Androgen-binding Activity Research Articles

Endocrine disruption: the noise in available data adversely impacts the models’ performance

ABSTRACT This paper is devoted to the analysis of available experimental data and preparation of predictive models for binding affinity of molecules with respect to two nuclear receptors involved in endocrine disruption (ED): the oestrogen (ER) and the androgen (AR) receptors. The ED-relevant data were retrieved from multiple sources, including the CERAPP, CoMPARA, and the Tox21 projects as well as ChEMBL and PubChem databases. Data analysis performed with the help of generative topographic mapping revealed the problem of low agreement between experimental values from different sources. Collected data were used to train both classification models for ER and AR binding activities and regression models for relative binding affinity (RBA) and median inhibition concentration (IC50). These models displayed relatively poor performance in classification (sensitivities ER = 0.34, AR = 0.49) and in regression (determination coefficient r 2 for the RBA and IC50 models in external validation varied from 0.44 to 0.76). Our analysis demonstrates that low models’ performance resulted from misinterpreted experimental endpoints or wrongly reported values, thus confirming the observations reported in CERAPP and CoMPARA studies. Developed models and collected data sets included of 6215 (ER) and 3789 (AR) unique compounds, which are freely available.

Binary and multi-class classification for androgen receptor agonists, antagonists and binders

Androgens and androgen receptor regulate a variety of biological effects in the human body. The impaired functioning of androgen receptor may have different adverse health effects from cancer to infertility. Therefore, it is important to determine whether new chemicals have any binding activity and act as androgen agonists or antagonists before commercial use. Due to the large number of chemicals that require experimental testing, the computational methods are a viable alternative. Therefore, the aim of the present study was to develop predictive QSAR models for classifying compounds according to their activity at the androgen receptor. A large data set of chemicals from the CoMPARA project was used for this purpose and random forest classification models have been developed for androgen binding, agonistic, and antagonistic activity. In addition, a unique effort has been made for multi-class approach that discriminates between inactive compounds, agonists and antagonists simultaneously. For the evaluation set, the classification models predicted agonists with 80% of accuracy and for the antagonists’ and binders’ the respective metrics were 72% and 78%. Combining agonists, antagonists and inactive compounds into a multi-class approach added complexity to the modelling task and resulted to 64% prediction accuracy for the evaluation set. Considering the size of the training data sets and their imbalance, the achieved evaluation accuracy is very good. The final classification models are available for exploring and predicting at QsarDB repository (https://doi.org/10.15152/QDB.236).

Androgen receptor: role in the female lower vertebrate reproduction

Recent research provides a more detailed understanding of the androgen and androgen receptor system role in mammalian female physiology indicating the essential value in reproduction. Here, we summarize androgen and androgen receptor biochemical and immunohistochemical brain studies of different vertebrate classes and, in detail, our investigations conducted on the female of the seasonal breeders, the amphibian anura Rana esculenta and the reptile, Podarcis sicula. The results have been achieved seasonally through plasma steroid radioimmunoassay and brain androgen binding activity by biochemical identification as well by androgen receptor immunolocalization and neuroanatomical distribution. Taken together, the seasonal fluctuations and the signal intensity in the different target cells of established encephalic district extend knowledge of the central action of the androgen in the lower vertebrate providing considerable understanding of the physiology role of the androgen/androgen receptor system in the female lower vertebrate reproduction.

