therapeutic modalities.

The Association of 5α-Reductase Inhibitor With Suicidality

OBJECTIVE

Using a large nationwide cohort, this study aimed to determine the risk of suicide after the use of a 5α-reductase inhibitor, an antiandrogenic medication commonly used in the treatment of lower urinary tract symptoms.

METHODS

A retrospective population-based cohort study was performed using the Korean National Health Insurance Service database. The study consisted of 51,466 men 60 years or older who underwent health examinations between 2005 and 2006. Individuals using a 5α-reductase inhibitor were compared with nonusers based on drug exposure between 2003 and 2006. Individuals using a 5α-reductase inhibitor were additionally divided into tertiles based on cumulative 5α-reductase inhibitor exposure. The incidence of completed suicide was documented during 7 years of follow-up, starting January 1, 2007.

RESULTS

No significant risk of suicide was observed among 5α-reductase inhibitor users compared with 5α-reductase inhibitor nonusers (hazard ratio = 1.02, 95% confidence interval = 0.70-1.48). Cumulative 5α-reductase inhibitor exposure was also not associated with increased risk of suicide (p for trend = .543).

CONCLUSIONS

5α-Reductase inhibitor use was not associated with an elevated risk of suicide during a long-term follow-up period. A limitation of this study is that possible drug exposure after the index date was not accounted for. Although 5α-reductase inhibitor may increase the risk of depressive symptoms, the present data indicate that the drug is safe in terms of long-term suicide risk.

Health Risks Associated with Long-Term Finasteride and Dutasteride Use: It's Time to Sound the Alarm

5α-dihydrotestosterone (5α-DHT) is the most potent natural androgen. 5α-DHT elicits a multitude of physiological actions, in a host of tissues, including prostate, seminal vesicles, hair follicles, skin, kidney, and lacrimal and meibomian glands. However, the physiological role of 5α-DHT in human physiology, remains questionable and, at best, poorly appreciated. Recent emerging literature supports a role for 5α-DHT in the physiological function of liver, pancreatic β-cell function and survival, ocular function and prevention of dry eye disease and kidney physiological function. Thus, inhibition of 5α-reductases with finasteride or dutasteride to reduce 5α-DHT biosynthesis in the course of treatment of benign prostatic hyperplasia (BPH) or male pattern hair loss, known as androgenetic alopecia (AGA) my induces a novel form of tissue specific androgen deficiency and contributes to a host of pathophysiological conditions, that are yet to be fully recognized. Here, we advance the concept that blockade of 5α-reductases by finasteride or dutasteride in a mechanism-based, irreversible, inhabitation of 5α-DHT biosynthesis results in a novel state of androgen deficiency, independent of circulating testosterone levels. Finasteride and dutasteride are frequently prescribed for long-term treatment of lower urinary tract symptoms in men with BPH and in men with AGA. This treatment may result in development of non-alcoholic fatty liver diseases (NAFLD), insulin resistance (IR), type 2 diabetes (T2DM), dry eye disease, potential kidney dysfunction, among other metabolic dysfunctions. We suggest that long-term use of finasteride and dutasteride may be associated with health risks including NAFLD, IR, T2DM, dry eye disease and potential kidney disease.

Risk of Depression after 5 Alpha Reductase Inhibitor Medication: Meta-Analysis

PURPOSE

Although five-alpha reductase inhibitor (5-ARI) is one of standard treatment for benign prostatic hyperplasia (BPH) or alopecia, potential complications after 5-ARI have been issues recently. This study aimed to investigate the risk of depression after taking 5-ARI and to quantify the risk using meta-analysis.

MATERIALS AND METHODS

A total of 209,940 patients including 207,798 in 5-ARI treatment groups and 110,118 in control groups from five studies were included for final analysis. Inclusion criteria for finial analysis incudes clinical outcomes regarding depression risk in BPH or alopecia patients. Overall hazard ratio (HR) and odds ratio (OR) for depression were analyzed. Moderator analysis and sensitivity analysis were performed to determine whether HR or OR could be affected by any variables, including number of patients, age, study type, and control type.

RESULTS

The pooled overall HRs for the 5-ARI medication was 1.23 (95% confidence interval [CI], 0.99-1.54) in a random effects model. The pooled overall ORs for the 5-ARI medication was 1.19 (95% CI, 0.95-1.49) in random effects model. The sub-group analysis showed that non-cohort studies had higher values of HR and OR than cohort studies. Moderator analysis using meta-regression showed that there were no variables that affect the significant difference in HR and OR outcomes. However, in sensitivity analysis, HR was significantly increased by age (p=0.040).

CONCLUSIONS

Overall risk of depression after 5-ARI was significantly not high, however its clinical importance needs validation by further studies. These quantitative results could provide useful information for both clinicians and patients.

Do 5α-Reductase Inhibitors Raise Circulating Serum Testosterone Levels? A Comprehensive Review and Meta-Analysis to Explaining Paradoxical Results

INTRODUCTION

Many studies have reported that 5α-reductase inhibitors (finasteride and dutasteride) raise serum testosterone (T) levels, yet there is lack of consistency among studies on this point.

AIM

To review and meta-analyze available studies reporting changes in serum T concentrations in men treated with 5α-reductase inhibitors (5α-RIs).

METHODS

A Medline search using PubMed and EMBASE was performed including the following key words: "finasteride," "dutasteride," "testosterone and 5α-reductases."

MAIN OUTCOME MEASURE

Relevant studies were extracted, evaluated, and analyzed. Of these, 40 studies were analyzed qualitatively and 11 were included in the meta-analysis. A random effects model was used to conduct the meta-analysis.

RESULTS

In 11 studies comprising 1,784 patients with age ranging between 18 and 83 years and average treatment follow-up of 17 months, meta-analytic estimate of the mean baseline change was 27 (95% confidence interval 1-54). The meta-analysis did not demonstrate unequivocal significant increase in serum T levels. The increase was not uniform among all studies reported. Sensitivity analysis showed that no single study contributed decisively to the outcome or could be attributed to drug action. The reported increases in T levels with finasteride or dutasteride in men with low baseline serum T may be attributed, in part, to increased trapping of T by unsaturated sex hormone binding globulin (SHBG) due to dissociation of 5α-dihydrotestosterone. In men with high baseline T levels, there appears to be no change in serum T levels. 10 studies reported luteinizing hormone, follicle-stimulating hormone, SHBG, and estradiol values and none reported significant changes in their levels, suggesting that observed changes in serum T levels are unlikely mediated by gonadotropins levels or peripheral conversion of T to estradiol.

