Clinical application of 5alpha-reductase inhibitors

The latest in clinical trial results of 5-alpha reductase inhibitors in combination regimens for benign prostatic hyperplasia

INTRODUCTION

BPH/male LUTS is a prevalent condition in the aging male population with multifactorial pathophysiology. Pharmacotherapy remains the cornerstone of treatment in patients who fail conservative treatment. 5-α-Reductase inhibitors (5-ARIs) are the only class of medication shown to reduce the risk of acute retention and BPH-related surgery and, thus, are commonly used along with other "short acting" medications in combination treatments.

AREAS COVERED

Combination treatments with α-blockers and 5-ARIs have been investigated extensively in high quality trials that prove the long-term efficacy of such treatments with acceptable rates of side effects. Combination treatments involving 5-ARIs and other classes of medications (anticholinergics, b3 agonists, PDEI) have been shown to be beneficial in the short term and but studies with longer follow-up periods are required to fully establish their role.

EXPERT OPINION

A-blocker/5-ARI combination treatment is a reasonable approach for patients with male LUTS/BPH who are at increased risk of disease progression or have incomplete response to monotherapies. Other combination treatments with 5-ARIs and PDEI or anticholinergics/β-3 agonists can be tried based on predominant symptoms or side effect profile, but patients should be informed about the lack of long-term data.

Approach1es for evolutionary, biochemical, and structural analysis of bacterial steroid 5α-reductases

Steroid 5α-reductases (SRD5As), also known as 3-oxo-5α-steroid 4-dehydrogenases, are essential membrane-bound enzymes involved in steroid metabolism. Belonging to the NADPH-dependent oxidoreductase family, 5α-reductases catalyze steroids with 3-oxo-Δ4 structure, such as testosterone or progesterone, to produce their corresponding 3-oxo-5α steroids, which are necessary for a variety of physiological and pathological activities. Despite their significance, SRD5A structures are still in short supply to date. Here we describe a protocol for expression, purification, crystallization, structural determination, and functional analysis of PbSRD5A, the 5α-reductase from Proteobacteria bacterium sharing high sequence identity with human SRD5A1 and SRD5A2 isozymes, which we have recently structurally characterized using a lipidic cubic phase approach. Application of similar methods to other 5α-reductase isozymes will lead to breakthroughs in the understanding of the structure, function, and mechanism of oxidoreductases implicated in steroid metabolism.

Exploring the Role of Testosterone Replacement Therapy in Benign Prostatic Hyperplasia and Prostate Cancer: A Review of Safety

Increased risk of prostate diseases triggered by testosterone replacement therapy (TRT) remains a worldwide concern. That said, we reviewed the safety of TRT in the spheres of benign prostatic hyperplasia (BPH) and prostate cancer (PCa), exploring clinical findings in this regard. Compelling evidence based on meta-analyses of randomized and observational studies indicates safety for TRT in patients suffering from prostate disorders such as BPH and PCa, at the same time improving lower tract urinary symptoms. Thus, the harmful relationship geared toward androgens and BPH seems to be overestimated as TRT has sufficient safety and, if properly prescribed, may counteract several metabolic problems. Even after PCa treatment, the benefits of TRT could outweigh the risk of recurrence, but further long-term randomized clinical trials are needed to elucidate unresolved questions.

Allopregnanolone: The missing link to explain the effects of stress on tic exacerbation?

The neurosteroid allopregnanolone (3α-hydroxy-5α-pregnan-20-one; AP) elicits pleiotropic effects in the central nervous system, ranging from neuroprotective and anti-inflammatory functions to the regulation of mood and emotional responses. Several lines of research show that the brain rapidly produces AP in response to acute stress to reduce the allostatic load and enhance coping. These effects not only are likely mediated by GABA_A receptor activation but also result from the contributions of other mechanisms, such as the stimulation of membrane progesterone receptors. In keeping with this evidence, AP has been shown to exert rapid, potent antidepressant properties and has been recently approved for the therapy of moderate-to-severe postpartum depression. In addition to depression, emerging evidence points to the potential of AP as a therapy for other neuropsychiatric disorders, including anxiety, seizures, post-traumatic stress disorder and cognitive problems. Although this evidence has spurred interest in further therapeutic applications of AP, some investigations suggest that this neurosteroid may also be associated with adverse events in specific disorders. For example, our group has recently documented that AP increases tic-like manifestations in several animal models of tic disorders; furthermore, our results indicate that inhibiting AP synthesis and signalling reduces the exacerbation of tic severity associated with acute stress. Although the specific mechanisms of these effects remain partially elusive, our findings point to the possibility that the GABAergic activation by AP may also lead to disinhibitory effects, which could interfere with the ability of patients to suppress their tics. Future studies will be necessary to verify whether these mechanisms may apply to other externalising manifestations, such as impulse-control problems and manic symptoms.