Single exposure to low dose of lindane causes transient decrease in testicular steroidogenesis in adult male Wistar rats

Substantial evidence has piled up portending the adverse effects of environmental toxicants on male reproduction. Lindane, an organochlorine pesticide, has been reported to perturb testicular functions and hence fertility. To get more insight into the mechanism(s) involved in gonadal effect(s) of lindane, we sought to investigate whether treatment with lindane at a low dose would alter the levels of steroidogenic acute regulatory protein (StAR), androgen binding protein (ABP) and activities of steroidogenic enzymes (3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase) in adult rat. Furthermore, the levels of H 2O 2 were monitored to delineate the possible role of H 2O 2 in mediating the testicular effects of lindane. Animals used for experimentation were divided into six groups and four animals were maintained in each group. Animals were administered with a single dose of lindane (5 mg/kg body weight) and terminated at specific post-treatment intervals (0 h, 3 h, 6 h, 12 h, 24 h and 72 h) to analyze the early testicular response. Administration of lindane resulted in a sequential reduction in the levels of StAR and the activities of steroidogenic enzymes with a parallel increase in the levels of H 2O 2. These changes elicited by lindane were significant at 12 h and 24 h post-treatment. In case of ABP, a significant decline in the level was found at 12 h after treatment. These findings demonstrate transient inhibitory effects of lindane on testicular steroidogenesis and the possible role of H 2O 2 in mediating these effects.

Effects of vitamin C on androgen receptor mediated actions in human prostate adenocarcinoma cell line LAPC-4

Objectives To examine the effects of vitamin C (VC) on androgen receptor (AR)-mediated functions in a human prostate cancer cell line, Los Angeles prostate cancer (LAPC-4). VC is an essential dietary substance in the maintenance and preservation of vital functions in humans. However, the role of VC in prostate cancer remains to be elucidated. Methods Cell proliferation and the expression of two well-known androgen regulated proteins, prostate-specific antigen and human glandular kallikrein-2, were studied in the presence of VC. Results In the presence of androgen and VC, both cell growth and the expression of prostate-specific antigen and human glandular kallikrein-2 proteins were decreased. Moreover, AR-mediated transcription activity of the prostate-specific antigen gene was suppressed with VC, similar to the phenomenon observed when cells were treated with hydrogen peroxide. These effects were reversed with catalase. However, additional studies did not reveal changes in the expression level of AR protein or its androgen-binding activity with the addition of VC. Conclusions The results of our study suggest that the pro-oxidant property of VC might be one of the mechanisms by which it modulates AR-mediated function in LAPC-4 cells.

Differential regulation of gonadotropin-releasing hormone secretion and gene expression by androgen: membrane versus nuclear receptor activation.

Steroid hormones induce rapid membrane receptor-mediated effects that appear to be separate from long-term genomic events. The membrane receptor-mediated effects of androgens on GT1-7 GnRH-secreting neurons were examined. We observed androgen binding activity with a cell-impermeable BSA-conjugated testosterone [testosterone 3-(O-carboxymethyl)oxime (T-3-BSA)] and were able to detect a 110-kDa protein recognized by the androgen receptor (AR) monoclonal MA1-150 antibody in the plasma membrane fraction of the GT1-7 cells by Western analysis. Further, a transfected green fluorescent protein-tagged AR translocates and colocalizes to the plasma membrane of the GT1-7 neuron. Treatment with 10 nM 5alpha-dihydrotestosterone (DHT) inhibits forskolin-stimulated accumulation of cAMP, through a pertussis toxin-sensitive G protein, but has no effect on basal cAMP levels. The inhibition of forskolin-stimulated cAMP accumulation by DHT was blocked by hydroxyflutamide, a specific inhibitor of the nuclear AR. DHT, testosterone (T), and T-3-BSA, all caused significant elevations in intracellular calcium concentrations ([Ca(2+)](i)). T-3-BSA stimulates GnRH secretion 2-fold in the GT1-7 neuron, as did DHT or T. Interestingly GnRH mRNA levels were down-regulated by DHT and T as has been reported, but not by treatment with T-3-BSA or testosterone 17beta-hemisuccinate BSA. These studies indicate that androgen can differentially regulate GnRH secretion and gene expression through specific membrane-mediated or nuclear mechanisms.