CONCLUSION

5α-RI therapy is not associated with consistent and significant increases in serum T levels. Traish AM, Krakowsky Y, Doros G, et al. Do 5α-reductase inhibitors raise circulating serum testosterone levels? A comprehensive review and meta-analysis to explaining paradoxical results. Sex Med Rev 2019;7:95-114.

Finasteride and Erectile Dysfunction in Patients with Benign Prostatic Hyperplasia or Male Androgenetic Alopecia

Finasteride is primarily used to treat benign prostatic hyperplasia (BPH) and male androgenetic alopecia (MAA). Five-alpha reductase inhibitors (5α-RIs) could induce male sexual dysfunction due to their effects on testosterone and dihydrotestosterone. There is evidence suggesting that 5α-RIs may independently increase the risk of erectile dysfunction (ED). However, many investigators believe that side effects of 5α-RIs will disappear with continuous treatment. Considerable controversy exists regarding the severity and persistence of side effects of finasteride on ED. The aim of this review was to summarize current research studies on finasteride associated with ED. The search strategy used each term of finasteride and ED against PubMed database to identify related studies. ED data reported from available trials for finasteride were summarized and reviewed. Although there is not enough evidence to prove the relationship between finasteride and ED, most studies in this review found that finasteride for BPH was correlated with ED. However, most studies included in this review revealed that finasteride for MAA was not correlated with ED. On the other hand, some studies reported side effects of finasteride associated with sexual dysfunction, including ED, male infertility, ejaculation problem, and loss of libido, even in MAA patients. Well-designed randomized controlled trials are needed to further determine the mechanism and effects of finasteride on ED. However, physicians should discuss with their patients possible long-term effects of finasteride on sexual function, although we do not have evidence showing that adverse events of sexual dysfunction are absolutely associated with 5α-RIs.

Post-finasteride syndrome and post-SSRI sexual dysfunction: two sides of the same coin?

Sexual dysfunction is a clinical condition due to different causes including the iatrogenic origin. For instance, it is well known that sexual dysfunction may occur in patients treated with antidepressants like selective serotonin reuptake inhibitors (SSRI). A similar side effect has been also reported during treatment with finasteride, an inhibitor of the enzyme 5alpha-reductase, for androgenetic alopecia. Interestingly, sexual dysfunction persists in both cases after drug discontinuation. These conditions have been named post-SSRI sexual dysfunction (PSSD) and post-finasteride syndrome (PFS). In particular, feeling of a lack of connection between the brain and penis, loss of libido and sex drive, difficulty in achieving an erection and genital paresthesia have been reported by patients of both conditions. It is interesting to note that the incidence of these diseases is probably so far underestimated and their etiopathogenesis is not sufficiently explored. To this aim, the present review will report the state of art of these two different pathologies and discuss, on the basis of the role exerted by three different neuromodulators such as dopamine, serotonin and neuroactive steroids, whether the persistent sexual dysfunction observed could be determined by common mechanisms.

Corni Fructus attenuates testosterone-induced benign prostatic hyperplasia by suppressing 5α-reductase and androgen receptor expression in rats

BACKGROUND/OBJECTIVES

Benign prostatic hypertrophy (BPH) is a major cause of abnormal overgrowth of the prostate mainly in the elderly. Corni Fructus has been reported to be effective in the prevention and treatment of various diseases because of its strong antioxidant effect, but its efficacy against BPH is not yet known. This study was designed to evaluate the therapeutic efficacy of Corni Fructus water extract (CF) in testosterone-induced BPH rats.

MATERIALS/METHODS

To induce BPH, rats were intraperitoneal injected with testosterone propionate (TP). Rats in the treatment group were orally administered with CF with TP injection, and finasteride, which is a selective inhibitor of 5α-reductase type 2, was used as a positive control.

RESULTS

Our results showed that the increased prostate weight and histopathological changes in BPH model rats were suppressed by CF treatment. CF, similar to the finasteride-treated group, decreased the levels of testosterone and dihydrotestosterone by TP treatment in the serum, and it also reduced 5α-reductase expression and concentration in prostate tissue and serum, respectively. In addition, CF significantly blocked the expression of the androgen receptor (AR), AR co-activators, and proliferating cell nuclear antigen in BPH rats, and this blocking was associated with a decrease in prostate-specific antigen levels in serum and prostate tissue.

CONCLUSIONS

These results suggest that CF may weaken the BPH status through the inactivation of at least 5α-reductase and AR activity and may be useful for the clinical treatment of BPH.

Risk of rhabdomyolysis from 5-α reductase inhibitors

PURPOSE

A recent regulatory warning and case reports have described the development of muscle complications with the use of 5-α reductase inhibitors (5ARIs). We wished to determine if there was a link between rhabdomyolysis and 5ARI usage.

METHODS

We used a matched cohort design and linked administrative data from the province of Ontario, Canada, to investigate the risk of rhabdomyolysis in men using either finasteride or dutasteride. A total of 99 covariates were measured. We identified 93 197 men ≥66 years of age who initiated a new prescription for a 5ARI, and they were matched using a propensity score to an equal number of men not prescribed a 5ARI.

RESULTS

New initiation of 5ARIs was not associated with a significantly increased risk of rhabdomyolysis (hazard ratio [HR] 1.21, 95% confidence interval [CI], 1.00-1.48, P = .06). When we examined the risk of rhabdomyolysis in the year prior to the initiation of a 5ARI, we found that men who would go on to use a 5ARI in the future had an elevated risk of rhabdomyolysis even prior to starting the medication (HR 1.31, 95% CI, 1.05-1.64, P = .01). Our secondary outcome of myositis and myopathy was significantly higher among 5ARI users (HR 1.63, 95% CI, 1.48-1.80, P < .01), and this risk was not present prior to 5ARI usage.

CONCLUSION

5-α reductase inhibitors do not appear to be associated with the development of rhabdomyolysis; however, they may be associated with an increased risk of myopathy and myositis.