Crystal structure of steroid reductase SRD5A reveals conserved steroid reduction mechanism

Steroid hormones are essential in stress response, immune system regulation, and reproduction in mammals. Steroids with 3-oxo-Δ⁴ structure, such as testosterone or progesterone, are catalyzed by steroid 5α-reductases (SRD5As) to generate their corresponding 3-oxo-5α steroids, which are essential for multiple physiological and pathological processes. SRD5A2 is already a target of clinically relevant drugs. However, the detailed mechanism of SRD5A-mediated reduction remains elusive. Here we report the crystal structure of PbSRD5A from Proteobacteria bacterium, a homolog of both SRD5A1 and SRD5A2, in complex with the cofactor NADPH at 2.0 Å resolution. PbSRD5A exists as a monomer comprised of seven transmembrane segments (TMs). The TM1-4 enclose a hydrophobic substrate binding cavity, whereas TM5-7 coordinate cofactor NADPH through extensive hydrogen bonds network. Homology-based structural models of HsSRD5A1 and -2, together with biochemical characterization, define the substrate binding pocket of SRD5As, explain the properties of disease-related mutants and provide an important framework for further understanding of the mechanism of NADPH mediated steroids 3-oxo-Δ⁴ reduction. Based on these analyses, the design of therapeutic molecules targeting SRD5As with improved specificity and therapeutic efficacy would be possible.

Efficacy and Side Effects of Drugs Commonly Used for the Treatment of Lower Urinary Tract Symptoms Associated With Benign Prostatic Hyperplasia

Benign prostatic hyperplasia (BPH) is the most common benign disease of the prostate gland and is caused by benign hyperplasia of the smooth muscle cells and stromal cells in this important gland. BPH is also the most common disease underlying lower urinary tract symptoms (LUTS). The incidence of BPH increases with age and affects more than half of all men 50 years or older. BPH mainly exerts effects on urinary function and can seriously reduce a patient's quality of life. At present, treatment for BPH aims primarily to improve the quality of life and reduce the risk of BPH-related complications. Pharmacological therapy is recommended for moderate-to-severe cases of LUTS that are suggestive of BPH. A range of drugs is currently available to treat this condition, including α1-adrenoceptor antagonists, 5α-reductase inhibitors (5-ARIs), phosphodiesterase type 5 inhibitors (PDE5Is), muscarinic receptor antagonists (MRAs), β3-adrenoceptor agonists, and plant extracts. Of these, the most commonly used drugs in the clinic are α1-adrenoceptor antagonists, 5-ARIs, and combination therapy. However, these drugs exert their effects via various mechanisms and are associated with adverse reactions. The purpose of this review is to provide current comprehensive perspectives on the mechanisms of action, efficacy, and adverse reactions associated with the drugs most commonly used for the treatment of BPH.

Post-finasteride syndrome - does it really exist?

Inhibitors of 5α-steroid reductase are drugs used to treat androgen-dependent conditions including prostate diseases and androgenic alopecia. Finasteride was the first on the market and is currently the most widely used inhibitor. Dutasteride was the second inhibitor to be approved and has a similar safety profile. Common adverse events of treatment consist of sexual disorders and a negative affect balance. It was described that the prolonged use of 5α-steroid reductase inhibitors in patients with alopecia can cause persistent side effects called a post-finasteride syndrome (PFS), that is not just a simple coexistence of events, but rather a definite syndrome with an iatrogenic background. PFS occurs in susceptible individuals even after small doses of the drug and can last for a long time after the discontinuation of treatment. A deterioration in the quality of life in affected individuals does not justify use of the drug. Wider recognition of PFS symptoms, its incidence, course, prevention, and treatment possibilities will allow the indications for drug use to be reconsidered and treatment to be more personalized. Knowledge about PFS will also help to provide the best treatment for affected individuals and to properly educate patients before obtaining an informed consent for therapy with 5α-steroid reductase inhibitors.