A Low-Molecular-Weight Cytosolic Inhibitor of the Specific Testosterone Binding in Bovine Seminal Vesicles

Bovine seminal vesicle cytosol contains a low-molecular-weight and thermostable substance which specifically inhibits the binding of testosterone to its cognate receptor. The mass and the ether phospholipid structure of the inhibitor were elucidated by mass spectrometry. Saturation and binding experiments indicate that the inhibitor acts in a dose-dependent and competitive manner, altering the apparent dissociation constant (KD) while maintaining the number of androgen-binding sites (Bmax). Its possible role in the regulation of androgen binding activity is discussed.

Reproductive malformation of the male offspring following maternal exposure to estrogenic chemicals.

Recently, significant concerns have been placed on the widespread use of chemicals with persistent estrogenic activity for their long-term effects on human health. In this communication, we investigated whether fetal exposure to some of these chemicals at doses consumed by people, has any long-term effect on the reproductive functions of the male offspring. Thus, time-pregnant CD-1 mice were fed diethylstilbestrol (DES), bisphenol A (BPA), and aroclor (aroclor 1016) at an average concentration of 100 ng/kg/day, 50 microg/kg/day, and 50 microg/kg/day, respectively, during Days 16-18 of gestation. A high dose of DES (200 microg/kg/day) was also tested to compare the results of the current study with those of others using the high dose only. The offspring were examined at Day 3, Day 21, and Day 60 following birth. We demonstrated that BPA, aroclor, and the lower dose of DES enhanced anogenital distance, increased prostate size, and decreased epididymal weight. No effect was found on the testicular weight or size. The chemicals also permanently increased androgen receptor (AR) binding activity of the prostate at this dosage. This is the first demonstration that environmental chemicals program AR function permanently at the dosage consumed by the general population. The higher dosage of DES, on the other hand, produced an opposite effect, decreasing prostate weight, prostate AR binding, and anogenital distance, thus confirming the previous reports. To investigate whether the above mentioned effects of the chemicals represent direct or indirect effects, we also tested the effect of the chemicals on prostate development in vitro. Thus fetal urogenital sinus (UGS), isolated at the 17th day of gestation was cultured with the chemicals in the presence and absence of testosterone (10 ng/ml) for 6 days, and prostate growth was monitored by determining the size and branching of the specimen following histology. Results showed that these chemicals induced prostate growth in the presence and absence of testosterone. They also increased androgen-binding activity. Thus, the results of the in vivo studies were reproduced in the in vitro experiments, suggesting a direct effect of these chemicals on the development of fetal reproductive organs. This is the first demonstration that estrogenic chemicals induce reproductive malformation by direct interference with the fetal reproductive organs and not by interfering with the maternal or fetal endocrine system. The chemicals are able to induce malformation even in the absence of fetal testosterone; however, they are more effective in the presence of testosterone.

Trafficking of androgen receptor mutants fused to green fluorescent protein: a new investigation of partial androgen insensitivity syndrome.