Overview of the Molecular Steps in Steroidogenesis of the GABAergic Neurosteroids Allopregnanolone and Pregnanolone

Allopregnanolone and pregnanolone-neurosteroids synthesized from progesterone in the brain, adrenal gland, ovary and testis-have been implicated in a range of neuropsychiatric conditions including seizure disorders, post-traumatic stress disorder, major depression, post-partum depression, pre-menstrual dysphoric disorder, chronic pain, Parkinson's disease, Alzheimer's disease, neurotrauma, and stroke. Allopregnanolone and pregnanolone equipotently facilitate the effects of gamma-amino-butyric acid (GABA) at GABAA receptors, and when sulfated, antagonize N-methyl-D-aspartate receptors. They play myriad roles in neurophysiological homeostasis and adaptation to stress while exerting anxiolytic, antidepressant, anti-nociceptive, anticonvulsant, anti-inflammatory, sleep promoting, memory stabilizing, neuroprotective, pro-myelinating, and neurogenic effects. Given that these neurosteroids are synthesized de novo on demand, this review details the molecular steps involved in the biochemical conversion of cholesterol to allopregnanolone and pregnanolone within steroidogenic cells. Although much is known about the early steps in neurosteroidogenesis, less is known about transcriptional, translational, and post-translational processes in allopregnanolone- and pregnanolone-specific synthesis. Further research to elucidate these mechanisms as well as to optimize the timing and dose of interventions aimed at altering the synthesis or levels of these neurosteroids is much needed. This should include the development of novel therapeutics for the many neuropsychiatric conditions to which dysregulation of these neurosteroids contributes.

Neuroactive steroid levels and psychiatric and andrological features in post-finasteride patients

Recent reports show that, in patients treated with finasteride for male pattern hair loss, persistent side effects including sexual side effects, depression, anxiety and cognitive complaints may occur. We here explored the psychiatric and andrological features of patients affected by post-finasteride syndrome (PFS) and verified whether the cerebrospinal fluid (CSF) and plasma levels of neuroactive steroids (i.e., important regulators of nervous function) are modified. We found that eight out of sixteen PFS male patients considered suffered from a DSM-IV major depressive disorder (MDD). In addition, all PFS patients showed erectile dysfunction (ED); in particular, ten patients showed a severe and six a mild-moderate ED. We also reported abnormal somatosensory evoked potentials of the pudendal nerve in PFS patients with severe ED, the first objective evidence of a neuropathy involving peripheral neurogenic control of erection. Testicular volume by ultrasonography was normal in PFS patients. Data obtained on neuroactive steroid levels also indicate interesting features. Indeed, decreased levels of pregnenolone, progesterone and its metabolite (i.e., dihydroprogesterone), dihydrotestosterone and 17beta-estradiol and increased levels of dehydroepiandrosterone, testosterone and 5alpha-androstane-3alpha,17beta-diol were observed in CSF of PFS patients. Neuroactive steroid levels were also altered in plasma of PFS patients, however these changes did not reflect exactly what occurs in CSF. Finally, finasteride did not only affect, as expected, the levels of 5alpha-reduced metabolites of progesterone and testosterone, but also the further metabolites and precursors suggesting that this drug has broad consequence on neuroactive steroid levels of PFS patients.

Long-term dutasteride therapy in men with benign prostatic hyperplasia alters glucose and lipid profiles and increases severity of erectile dysfunction

Background Dutasteride has been successfully used in treatment of lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). However, dutasteride inhibits 5α-reductase type 1 and type 2 enzymes and may compromises glucocorticoids and androgen metabolism and alters metabolic function resulting in undesirable metabolic and sexual adverse side effects. Aim The aim of this study was to investigate the long-term adverse effects of dutasteride therapy in men with BPH on: i) blood glucose, ii) glycated hemoglobin (HbA1c), iii) low density lipoprotein-cholesterol (LDL-C); high density lipoprotein-cholesterol (HDL-C) and total cholesterol (TC), iv) testosterone (T), v) liver alanine and aspartate aminotransferases (ALT and AST) and vi) erectile dysfunction (ED). Methods A retrospective registry study, with a cohort of 230 men aged between 47 and 68 years (mean 57.78 ± 4.81) were treated with dutasteride (0.5 mg/day) for LUTS, secondary to BPH. A second cohort of 230 men aged between 52 and 72 years (mean 62.62 ± 4.65) were treated with tamsulosin (0.4 mg). All men were followed up for 36-42 months. At intervals of 3-6 months, and at each visit, plasma glucose, HbA1c, TC, LDL-cholesterol, T levels and liver alanine amino transferase (ALT) and aspartate aminotransferase (AST) were determined. Further patient assessment was made by the International Index of Erectile Function (IIEF-EF) questionnaire, the Aging Male Symptom (AMS) and International Prostate Symptom Scores (IPSS). Results Long-term treatment with dutasteride therapy is associated with significant improvements in LUTS, as assessed by reduction in prostate volume, IPSS and prostate specific antigen (PSA). Long-term dutasteride therapy, however, resulted in increased blood glucose, HbA1c, TC and LDL levels, ALT and AST activities, AMS Score and reduced T levels and worsened ED as assessed by the IIEF-EF scores. No worsening of ED, glucose, HbA1c, ALT, AST, AMS were observed in men treated with tamsulosin. Most importantly, long-term dutasteride therapy resulted in reduction in total T levels, contributing to a state of hypogonadism. Conclusion Our findings suggest that long-term dutasteride therapy produces worsening of ED, reduced T levels and increased glucose, HbA1c and alters lipid profiles, suggesting induced imbalance in metabolic function. We strongly recommend that physicians discuss with their patients these potential serious adverse effects of long-term dutasteride therapy prior to instituting this form of treatment.