Neuropsychological Assessment in Elderly Men with Benign Prostatic Hyperplasia Treated with Dutasteride

BACKGROUND AND OBJECTIVE

Benign prostatic hyperplasia (BPH) is a common disease found in elderly men and 5α-reductase (5α-R) inhibitors are a commonly used treatment option. 5α-reduced steroids are compounds that play a role in several functions across different organs and systems. In the adult brain, 5α-R accounts for neuroactive steroid production. Whether neuropsychological impairment could be due to dutasteride treatment, a 5α-R inhibitor affecting the production of dihydrotestosterone (DHT), is still unknown. The aim of our study was to investigate neuropsychological features in men receiving dutasteride.

METHODS

The Mini Mental State Examination (MMSE), the Clock Drawing Test (CDT), the Frontal Assessment Battery (FAB), the Hamilton Anxiety Rating Scale (HAM-A), the Beck Depression Inventory second edition (BDI-II) and the Short Form-12 (SF-12) questionnaire were administered in order to explore both cognitive impairment and psychological features.

RESULTS

In a sample of BPH patients (n = 40; mean age 71.4 ± 7.4 years), men receiving dutasteride showed no significant differences during the neuropsychological assessment in comparison with an age-matched control group, consisting of BPH men not receiving dutasteride (p < 0.05). No significant associations were recorded between treatment duration and any of the administered tests.

CONCLUSIONS

This is the first study investigating the neuropsychological features in dutasteride users. Our preliminary data are consistent with the safety of dutasteride under a mental profile.

Subcellular localization of the five members of the human steroid 5α-reductase family

In humans the steroid 5α-reductase (SRD5A) family comprises five integral membrane enzymes that carry out reduction of a double bond in lipidic substrates: Δ⁴-3-keto steroids, polyprenol and trans-enoyl CoA. The best-characterized reaction is the conversion of testosterone into the more potent dihydrotestosterone carried out by SRD5A1-2. Some controversy exists on their possible nuclear or endoplasmic reticulum localization.

We report the cloning and transient expression in HeLa cells of the five members of the human steroid 5α-reductase family as both N- and C-terminus green fluorescent protein tagged protein constructs. Following the intrinsic fluorescence of the tag, we have determined that the subcellular localization of these enzymes is in the endoplasmic reticulum, upon expression in HeLa cells. The presence of the tag at either end of the polypeptide chain can affect protein expression and, in the case of trans enoyl-CoA reductase, it induces the formation of protein aggregates.

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All members of human testosterone 5α-reductase family were expressed in HeLa cells.

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Subcellular localization of SRD5A proteins in the endoplasmic reticulum is reported.

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The effect of GFP tagging at N- or C-term on SRD5A proteins expression was assessed.

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The TECRL gene is expressed for the first time and its product localizes in the ER.

Тіе Modern treatment of androgenetic alopecia

Androgenetic alopecia (AGA) is the most common reason for hair loss. Its frequency in Caucasian population is up to 80% in men and 42% in women. Current gold standard for AGA treatment includes minoxidil and/or finasteride. Both drugs have moderate treatment efficacy and can cause significant side effects. Minoxidil is the only option for treatment of AGA in women since finasteride has no efficacy. This review considers actual concepts of molecular mechanisms of pathogenesis and current treatment options of AGA with their limitations and shortcomings. Current state and perspectives of novel approaches to AGA treatment, potentially more effective and safe than minoxidil and finasteride, are described. The review discusses growth factors and cytokines, topical 5-alpha-reductase inhibitors, androgen receptor antagonists, prostaglandin analogs and antagonists, Wnt signaling activators and platelet-rich plasma injections.

The epidemiology of acne vulgaris in late adolescence

Importance

Acne vulgaris is the most common skin condition affecting late adolescents across the globe. Although prior studies have evaluated epidemiologic patterns of acne vulgaris in various ethnicities and regions, adequate understanding of the worldwide burden of the disease associated with patients in their late adolescence (15–19-year olds) remains lacking.