The naturally occurring mutations of the androgen receptor (AR), detected in patients with androgen insensitivity syndrome (AIS), are currently analyzed by in vitro assays. Unfortunately, these assays do not always permit the demonstration of a direct relationship between the in vitro activity of the receptor and the severity of the phenotype (in particular, for mutations detected in patients with partial AIS). We recently studied the trafficking of wild-type AR, fused to the green fluorescent protein (GFP) in living cells. In the present study, we applied this method for the analysis of AR mutants to find out whether it could be a complementary method of investigation of AIS. After construction of the GFP-AR mutant fusion proteins, the androgen-binding characteristics, nuclear transfer capacities, and transcriptional activities were evaluated. The nuclear transfer was quantified in the presence of various concentrations of dihydrotestosterone (DHT). We studied two mutants associated with partial AIS: G743V and R840C. The androgen-binding characteristics of both mutants were affected, in comparison with normal AR. Although the affinities were similar, the dissociation rate of GFP-AR-G743V was twice that of GFP-AR-R840C. In transcriptional assay, both mutants were active only at high concentrations of androgen. The nuclear trafficking of the mutants was evaluated by two parameters: 1) the rate of nuclear transfer; and 2) the maximal amount of receptors imported into the nucleus. At 10(-6) mol/L DHT, the GFP-AR mutants entered into the nucleus in a fashion similar to that of GFP-AR-wt. At 10(-7) mol/L DHT, the rate and maximal degree of nuclear import were both reduced, even more, for GFP-AR-G743V. The difference between mutants was more pronounced at 10(-9) mol/L DHT, because GFP-AR-G743V entered into the nucleus with even slower kinetics. Though the androgen-binding affinity and transcriptional activity assays did not reveal major differences between mutants, the dissociation rate and the trafficking capacity measurements permitted the activity of the mutants to be differentiated. We observed that the nuclear transfer capacities of these mutants are in correlation with the severity of the phenotype. The GFP-AR model provides an opportunity both to observe the dynamics of the hormone/receptor complex in living cells and to study the impact of the ligand-binding domain mutation, as opposed to certain in vitro techniques. Because the nuclear import capacity correlates well with the degree of androgen insensitivity, the GFP-AR is a useful complementary tool to understanding the phenotype/genotype relationship of AR function in patients with AIS.

Wide variation in androgen receptor dysfunction in complete androgen insensitivity syndrome.

Androgen insensitivity syndrome (AIS) is a disorder of male sexual differentiation caused by mutations in the androgen receptor (AR) gene. The partial form (PAIS), associated with varying degrees of receptor dysfunction, presents with a range of undervirilization phenotypes. The complete form (CAIS) is characterized by normal female external appearance at birth. In these cases the receptor is often absent or inactive. However, cases have been described where the mutant receptor concerned has considerable residual activity in in vitro assays. Here we describe the effects of five mutations, Gly750Asp, Leu762Phe, Ala765Thr, Asp864Asn and Leu907Phe, identified in complete androgen insensitivity patients. In vitro assays of mutant androgen receptors expressed in a mammalian cell line showed that the Gly750Asp, Leu762Phe and Ala765Thr mutations cause almost complete loss of androgen-binding activity, suggesting that these residues are critical for ligand binding. However, receptors with Asp864Asn and Leu907Phe, although defective, were capable of considerable binding and transactivation activity. Given that some mutations identified in PAIS patients have a more severe effect on androgen receptor function than two CAIS mutations described here, these results provide further evidence that other factors, including genetic background, can have a significant impact on the phenotype associated with a particular AR mutation.

Activation of androgen receptor in epidermal growth factor modulation of fetal mouse sexual differentiation

Previous studies from this laboratory indicated a role for epidermal growth factor (EGF) in androgen-dependent male sexual differentiation. The mechanism by which EGF modulates male sexual differentiation has not been determined and investigation has been made to assess the role for androgen receptor (AR) in mediating the EGF-induced effect. We report that EGF, like androgen, stabilized the Wolffian duct in the 13-day female specimen, grown in organ culture. Anti-AR, flutamide and cyproterone acetate blocked the Wolffian duct-stabilizing effect of EGF. EGF also induced cell proliferation of the fetal reproductive tract in a dose-dependent manner and a combination of physiological dosages of EGF and androgen-induced cell proliferation synergistically, suggesting an interactive effect of these two drugs. Cyproterone acetate blocked both EGF-induced normal cell proliferation and the synergistic cell proliferation induced by combination of EGF and androgen suggesting a role of AR in the effects of EGF. The role of AR was further assessed by determining the effect of EGF on AR binding directly. It was shown that EGF stimulated androgen binding activity of the male fetal reproductive tract cells significantly by increasing the number of binding sites by 3-fold with slight decrease in binding affinity. Thus, it appears that AR plays a role in mediating EGF-modulation of sexual differentiation.

The role of growth hormone in fetal mouse reproductive tract differentiation.