Dihydrotestosterone: Biochemistry, Physiology, and Clinical Implications of Elevated Blood Levels

Benefits associated with lowered serum DHT levels after 5α-reductase inhibitor (5AR-I) therapy in men have contributed to a misconception that circulating DHT levels are an important stimulus for androgenic action in target tissues (e.g., prostate). Yet evidence from clinical studies indicates that intracellular concentrations of androgens (particularly in androgen-sensitive tissues) are essentially independent of circulating levels. To assess the clinical significance of modest elevations in serum DHT and the DHT/testosterone (T) ratio observed in response to common T replacement therapy, a comprehensive review of the published literature was performed to identify relevant data. Although the primary focus of this review is about DHT in men, we also provide a brief overview of DHT in women. The available published data are limited by the lack of large, well-controlled studies of long duration that are sufficiently powered to expose subtle safety signals. Nonetheless, the preponderance of available clinical data indicates that modest elevations in circulating levels of DHT in response to androgen therapy should not be of concern in clinical practice. Elevated DHT has not been associated with increased risk of prostate disease (e.g., cancer or benign hyperplasia) nor does it appear to have any systemic effects on cardiovascular disease safety parameters (including increased risk of polycythemia) beyond those commonly observed with available T preparations. Well-controlled, long-term studies of transdermal DHT preparations have failed to identify safety signals unique to markedly elevated circulating DHT concentrations or signals materially different from T.

Association of Suicidality and Depression With 5α-Reductase Inhibitors

IMPORTANCE

There have been concerns raised by patients and regulatory agencies regarding serious psychiatric adverse effects associated with 5α-reductase inhibitors.

OBJECTIVE

To determine if there is an increased risk of suicide, self-harm, or depression among older men starting a 5α-reductase inhibitor for prostatic enlargement.

DESIGN, SETTING, AND PARTICIPANTS

A population-based, retrospective, matched cohort study using linked administrative data for 93 197 men ages 66 years or older (median [IQR] age, 75 [70-80] years) in Ontario, Canada, who initiated a new prescription for a 5α-reductase inhibitor during the study period (2003 through 2013). Participants were matched (using a propensity score that included 44 of our 96 covariates that included medical comorbidities, medication usage, and health care system utilization) to an equal number of men not prescribed a 5α-reductase inhibitor.

EXPOSURES

Duration of finasteride or dutasteride usage.

MAIN OUTCOMES AND MEASURES

Suicide. Secondary outcomes were self-harm and depression.

RESULTS

Men who used 5α-reductase inhibitors were not at a significantly increased risk of suicide (HR, 0.88; 95% CI, 0.53-1.45). Risk of self-harm was significantly increased during the initial 18 months after 5α-reductase inhibitor initiation (HR, 1.88; 95% CI, 1.34-2.64), but not thereafter. Incident depression risk was elevated during the initial 18 months after 5α-reductase inhibitor initiation (HR, 1.94; 95% CI, 1.73-2.16), and continued to be elevated, but to a lesser degree, for the remainder of the follow-up period (HR, 1.22; 95% CI, 1.08-1.37). The absolute increases in the event rates for these 2 outcomes were 17 per 100 000 patient-years and 237 per 100 000 patient-years, respectively. The type of 5α-reductase inhibitor (finasteride or dutasteride) did not significantly modify the observed associations with suicide, self-harm, and depression.

CONCLUSIONS AND RELEVANCE

In a large cohort of men ages 66 years or older, we did not demonstrate an increased risk of suicide associated with 5α-reductase inhibitor use. However, the risk of self-harm and depression were increased compared with unexposed men. This is in keeping with postmarketing experience and patient concerns, and discontinuation of the medication in these circ umstances may be appropriate.

Dutasteride-mediated morphological changes in the genitourinary tract associated with altered expression patterns of the androgen and estrogen receptors in male rats

We evaluated the effects of dutasteride on the genitourinary tract using fifteen 8-week-old male Sprague-Dawley rats. Animals were divided into three groups comprising five animals each and treated as follows. Group A was a control group, members of Group B received oral administration of dutasteride 0.1 mg/kg/day from the age of 8 to 16 weeks, and members of Group C were castrated at the age of 8 weeks. All rats were killed at the age of 16 weeks for the sample collection of blood, bladder, prostate, seminal vesicles, and penis. Then, we evaluated the pathological examination for evaluating the tissue fibrosis and hormonal receptor expression. The results showed that the mean size of the prostate and seminal vesicles was smaller in Group B and Group C than in Group A. Serum and tissue concentrations of both testosterone and dihydrotestosterone were remarkably reduced in serum and all tissues in Group C compared with Group A. On the other hand, in Group B, only dihydrotestosterone was reduced in serum and penis. Histopathological examination revealed that Group C showed statistically significant histological changes, such as an increase in fibrotic tissue in the bladder, prostate, and penis. Similarly, Group B showed fibrotic changes in the prostate and penis compared with the Group A. Immunofluorescent staining revealed that the androgen receptor was more strongly expressed than the estrogen receptor beta in Group A. On the other hand, in Group C, weak expression of the androgen receptor and strong expression of the estrogen receptor beta was noted. In Group B, these changes were noted in the prostate and penis. These findings suggest that dutasteride cause morphological changes not only in prostate but also in penis. These changes are associated with altered expression patterns of androgen receptor and estrogen receptor.

Effect of 5α-Reductase Inhibitors on Sexual Function: A Meta-Analysis and Systematic Review of Randomized Controlled Trials

INTRODUCTION

5α-Reductase inhibitors (5ARIs) are widely used for the treatment of benign prostatic hyperplasia (BPH) and androgenetic alopecia (AGA).

AIM

To review all the available data on the effect of 5ARIs on sexual function and assess whether 5ARIs increase the risk of sexual dysfunction.

METHODS

A systematic search of the literature was conducted using the Medline, Embase, and Cochrane databases. The search was limited to articles published in English and up to October 2015. Article selection proceeded according to the search strategy based on Preferred Reporting Items for Systematic Reviews and Meta-analyses criteria. Data were analyzed using Stata 12.0. A fixed- or a random-effects model was used to calculate the overall combined risk estimates. Publication bias was assessed using Begg and Egger tests.

MAIN OUTCOME MEASURES

Sexual dysfunction, erectile dysfunction, and decreased libido.