Objective

To assess the global burden of the disease associated with acne vulgaris for late adolescents (15–19-year olds) and provide an overview of the epidemiology, pathophysiology, and treatment options for acne in this population.

Design

Database summary study.

Setting

Global Burden of Disease Study 2010 database.

Participants

Global Burden of Disease regions comprised countries with prevalence of acne vulgaris between the ages of 15 and 19 years.

Main outcomes and measures

Geographic region-level disability-adjusted life year rates (per 100,000 persons) associated with acne vulgaris in years 1990 through 2010. Median percentage change in disability-adjusted life year rates was estimated for each region across the specified study period.

Conclusion and relevance

Acne vulgaris-associated disease burden exhibits global distribution and has continued to grow in prevalence over time within this population. This continued growth suggests an unmet dermatologic need worldwide for this disorder and potential opportunities for improved access and delivery of dermatologic care. Our analysis of the literature reveals numerous opportunities for enhanced patient care. To that end, we highlight some of the effective and promising treatments currently available and address important factors, such as sex, nationality, genetics, pathophysiology, and diet, as they relate to acne vulgaris in late adolescence.

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.

A new simple and high-yield synthesis of 5α-dihydrotestosterone (DHT), a potent androgen receptor agonist

We have devised an efficient procedure for the synthesis of 5α-dihydrotestosterone (DHT) (1) starting from 3β-hydroxy-5α-androstan-17-one, providing the product in unprecedented 82% yield. A reported method of using toxic Jones reagent is replaced by milder oxidizing agent (NMO/TPAP) in the synthesis of a key intermediate 17β-[(tert-butyldimethylsilyl)oxy]-5α-androstan-3-one (18). This new procedure is simple, does not require special apparatus/precautions or chromatographic purification in most of the steps.

The 5 alpha-reductase isozyme family: a review of basic biology and their role in human diseases

Despite the discovery of 5 alpha-reduction as an enzymatic step in steroid metabolism in 1951, and the discovery that dihydrotestosterone is more potent than testosterone in 1968, the significance of 5 alpha-reduced steroids in human diseases was not appreciated until the discovery of 5 alpha-reductase type 2 deficiency in 1974. Affected males are born with ambiguous external genitalia, despite normal internal genitalia. The prostate is hypoplastic, nonpalpable on rectal examination and approximately 1/10th the size of age-matched normal glands. Benign prostate hyperplasia or prostate cancer does not develop in these patients. At puberty, the external genitalia virilize partially, however, secondary sexual hair remains sparse and male pattern baldness and acne develop rarely. Several compounds have been developed to inhibit the 5 alpha-reductase isozymes and they play an important role in the prevention and treatment of many common diseases. This review describes the basic biochemical properties, functions, tissue distribution, chromosomal location, and clinical significance of the 5 alpha-reductase isozyme family.

Clinical and instrumental study of the efficacy of a new sebum control cream

BACKGROUND

Some botanical compounds are considered useful to reduce sebum production. Aim To evaluate the efficacy of a sebum control cream containing polyphenol-rich extract from saw palmetto, sesame seeds, and argan oil in subjects with oily facial skin.

METHODS

The study was carried out during the winter months (January and February). A total of 20 healthy volunteers (9 male and 11 female, aged 17-50 years, 16 with oily skin and 4 with combined skin) were studied. The test product was applied twice daily to the face for a period of 4 weeks. A clinical assessment and instrumental measurements were done before and after the treatment period. Casual sebum level on the forehead and both cheeks was determined with a photometric device (Sebumeter). The quantity of sebum on the midforehead was determined using sebum collector foils (Sebufix), which were then evaluated with skin camera Visioscope and software SELS (Surface Evaluation of the Living Skin). A subjective evaluation questionnaire regarding the cosmetic characteristics, tolerance, and efficacy of the product was filled out by the volunteers at the end of study.

RESULTS

The product was very well accepted by all the volunteers. A visible sebum-regulating efficacy was reported in 95% of them. After 4 weeks of treatment, the clinical assessment scores decreased by 33%. There was a significant reduction in the casual sebum level by 20% and area covered with oily spots by 42%. The number of active sebaceous glands remained unaltered.