Although GH plays a key role in postnatal growth and differentiation, its role in fetal differentiation is not clear at the present. The aim of the present study was to investigate whether GH plays a role in fetal sexual differentiation, and we used in vitro organ culture assay of sexual differentiation to determine this. The results showed that anti-rGH antibody blocked Wolffian duct differentiation specifically in the presence of fetal testes. Exogenous GH supplemented in the above experiment reversed the blocking effect of anti-GH. Among the other related products, insulin-like growth factor I was highly effective in reversing the anti-GH effect, insulin-like growth factor II was partially effective, but PRL was unable to reverse the anti-GH effect. GH itself was found to produce some masculinizing effect, as demonstrated by its ability to stabilize the Wolffian duct in female fetuses. The role of GH was further demonstrated by the observation that GH-immunoreactive material of the size of authentic GH was detected in the 18-day fetal reproductive tract, and the concentration of this material increased in response to progression of sexual differentiation. Determination of androgen-binding activity using Scatchard analysis on the cells isolated from the 18-day fetal reproductive tract indicated that androgen-binding activity increased after GH treatment of the cells. Thus, it may be concluded that GH influences male sexual differentiation and alters the androgen-binding activity of the fetal reproductive tract.

The androgen receptor gene mutations database.

The current version of the androgen receptor (AR) gene mutations database is described. We have added (if available) data on the androgen binding phenotype of the mutant AR, the clinical phenotype of the affected persons, the family history and whether the pathogenicity of a mutation has been proven. Exonic mutations are now listed in 5'-->3' sequence regardless of type and single base pair changes are presented in codon context. Splice site and intronic mutations are listed separately. The database has allowed us to substantiate and amplify the observation of mutational hot spots within exons encoding the AR androgen binding domain. The database is available from EML (ftp://www.ebi.ac.uk/pub/databases/androgen) or as a Macintosh Filemaker file (MC33@musica.mcgill.ca).

Hepatic expression of sex hormone-binding globulin associated with the postnatal surge of serum androgen-binding activity in the Djungarian hamster

Serum androgen-binding capacity in Djungarian hamsters, as in many other mammals, increases within days after birth and remains elevated until puberty. This increased activity has been attributed to a hepatic glycoprotein, sex hormone-binding globulin (SHBG), but expression of SHBG by the postnatal liver has not been demonstrated. Therefore, a full-length SHBG cDNA was cloned from the liver of neonatal hamsters and the expression of SHBG during development was examined. Hepatic SHBG RNA levels, as measured by both competitive RT-PCR and Northern analysis, were very low in fetal animals but increased significantly within 24 h of birth. Maximal values were maintained for 1 week after parturition, and then declined to basal adult levels. The developmental pattern in hepatic SHBG immunoactivity, as determined by Western analysis, mirrored that of hepatic SHBG mRNA. However, changes in serum SHBG immunoactivity and steroid-binding activity occurred approximately 1 week later. There were no sex differences in the levels of hepatic SHBG mRNA or protein during development, but serum immunoactivity tended to be higher in females at puberty. Sex- and age-related differences in the relative abundance of SHBG isoforms were also noted. Results of these studies demonstrate that Djungarian hamsters express an authentic SHBG and indicate that the postnatal surge in serum androgen-binding activity is due to perinatal up-regulation of SHBG expression.

Androgen-Directed Development of the Xenopus laevis Larynx: Control of Androgen Receptor Expression and Tissue Differentiation

The larynx of adult male Xenopus laevis differs markedly from that of the female; masculinization of the larynx requires androgen secretion during postmetamorphic development. Early in postmetamorphic development, androgen stimulates laryngeal cell proliferation and androgen binding activity is high. Later, androgen induces laryngeal cell differentiation and binding levels decrease. Here we explore the relation between laryngeal differentiation and androgen receptor expression. In untreated females, the larynx expresses high levels of androgen receptor mRNA early in postmetamorphic life; levels decline as females mature. The highest level of androgen receptor message is found in the undifferentiated laryngeal elastic precartilage of both sexes. When juveniles are exposed to androgen, laryngeal cell proliferation is stimulated within 48 hr in both sexes. Short exposures to androgen result in a biphasic response of AR mRNA levels; a marked down-regulation (4 hr) is followed by recovery at 8 hr (males) or 48 hr (females). Following longer periods of androgen treatment (3 weeks), AR mRNA expression is down-regulated and male-typical differentiation of elastic cartilage is induced in both sexes. Thus laryngeal growth responses to androgen are closely related to expression levels of androgen receptor mRNA.