RESULTS

After screening 493 articles, 17 randomized controlled trials with 17,494 patients were included. Nine studies evaluated the efficacy of 5ARIs in men with BPH. The other eight reported using 5ARIs in the treatment of men with AGA. The mean age of participants was 60.10 years across all studies. We included 10 trials (6,779 patients) on the efficacy and safety of finasteride, 4 trials (6,222 patients) on the safety and tolerability of dutasteride, and 3 trials (4,493 patients) using finasteride and dutasteride for AGA. The pooled relative risks for sexual dysfunction were 2.56 (95% CI = 1.48-4.42) in men with BPH and 1.21 (95% CI = 0.85-1.72) in men with AGA; those for erectile dysfunction were 1.55 (95% CI = 1.14-2.12) in men with BPH and 0.66 (95% CI = 0.20-2.25) in men with AGA; and those for decreased libido were 1.69 (95% CI = 1.03-2.79) in men with BPH and 1.16 (95% CI = 0.50-2.72) in men with AGA. Estimates of the total effects were generally consistent with the sensitivity analysis. No evidence of publication bias was observed.

CONCLUSION

Evidence from the randomized controlled trials suggested that 5ARIs were associated with increased adverse effects on sexual function in men with BPH compared with placebo. However, the association was not statistically significant in men with AGA. Well-designed randomized controlled trials are indicated to study further the mechanism and effects of 5ARIs on sexual function.

Finasteride, not tamsulosin, increases severity of erectile dysfunction and decreases testosterone levels in men with benign prostatic hyperplasia

BACKGROUND

5α-reductase inhibitors (5α-RIs) (finasteride and dutasteride) have been proven useful in treatment of lower urinary tract symptoms (LUTS) related to benign prostatic hyperplasia (BPH). However, these inhibitors exert undesirable sexual side effects and, in some cases, these effects are persistent. There is considerable disagreement with regard to whether the adverse side effects resolve with continuous treatment.

AIM

To investigate the long-term adverse effects of finasteride treatment in men with BPH on erectile function and to compare these adverse effects in men treated with the α1-adrenergic receptor blocker, tamsolusin.

METHODS

In this retrospective registry study, a cohort of 470 men aged between 47 and 68 years (mean 57.78±4.81) were treated with finasteride (5 mg/day). A second cohort of 230 men aged between 52 and 72 years (mean 62.62±4.65) were treated with tamsulosin (0.4 mg). All men were followed up for 45 months. At intervals of 3 months and at each visit, plasma testosterone (T) levels and the international index of erectile function (IIEF-EF) questionnaire scores were determined.

RESULTS

Long-term treatment with finasteride therapy is associated with worsening of erectile dysfunction (ED) as shown by the significant decrease in the IIEF-EF scores in men treated with finasteride. No worsening of ED was observed in men treated with tamsulosin. The increase in ED due to finasteride did not resolve with continued treatment with finasteride. Most importantly, long-term finasteride therapy resulted in reduction in total T levels, contributing to a state of hypogonadism. On the contrary, no changes in T levels were noted in men treated with tamsolusin.

CONCLUSION

Our findings suggest that in men with BPH, long-term finasteride therapy but not tamsulosin results in worsening of ED and reduces total T concentrations. Clinicians are urged to discuss the impact of 5α-RIs therapy on sexual function with their patients before commencing this therapy.

Effects of Subchronic Finasteride Treatment and Withdrawal on Neuroactive Steroid Levels and Their Receptors in the Male Rat Brain

The enzymatic conversion of progesterone and testosterone by the enzyme 5alpha-reductase exerts a crucial role in the control of nervous function. The effects of finasteride in the brain, an inhibitor of this enzyme used for the treatment of human benign prostatic hyperplasia and androgenic alopecia, have been poorly explored. Therefore, the effects of a subchronic treatment with finasteride at low doses (3 mg/kg/day) and the consequences of its withdrawal on neuroactive steroid levels in plasma, cerebrospinal fluid and some brain regions as well as on the expression of classical and non-classical steroid receptors have been evaluated in male rats. After subchronic treatment (i.e., for 20 days) the following effects were detected: (i) depending on the compartment considered, alteration in the levels of neuroactive steroids, not only in 5alpha-reduced metabolites but also in its precursors and in neuroactive steroids from other steroidogenic pathways and (ii) an upregulation of the androgen receptor in the cerebral cortex and beta3 subunit of the GABA-A receptor in the cerebellum. One month after the last treatment (i.e., withdrawal period), some of these effects persisted (i.e., the upregulation of the androgen receptor in the cerebral cortex, an increase of dihydroprogesterone in the cerebellum, a decrease of dihydrotestosterone in plasma). Moreover, other changes in neuroactive steroid levels, steroid receptors (i.e., an upregulation of the estrogen receptor alpha and a downregulation of the estrogen receptor beta in the cerebral cortex) and GABA-A receptor subunits (i.e., a decrease of alpha 4 and beta 3 mRNA levels in the cerebral cortex) were detected. These findings suggest that finasteride treatment may have broad consequences for brain function.

The 5α-reductase inhibitor finasteride is not associated with alterations in sleep spindles in men referred for polysomnography

OBJECTIVE

Endogenous neurosteroids that potentiate the gamma-aminobutyric acid type A (GABAA ) receptor are thought to enhance the generation of sleep spindles. This study tested the hypothesis that the 5α-reductase inhibitor finasteride, an agent associated with reductions in neurosteroids, would be associated with reduced sleep spindles in men referred for polysomnography.

METHODS

Spectral analysis and spindle waveform detection were performed on electroencephalographic (EEG) sleep data in the 11-16 Hz sigma band, as well as several subranges, from 27 men taking finasteride and 27 matched comparison patients (ages 18 to 81 years).

RESULTS

No significant differences between groups were observed for spectral power or sleep spindle morphology measures, including spindle density, amplitude, duration, and integrated spindle activity.

CONCLUSIONS

Contrary to our hypothesis, these findings demonstrate that finasteride is not associated with alterations in sleep spindle range activity or spindle morphology parameters.