CONCLUSION

These results objectively and quantitatively show the efficacy of the sebum control cream tested to reduce the greasiness and improve the appearance of oily facial skin.

Doping-Control Analysis of the 5α-Reductase Inhibitor Finasteride: Determination of Its Influence on Urinary Steroid Profiles and Detection of Its Major Urinary Metabolite

5alpha-Reductase inhibitors such as finasteride are prohibited in sports according to the World Anti-Doping Agency. This class of drugs is used therapeutically to treat benign prostatic hyperplasia, as well as male baldness, by decreasing 5alpha-reductase activity. Accordingly, metabolic pathways of endogenous as well as synthetic steroids are influenced, which complicates the evaluation of steroid profiles in sports drug testing. The possibility of manipulating steroid excretion profiles and, presumably, to mask steroid abuse was investigated in 5 administration studies with use of finasteride at different doses, with and without coadministration of 19-norandrostenedione. The evaluation of urinary steroid profiles demonstrated the intense effect of finasteride on numerous crucial analytical parameters, in particular the production of 5alpha-steroids such as androsterone and 5alpha-androstane-3alpha,17beta-diol, which was significantly reduced. In addition, the excretion of the main metabolite of norandrostenedione, norandrosterone, was significantly suppressed, by up to 84%, in elimination studies. For doping-control analysis the use of 5alpha-reductase inhibitors causes considerable problems because steroid profile parameters, which are commonly considered stable, are highly affected and complicate the detection of steroid abuse. In addition, the suppression of production and renal excretion of 5alpha-steroids such as 19-norandrosterone generated from anabolic agents such as 19-norandrostenedione may lead to false-negative doping-control results, because urine specimens are reported positive only when a threshold level of 2 ng/mL is exceeded. Finally, a method for the determination of the major urinary metabolite of finasteride (carboxy-finasteride) in routine doping-control screening with use of liquid chromatography-tandem mass spectrometry is described, allowing the detection of carboxy-finasteride for up to 94 hours in urine specimens collected after an oral administration of 5 mg of finasteride.

Finasteride induced depression: a prospective study

Background

Finasteride is a competitive inhibitor of 5 alpha-reductase enzyme, and is used for treatment of benign prostatic hyperplasia and androgenetic alopecia. Animal studies have shown that finasteride might induce behavioral changes. Additionally, some cases of finasteride-induced depression have been reported in humans. The purpose of this study was to examine whether depressive symptoms or anxiety might be induced by finasteride administration.

Methods

One hundred and twenty eight men with androgenetic alopecia, who were prescribed finasteride (1 mg/day) were enrolled in this study. Information on depressed mood and anxiety was obtained by Beck Depression Inventory (BDI), and Hospital Anxiety and Depression Scale (HADS). Participants completed BDI and HADS questionnaires before beginning the treatment and also two months after it.

Results

Mean age of the subjects was 25.8(± 4.4) years. At baseline, mean BDI and HADS depression scores were 12.11(± 7.50) and 4.04(± 2.51), respectively. Finasteride treatment increased both BDI (p < 0.001) and HADS depression scores significantly (p = 0.005). HADS anxiety scores were increased, but the difference was not significant (p = 0.061).

Conclusion

This preliminary study suggests that finasteride might induce depressive symptoms; therefore this medication should be prescribed cautiously for patients with high risk of depression. It seems that further studies would be necessary to determine behavioral effects of this medication in higher doses and in more susceptible patients.