Characterization of alternative amino acid substitutions at arginine 830 of the androgen receptor that cause complete androgen insensitivity in three families.

We have studied two different missense mutations at arginine-830 in exon 7 of the human androgen receptor (hAR) gene that cause complete androgen insensitivity (CAIS) in three families. These substitutions result from point mutations at nucleotide 2489: a G-->T transversion causes Arg830Leu and a G-->A transition causes Arg830Gln. Genital skin fibroblasts of the patients have negligible androgen-binding capacity. The mutations were recreated in an hAR cDNA expression vector that was transiently transfected into COS-1 cells. Both mutant androgen receptors have increased dissociation rate constants and apparent equilibrium rate constants when measured with 5 alpha-dihydrotestosterone or the synthetic, nonmetabolizable androgens, mibolerone or methyltrienolone. The mutant androgen-binding activities share a distinctive thermal misbehavior. At 37 degrees C R830Q and R830L are about 40% and 10% of normal, respectively. At 22 degrees C both mutants gain androgen binding while the normal decreases by 20%; for R830Q the augmented value approaches 60% of the normal. During prolonged 18 h incubation at 37 degrees C, androgen binding of the normal AR is stable while that of both mutants decreases by at least 85%. Both mutants have a very reduced ability to transactivate a cotransfected androgen-responsive reporter gene, but R830Q is better than R830L. We conclude that arginine-830 is important for A-R complex stability, and that its replacement by glutamine or leucine yields distinctive functional aberrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Substitution of arginine-839 by cysteine or histidine in the androgen receptor causes different receptor phenotypes in cultured cells and coordinate degrees of clinical androgen resistance.

We aim to correlate point mutations in the androgen receptor gene with receptor phenotypes and with clinical phenotypes of androgen resistance. In two families, the external genitalia were predominantly female at birth, and sex-of-rearing has been female. Their androgen receptor mutation changed arginine-839 to histidine. In a third family, the external genitalia were predominantly male at birth, and sex-of-rearing has been male: their codon 839 has mutated to cysteine. In genital skin fibroblasts, both mutant receptors have a normal androgen-binding capacity, but they differ in selected indices of decreased affinity for 5 alpha-dihydrotestosterone or two synthetic androgens. In transiently cotransfected androgen-treated COS-1 cells, both mutant receptors transactivate a reporter gene subnormally. The His-839 mutant is less active than its partner, primarily because its androgen-binding activity is more unstable during prolonged exposure to androgen. Adoption of a nonbinding state explains a part of this instability. In four other steroid receptors, another dibasic amino acid, lysine, occupies the position of arginine-839 in the androgen receptor. Androgen receptors with histidine or cysteine at position 839 are distinctively dysfunctional and appear to cause different clinical degrees of androgen resistance.