Exploration of steroidogenesis-related genes in testes, ovaries, adrenals, liver and adipose tissue in pigs

To explore the metabolism of steroids in the pig species, a qualitative PCR analysis was performed for the main transcript of 27 genes involved in steroid metabolism. We compared samples of testes, adipose tissue and liver from immature and peripubertal males, adrenal cortex from peripubertal males, ovaries from cyclic females and adipose tissue from peripubertal females. Some genes were shown to have a tissue-specific expression. Two of them were expressed only in testes, ovaries and adrenals: CYP11A1 and CYP11B. The CYP21 and HSD17B3 genes, were expressed respectively only in adrenals and only in testes. Very few differences were observed between transcriptional patterns of peripubertal testes and adrenal glands as well as between male and female fat tissues. However, the expression of genes involved in the sulfonation of steroids was higher in testes than in adrenals from males. Main differences between ovaries and testes were observed for HSD17B1/2/3, AKR1C-pig6 and sulfotransferase genes (SULT2A1/SULT2B1). The present study shows that the SRD5A2 and CYP21 genes were not involved in the testicular biosynthesis of androstenone. It also shows that porcine adrenal glands produce essentially corticosteroids and that fat tissue is unable to produce de novo steroids.

Adverse effects of 5α-reductase inhibitors: What do we know, don't know, and need to know?

Steroids are important physiological orchestrators of endocrine as well as peripheral and central nervous system functions. One of the key processes for regulation of these molecules lies in their enzymatic processing by a family of 5α-reductase (5α-Rs) isozymes. By catalyzing a key rate-limiting step in steroidogenesis, this family of enzymes exerts a crucial role not only in the physiological control but also in pathological events. Indeed, both 5α-R inhibition and supplementation of 5α-reduced metabolites are currently used or have been proposed as therapeutic strategies for a wide array of pathological conditions. In particular, the potent 5α-R inhibitors finasteride and dutasteride are used in the treatments of benign prostatic hyperplasia (BPH), as well as in male pattern hair loss (MPHL) known as androgenetic alopecia (AGA). Recent preclinical and clinical findings indicate that 5α-R inhibitors evoke not only beneficial, but also adverse effects. Future studies should investigate the biochemical and physiological mechanisms that underlie the persistence of the adverse sexual side effects to determine why a subset of patients is afflicted with such persistence or irreversible adverse effects. Also a better focus of clinical research is urgently needed to better define those subjects who are likely to be adversely affected by such agents. Furthermore, research on the non-sexual adverse effects such as diabetes, psychosis, depression, and cognitive function are needed to better understand the broad spectrum of the effects these drugs may elicit during their use in treatment of AGA or BPH. In this review, we will summarize the state of art on this topic, overview the key unresolved questions that have emerged on the pharmacological targeting of these enzymes and their products, and highlight the need for further studies to ascertain the severity and duration of the adverse effects of 5α-R inhibitors, as well as their biological underpinnings.

5α-Reductase inhibitors alter steroid metabolism and may contribute to insulin resistance, diabetes, metabolic syndrome and vascular disease: a medical hypothesis

5α-reductases, a unique family of enzymes with a wide host of substrates and tissue distributions, play a key role in the metabolism of androgens, progestins, mineralocorticoids and glucocorticoids. These enzymes are the rate-limiting step in the synthesis of a host of neurosteroids, which are critical for central nervous system function. Androgens and glucocorticoids modulate mitochondrial function, carbohydrate, protein and lipid metabolism and energy balance. Thus, the inhibition of these regulatory enzymes results in an imbalance in steroid metabolism and clearance rates, which leads to altered physiological processes. In this report, we advance the hypothesis that inhibition of 5α-reductases by finasteride and dutasteride alters not only steroid metabolism but also interferes with the downstream actions and signaling of these hormones. We suggest that finasteride and dutasteride inhibit 5α-reductase activities and reduce the clearance of glucocorticoids and mineralocorticoids, potentiating insulin resistance, diabetes and vascular disease.

Genetic defects in dolichol metabolism

Congenital disorders of glycosylation (CDG) comprise a group of inborn errors of metabolism with abnormal glycosylation of proteins and lipids. Patients with defective protein N-glycosylation are identified in routine metabolic screening via analysis of serum transferrin glycosylation. Defects in the assembly of the dolichol linked Glc(3)Man(9)GlcNAc(2) glycan and its transfer to proteins lead to the (partial) absence of complete glycans on proteins. These defects are called CDG-I and are located in the endoplasmic reticulum (ER) or cytoplasm. Defects in the subsequent processing of protein bound glycans result in the presence of truncated glycans on proteins. These defects are called CDG-II and the enzymes involved are located mainly in the Golgi apparatus. In recent years, human defects have been identified in dolichol biosynthesis genes within the group of CDG-I patients. This has increased interest in dolichol metabolism, has resulted in specific recognizable clinical symptoms in CDG-I and has offered new mechanistic insights in dolichol biosynthesis. We here review its biosynthetic pathways, the clinical and biochemical phenotypes in dolichol-related CDG defects, up to the formation of dolichyl-P-mannose (Dol-P-Man), and discuss existing evidence of regulatory networks in dolichol metabolism to provide an outlook on therapeutic strategies.

Differential expression of 5-alpha reductase isozymes in the prostate and its clinical implications

The development of human benign or malignant prostatic diseases is closely associated with androgens, primarily testosterone (T) and dihydrotestosterone (DHT). T is converted to DHT by 5-alpha reductase (5-AR) isozymes. Differential expression of 5-AR isozymes is observed in both human benign and malignant prostatic tissues. 5-AR inhibitors (5-ARI) are commonly used for the treatment of benign prostatic hyperplasia (BPH) and were once promoted as chemopreventive agents for prostate cancer (PCa). This review discusses the role of the differential expression of 5-AR in the normal development of the human prostate and in the pathogenesis and progression of BPH and PCa.

Evaluation of Resettin® on serum hormone levels in sedentary males

Background

Comparisons of hormones such as dihydrotestosterone (DHT), estradiol (E2), and testosterone indicate their impact on metabolism and body composition. While less is known regarding DHT and E2, testosterone is an androgenic metabolic hormone capable of positively regulating a variety of anabolic and androgenic processes in the body. Accordingly, it has been postulated that the age-related reduction in serum testosterone levels leads to reductions in lean muscle mass, bone mineral density, and other physical conditions that impair physical performance and decrease quality of life. Preliminary studies suggest that key ingredients found in Resettin®/MyTosterone™, a natural supplement containing the carotenoid astaxanthin from Haematococcus pluvialis and Saw Palmetto berry lipid extract from Serenoa repens, could positively impact testosterone levels. To investigate the clinical efficacy of Resettin®, the serum profiles of testosterone, E2 and DHT in healthy sedentary males before and after Resettin® treatment were evaluated in a randomized, placebo controlled clinical trial.