A new look at the 5alpha-reductase inhibitor finasteride

Finasteride is the first 5alpha-reductase inhibitor that received clinical approval for the treatment of human benign prostatic hyperplasia (BPH) and androgenetic alopecia (male pattern hair loss). These clinical applications are based on the ability of finasteride to inhibit the Type II isoform of the 5alpha-reductase enzyme, which is the predominant form in human prostate and hair follicles, and the concomitant reduction of testosterone to dihydrotestosterone (DHT). In addition to catalyzing the rate-limiting step in the reduction of testosterone, both isoforms of the 5alpha-reductase enzyme are responsible for the reduction of progesterone and deoxycorticosterone to dihydroprogesterone (DHP) and dihydrodeoxycorticosterone (DHDOC), respectively. Recent preclinical data indicate that the subsequent 3alpha-reduction of DHT, DHP and DHDOC produces steroid metabolites with rapid non-genomic effects on brain function and behavior, primarily via an enhancement of gamma-aminobutyric acid (GABA)ergic inhibitory neurotransmission. Consistent with their ability to enhance the action of GABA at GABA(A) receptors, these steroid derivatives (termed neuroactive steroids) possess anticonvulsant, antidepressant and anxiolytic effects in addition to altering aspects of sexual- and alcohol-related behaviors. Thus, finasteride, which inhibits both isoforms of 5alpha-reductase in rodents, has been used as a tool to manipulate neuroactive steroid levels and determine the impact on behavior. Results of some preclinical studies and clinical observations with finasteride are described in this review article. The data suggest that endogenous neuroactive steroid levels may be inversely related to symptoms of premenstrual and postpartum dysphoric disorder, catamenial epilepsy, depression, and alcohol withdrawal.

Neurosteroids, neuroactive steroids, and symptoms of affective disorders

Neurosteroids (NS) are steroids synthesized by the brain. Neuroactive steroids (NAS) refers to steroids that, independent of their origin, are capable of modifying neural activities. NAS bind and modulate different types of membrane receptors. The gamma amino butyric acid (GABA) and sigma receptor complexes have been the most extensively studied. Oxidized ring A reduced pregnanes, tetrahydroprogesterone (THP), and tetrahydrodeoxycorticosterone (THDOC) bind to the progesterone intracellular receptor (PR), and in this way can also regulate gene expression. Animal experimentation showed that salient symptoms of depression, viz., anxiety, sleep disturbances, and memory and sexual dysfunctions, are modulated by NAS. In turn, psychotropic drugs modulate NS and NAS levels. NS levels as well as NAS plasma concentrations change in patients with depression syndromes, the levels return to normal baseline with recovery, but normalization is not necessary for successful therapy. Results from current studies on the evolution of nervous systems, including evolutionary developmental biology as well as anatomical and physiological findings, almost preclude a categorical classification of the psychiatric ailments the human brain succumbs to. The persistence in maintaining such essentialist classifications may help to explain why up to now the search for biological markers in psychiatry has been an unrewarding effort. It is proposed that it would be more fruitful to focus on relationships between NAS and symptoms of psychiatric disorders, rather than with typologically defined disorders.

Isoenzyme type 1 of 5alpha-reductase is abundantly transcribed in normal human genital skin fibroblasts and may play an important role in masculinization of 5alpha-reductase type 2 deficient males

OBJECTIVE

5alpha-reductase enzymes reduce testosterone (T) to the most potent androgen dihydrotestosterone (DHT). Two isoenzymes are known to day. While the type 2-enzyme (5RII) is predominantly expressed in male genital tissues and mutations are known to cause a severe virilization disorder in genetic males, the role of the type 1-enzyme (5RI) in normal male androgen physiology is unclear. We investigated whether 5RI is transcribed in normal male genital skin fibroblasts (GSFs) and if the transcription is regulated by age or by androgens themselves.

METHODS

GSF from 14 normally virilized males of different ages, ranging from 8 months to 72 years, obtained at circumcision were cultured. Total RNA was isolated after incubation for 48 h with 100 nM T or without androgens. Each sample was amplified in triplicate by real-time PCR with porphobilinogen desaminase as a housekeeping gene used for semiquantification. Selected cultures were analyzed after incubation with 10 and 100 nM T and 1 and 100 nM DHT for 24, 48 and 120 h.

RESULTS

5RI was transcribed in all investigated samples with a 4.5-fold variability in the mRNA concentration of different individuals. However, neither age-related regulation nor significant influence of T or DHT on the transcription rate was discovered.

CONCLUSION

Since 5RI is abundantly transcribed in GSFs, we hypothesize that this isoenzyme may play important roles in the androgen physiology of normally virilized males and may contribute to masculinization in 5RII-deficient males at the time of puberty.