Antagonism of androgen action in prostate tumor cells by retinoic acid

Recent studies have demonstrated that retinoic acid (RA) can repress the growth of human prostatic epithelial cells. Since the proliferation of prostate cells is highly dependent on androgen stimulation, presumably via its cognate receptor, we investigated the effects of RA on the expression of the androgen receptor and other androgen-regulated genes in the human prostatic adenocarcinoma cell line LNCaP. Using a radioligand binding assay, we found that androgen-binding activity was reduced 30-40% in cells treated with 10(-5) M RA plus 6 nM dihydrotestosterone (DHT), as compared to cells with the androgen alone. Moreover, the reduction of the androgen receptor (AR) was not accompanied by alteration of the ligand-binding affinity. Concomitant changes in the function of AR were manifested by a dramatic reduction in AR-mediated transcription activity in a transfection experiment. Androgen-induced levels of both prostate-specific antigen (PSA) and human glandular kallikrein-1 (hKLK2) mRNAs were significantly repressed by RA in a dose- and time-dependent manner. Consistent with this finding, androgen induction of PSA glycoprotein was also repressed by RA, with maximal inhibition occurring at 10(-5) M. These data suggest that the suppression of proliferation and function of prostatic cells by RA may be via modulatory effects on the AR.

Molecular prenatal diagnosis of partial androgen insensitivity syndrome based on the Hind III polymorphism of the androgen receptor gene.

Partial androgen insensitivity syndromes are the cause of genital ambiguity that is at times quite severe; there is, therefore, a high demand for prenatal diagnosis in families already afflicted with this syndrome. When the mutation has not been identified, the diagnosis can be made by the study of the polymorphisms of the androgen receptor gene. To perform molecular prenatal diagnosis in a family with partial androgen insensitivity syndrome, we studied the Hind III polymorphism of the androgen receptor gene on the trophoblastic DNA. The use of this restriction fragment length polymorphism tracked maternal X chromosome segregation and established prenatal diagnosis although the mutation had not yet been identified in this family. FAMILY: The mother had been previously described as heterozygous for the Hind III polymorphism and chromosomal segregation analysis showed that the affected allele was associated with the 6.7-kb Hind III fragment. Hind III RFLP with an androgen receptor gene cDNA probe was realized on the trophoblastic DNA, along with measurement of androgen binding activity on the trophoblastic cells. We detected the presence of the 6.7-kb fragment in the DNA of the trophoblastic cells suggesting the fetus was affected. Partial androgen insensitivity syndrome was confirmed by a considerable decrease in androgen binding activity on the trophoblastic cells and by sonography of the fetus. After a therapeutic abortion requested by the parents, the diagnosis was confirmed by clinical examination of the fetus, biochemical analyses of the fetal androgen receptor, and molecular studies of the fetal DNA. When the mutation of the androgen receptor gene has not been identified, Hind III polymorphism of the trophoblastic DNA is useful in the prenatal diagnosis of androgen insensitivity syndrome in high-risk families.

Androgen receptor in human liver: Characterization and quantitation in normal and diseased liver

Liver is responsive to sex hormones. The role of androgens in normal human liver function is not well understood, although androgens have been implicated in several liver diseases. Because the human hepatic androgen receptor has not been adequately characterized, we analyzed cytosolic and nuclear fractions from normal human liver of both sexes for androgen-binding activity using multipoint saturation analysis with the androgenic radioligand methyltrienelone (R1881). Both cytosolic and nuclear fractions of both sexes displayed high affinity R1881 binding (dissociation constants = nanomolar range). The R1881 binding in both fractions is highly specific in that potent androgens compete well, and the antiandrogens hydroxyflutamide and cyproterone acetate show partial competition; other nonandrogenic steroid hormones do not compete. The cytosolic R1881 receptor displays physicochemical characteristics of androgen receptors in other tissues in that it is retained by heparin-Sepharose and by DNA cellulose after activation, and it displays a molybdate-stabilized 8S form on sucrose gradients and a 7.3-nm species on gel filtration chromatography. Receptor activity was also quantitated in specimens of hepatic adenoma, focal nodular hyperplasia and metastatic carcinoma to the liver and in samples of adjacent histologically normal specimens when available. In general, both the diseased and normal portions of the livers from the patients with hepatic adenoma and metastatic carcinoma to the liver, but not focal nodular hyperplasia, demonstrated reduced total androgen-receptor activity as compared with liver from normal individuals.(ABSTRACT TRUNCATED AT 250 WORDS)