Method

Twenty healthy, sedentary men between the ages of 21 and 70 were randomized into either an 800 mg/day or 1200 mg/day Resettin®/MyTosterone™ treatment group or lecithin, which was used as the placebo. After a 14-day treatment period, there was a 14-day washout period. After the wash-out period, participants were crossed over within their respective group to either Resettin®/MyTosterone™ or the lecithin placebo for 14 days.

Results

After 14 days, participants receiving 800 mg per day of Resettin® had significantly reduced baseline-subtracted serum DHT levels in comparison to the placebo control group. While after 14 days, participants receiving 1200 mg per day of Resettin® had significantly reduced baseline-subtracted serum DHT and E2 levels in comparison to the placebo control group. Moreover, participants receiving 1200 mg per day of Resettin® experienced a 38% increase in serum testosterone levels in comparison to the placebo control group, but the effect did not reach statistical significance.

Conclusion

Although additional studies will be required to evaluate how Resettin® may promote proper testosterone regulation, these findings indicate that Resettin® can favorably influence serum hormone profiles in men.

Transcriptomic profiling in Silurana tropicalis testes exposed to finasteride

Investigations of endocrine disrupting chemicals found in aquatic ecosystems with estrogenic and androgenic modes of action have increased over the past two decades due to a surge of evidence of adverse effects in wildlife. Chemicals that disrupt androgen signalling and steroidogenesis can result in an imbalanced conversion of testosterone (T) into 17β-estradiol (E2) and other androgens such as 5α-dihydrotestosterone (5α-DHT). Therefore, a better understanding of how chemicals perturb these pathways is warranted. In this study, the brain, liver, and testes of Silurana tropicalis were exposed ex vivo to the human drug finasteride, a potent steroid 5α-reductase inhibitor and a model compound to study the inhibition of the conversion of T into 5α-DHT. These experiments were conducted (1) to determine organ specific changes in sex steroid production after treatment, and (2) to elucidate the transcriptomic response to finasteride in testicular tissue. Enzyme-linked immunosorbent assays were used to measure hormone levels in media following finasteride incubation for 6 h. Finasteride significantly increased T levels in the media of liver and testis tissue, but did not induce any changes in E2 and 5α-DHT production. Gene expression analysis was performed in frog testes and data revealed that finasteride treatment significantly altered 1,434 gene probes. Gene networks associated with male reproduction such as meiosis, hormone biosynthesis, sperm entry, gonadotropin releasing hormone were affected by finasteride exposure as well as other pathways such as oxysterol synthesis, apoptosis, and epigenetic regulation. For example, this study suggests that the mode of action by which finasteride induces cellular damage in testicular tissue as reported by others, is via oxidative stress in testes. This data also suggests that 5-reductase inhibition disrupts the expression of genes related to reproduction. It is proposed that androgen-disrupting chemicals may mediate their action via 5-reductases and that the effects of environmental pollutants are not limited to the androgen receptor signalling.

Immunohistochemical evaluation of androgen receptor and nerve structure density in human prepuce from patients with persistent sexual side effects after finasteride use for androgenetic alopecia

Finasteride is an inhibitor of 5-α-reductase used against male androgenetic alopecia (AGA). Reported side effects of finasteride comprise sexual dysfunction including erectile dysfunction, male infertility, and loss of libido. Recently these effects were described as persistent in some subjects. Molecular events inducing persistent adverse sexual symptoms are unexplored. This study was designed as a retrospective case-control study to assess if androgen receptor (AR) and nerve density in foreskin prepuce specimens were associated with persistent sexual side effects including loss of sensitivity in the genital area due to former finasteride use against AGA. Cases were 8 males (aged 29–43 years) reporting sexual side effects including loss of penis sensitivity over 6 months after discontinuation of finasteride who were interviewed and clinically visited. After informed consent they were invited to undergo a small excision of skin from prepuce. Controls were 11 otherwise healthy matched men (aged 23–49 years) who undergone circumcision for phimosis, and who never took finasteride or analogues. Differences in AR expression and nerve density in different portions of dermal prepuce were evaluated in the 2 groups. Density of nuclear AR in stromal and epithelial cells was higher in cases (mean 40.0%, and 80.6% of positive cells, respectively) than controls (mean 23.4%, and 65.0% of positive cells, respectively), P = 0.023 and P = 0.043, respectively. Conversely, percentage of vessel smooth muscle cells positive for AR and density of nerves were similar in the 2 groups. The ratio of AR positive stromal cells % to serum testosterone concentrations was 2-fold higher in cases than in controls (P = 0.001). Our findings revealed that modulation of local AR levels might be implicated in long-term side effects of finasteride use. This provides the first evidence of a molecular objective difference between patients with long-term adverse sexual effects after finasteride use versus drug untreated healthy controls in certain tissues.

The dark side of 5α-reductase inhibitors' therapy: sexual dysfunction, high Gleason grade prostate cancer and depression

With aging, abnormal benign growth of the prostate results in benign prostate hyperplasia (BPH) with concomitant lower urinary tract symptoms (LUTS). Because the prostate is an androgen target tissue, and transforms testosterone into 5α-dihydrotestosterone (5α-DHT), a potent androgen, via 5α-reductase (5α-R) activity, inhibiting this key metabolic reaction was identified as a target for drug development to treat symptoms of BPH. Two drugs, namely finasteride and dutasteride were developed as specific 5α-reductase inhibitors (5α-RIs) and were approved by the U.S. Food and Drug Administration for the treatment of BPH symptoms. These agents have proven useful in the reducing urinary retention and minimizing surgical intervention in patients with BPH symptoms and considerable literature exists describing the benefits of these agents. In this review we highlight the adverse side effects of 5α-RIs on sexual function, high grade prostate cancer incidence, central nervous system function and on depression. 5α-Rs isoforms (types 1-3) are widely distributed in many tissues including the central nervous system and inhibition of these enzymes results in blockade of synthesis of several key hormones and neuro-active steroids leading to a host of adverse effects, including loss of or reduced libido, erectile dysfunction, orgasmic dysfunction, increased high Gleason grade prostate cancer, observed heart failure and cardiovascular events in clinical trials, and depression. Considerable evidence exists from preclinical and clinical studies, which point to significant and serious adverse effects of 5α-RIs, finasteride and dutasteride, on sexual health, vascular health, psychological health and the overall quality of life. Physicians need to be aware of such potential adverse effects and communicate such information to their patients prior to commencing 5α-RIs therapy.