Comparative pharmacophore development for inhibitors of human and rat 5-alpha-reductase

There are a number of diseases where the 5-alpha-reductase (5AR) enzyme is of therapeutic interest as a drug target. Currently the crystal structure for 5-alpha-reductase is unavailable, thus ligand-based pharmacophore techniques are beneficial in the drug development process. We have developed pharmacophores to aid inhibitor design for both human types I (preliminary) and II 5-alpha-reductase isozymes and also the rat type II isozyme. To our knowledge, these are the first published pharmacophores for inhibitors of the human type I and rat type II enzymes. A comparison between isozymes and the previously published human type II isozyme pharmacophore is also presented.

Therapie der Akne mit Antiandrogenen - Eine evidenzbasierte Ubersicht. Treatment of acne with antiandrogens - an evidence-based review

BACKGROUND

Increased sebaceous gland activity with seborrhea is one of the major pathogenetic factors in acne. Antiandrogen treatment targets the androgen-metabolizing follicular keratinocytes and the sebaceous gland leading to sebostasis, with a reduction of the sebum secretion rate of 12.5-65%. Antiandrogens can be classified based on their mechanism of action as androgen receptor blockers, inhibitors of circulating androgens by affecting ovarian function (oral contraceptives), inhibitors of circulating androgens by affecting the pituitary (gonadotropin-releasing hormone agonists and dopamine agonists in hyperprolactinemia), inhibitors of adrenal function, and inhibitors of peripheral androgen metabolism (5alpha-reductase inhibitors, inhibitors of other enzymes).

METHODS

All original and review publications on antiandrogen treatment of acne as monotherapy or in combination included in the MedLine system were extracted by using the terms "acne", "seborrhea", "polycystic ovary syndrome", "hyperandrog", and "treatment" and classified according to their level of evidence.

RESULTS

The combinations of cyproterone acetate (2 mg)/ethinyl estradiol (35 microg), drospirenone (3 mg)/ethinyl estradiol (30 microg), and desogestrel (25 microg)/ ethinyl estradiol (40 microg) for 1 week followed by desogestrel (125 microg)/ethinyl estradiol (30 microg) for 2 weeks showed the strongest anti-acne activity. Gestagens or estrogens as monotherapy, spironolactone, flutamide, gonadotropin-releasing hormone agonists, and inhibitors of peripheral androgen metabolism cannot be endorsed based on current knowledge. Low dose prednisolone is only effective in late-onset congenital adrenal hyperplasia and dopamine agonists only in hyperprolactinemia. Treatment with antiandrogens should only be considered if none of the contraindications exist.

CONCLUSION

Antiandrogen treatment should be limited to female patients with additional signs of peripheral hyperandrogenism or hyperandrogenemia. In addition, women with late-onset or recalcitrant acne who also desire contraception can be treated with antiandrogens as can those being treated with systemic isotretinoin. Antiandrogen treatment is not appropriate primary monotherapy for noninflammatory and mild inflammatory acne.

New evidence of similarity between human and plant steroid metabolism: 5alpha-reductase activity in Solanum malacoxylon

The physiological role of steroid hormones in humans is well known, and the metabolic pathway and mechanisms of action are almost completely elucidated. The role of plant steroid hormones, brassinosteroids, is less known, but an increasing amount of data on brassinosteroid biosynthesis is showing unexpected similarities between human and plant steroid metabolic pathways. Here we focus our attention on the enzyme 5alpha-reductase (5alphaR) for which a plant ortholog of the mammalian system, DET2, was recently described in Arabidopsis thaliana. We demonstrate that campestenone, the natural substrate of DET2, is reduced to 5alpha-campestanone by both human 5alphaR isozymes but with different affinities. Solanum malacoxylon, which is a calcinogenic plant very active in the biosynthesis of vitamin D-like molecules and sterols, was used to study 5alphaR activity. Leaves and calli were chosen as examples of differentiated and undifferentiated tissues, respectively. Two separate 5alphaR activities were found in calli and leaves of Solanum using campestenone as substrate. The use of progesterone allowed the detection of both activities in calli. Support for the existence of two 5alphaR isozymes in S. malacoxylon was provided by the differential actions of inhibitors of the human 5alphaR in calli and leaves. The evidence for the presence of two isozymes in different plant tissues extends the analogies between plant and mammalian steroid metabolic pathways.