Pathways and genes involved in steroid hormone metabolism in male pigs: a review and update

This paper reviews state-of-the-art knowledge on steroid biosynthesis pathways in the pig and provides an updated characterization of the porcine genes involved in these pathways with particular focus on androgens, estrogens, and 16-androstenes. At least 21 different enzymes appear to be involved in these pathways in porcine tissues together with at least five cofactors. Until now, data on several porcine genes were scarce or confusing. We characterized the complete genomic and transcript sequences of the single porcine CYP11B gene. We analyzed the porcine AKR1 gene cluster and identified four AKR1C, one AKR1C like genes and one AKR1E2 gene. We provide evidence that porcine AKR1C genes are not orthologous to human AKR1C. A new nomenclature is thus needed for this gene family in the pig. Thirty-two genes are now described: transcript (30+2 characterized in this study) and genomic (complete: 18+1 and partial: 12+1) sequences are identified. However, despite increasing knowledge on steroid metabolism in the pig, there is still no explanation of why porcine testes can produce androstenone and epiandrosterone, but not dihydrotestosterone (DHT), which is also a reduced steroid.

Role of aldo-keto reductase family 1 (AKR1) enzymes in human steroid metabolism

Human aldo-keto reductases AKR1C1-AKR1C4 and AKR1D1 play essential roles in the metabolism of all steroid hormones, the biosynthesis of neurosteroids and bile acids, the metabolism of conjugated steroids, and synthetic therapeutic steroids. These enzymes catalyze NADPH dependent reductions at the C3, C5, C17 and C20 positions on the steroid nucleus and side-chain. AKR1C1-AKR1C4 act as 3-keto, 17-keto and 20-ketosteroid reductases to varying extents, while AKR1D1 acts as the sole Δ(4)-3-ketosteroid-5β-reductase (steroid 5β-reductase) in humans. AKR1 enzymes control the concentrations of active ligands for nuclear receptors and control their ligand occupancy and trans-activation, they also regulate the amount of neurosteroids that can modulate the activity of GABAA and NMDA receptors. As such they are involved in the pre-receptor regulation of nuclear and membrane bound receptors. Altered expression of individual AKR1C genes is related to development of prostate, breast, and endometrial cancer. Mutations in AKR1C1 and AKR1C4 are responsible for sexual development dysgenesis and mutations in AKR1D1 are causative in bile-acid deficiency.

Neuroactive steroid levels are modified in cerebrospinal fluid and plasma of post-finasteride patients showing persistent sexual side effects and anxious/depressive symptomatology

INTRODUCTION

Observations performed in a subset of subjects treated with finasteride (an inhibitor of the enzyme 5α-reductase) for male pattern hair loss seem to indicate that sexual dysfunction as well as anxious/depressive symptomatology may occur at the end of the treatment and continue after discontinuation.

AIM

A possible hypothesis to explain depression symptoms after finasteride treatment might be impairment in the levels of neuroactive steroids. Therefore, neuroactive steroid levels were evaluated in paired plasma and cerebrospinal fluid samples obtained from male patients who received finasteride for the treatment of androgenic alopecia and who, after drug discontinuation, still show long-term sexual side effects as well as anxious/depressive symptomatology.

METHODS

The levels of neuroactive steroids were evaluated by liquid chromatography-tandem mass spectrometry in three postfinasteride patients and compared to those of five healthy controls.

MAIN OUTCOME MEASURES

Neuroactive steroid levels in plasma and cerebrospinal fluid of postfinasteride patients and healthy controls.

RESULTS

At the examination, the three postfinasteride patients reported muscular stiffness, cramps, tremors, and chronic fatigue in the absence of clinical evidence of any muscular disorder or strength reduction. Severity and frequency of the anxious/depressive symptoms were quite variable; overall, all the subjects had a fairly complex and constant neuropsychiatric pattern. Assessment of neuroactive steroid levels in patients showed some interindividual differences. However, the most important finding was the comparison of their neuroactive steroid levels with those of healthy controls. Indeed, decreased levels of tetrahydroprogesterone, isopregnanolone and dihydrotestosterone and increased levels of testosterone and 17β-estradiol were reported in cerebrospinal fluid of postfinasteride patients. Moreover, decreased levels of dihydroprogesterone and increased levels of 5α-androstane-3α,17β-diol and 17β-estradiol were observed in plasma.

CONCLUSION

The present observations confirm that an impairment of neuroactive steroid levels, associated with depression symptoms, is still present in androgenic alopecia patients treated with finasteride despite the discontinuation of the treatment.

The efficacy and safety of 5α-reductase inhibitors in androgenetic alopecia: a network meta-analysis and benefit-risk assessment of finasteride and dutasteride

INTRODUCTION

In the light of post-marketing reports of persistent sexual dysfunction with the use of finasteride, analysis of the extent of risk associated with 5α-reductase inhibitor treatment for androgenetic alopecia (AGA) is warranted. This study sought to evaluate the efficacy of 5α-reductase inhibitors using the outcomes hair count, global photographic assessment and patient self-assessment and evaluate the benefits of treatment versus the risk of global sexual dysfunction.

METHODS

A systematic review identified all relevant randomized controlled trials of finasteride 1 mg, 5 mg and dutasteride 0.5 mg. The efficacy outcome hair count was analyzed using pair-wise meta-analysis, while the efficacy outcomes global photographic assessment and patient self-assessment as well as the safety outcome global sexual dysfunction were analyzed through network meta-analyses. A benefit-risk assessment was also performed.

RESULTS

The active interventions were not significantly different than each other in efficacy and were not significantly different from placebo in eliciting sexual dysfunction. Benefit-risk analysis resulted in an arbitrary ranking due to the lack of statistically significant difference between active treatments.

DISCUSSION

Analysis results reiterate the efficacy and safety of 5α-reductase inhibitors for the treatment of AGA and may support the approval of dutasteride 0.5 mg as an additional treatment option, following further study.