Binding of androgens in 5α-reductase-deficient human genital skin fibroblasts: inhibition by progesterone and its metabolites

1982 ◽  
Vol 94 (3) ◽  
pp. 415-427 ◽  
Author(s):  
M. B. Hodgins
Keyword(s):  
Androgen Receptor ◽  
Androgen Receptors ◽  
Cultured Cells ◽  
Reductase Activity ◽  
External Genitalia ◽  
Skin Fibroblasts ◽  
Urogenital Sinus ◽  
Receptor Complexes ◽  
High Affinity ◽  
Receptor Sites

Binding of [3H]testosterone and 5α-dihydro[3H]testosterone ([3H]DHT) to specific androgen-receptor sites of 5α-reductase-deficient human genital skin fibroblasts (five cell-lines) was studied in the intact cultured cells at 37 °C. Under the conditions of the experiments, conversion of [3H]testosterone into [3H]DHT was negligible. Both steroids bound to the same set of high-affinity saturable sites in cytoplasmic and nuclear fractions of the cells. Unlabelled testosterone, DHT and methyltrienolone competed effectively with the labelled steroids. Progesterone and oestradiol were weaker competitors; cortisol did not compete. The dissociation constant (Kd) for high-affinity complexes with [3H]testosterone (0·44 ± 0·035 nmol/l) was higher than that for [3H]DHT complexes (0·20 ± 0·090 nmol/l). Unlabelled DHT was more effective than unlabelled testosterone in competing with either radioactive steroid. Complexes of [3H]DHT and receptor dissociated more slowly than [3H]testosterone-receptor complexes and [3H]DHT bound more extensively to low-affinity non-saturable sites in fibroblasts. As judged by competition with the radioactive androgens, progesterone bound to the androgen receptor with a Kd of about 7 nmol/l. 5α-Pregnane-3,20-dione had an approximately fivefold lower affinity than progesterone for androgen receptors; 3α/β- or 20α-reduction lowered its affinity further. It is suggested that in 5α-reductase deficiency in man, progesterone in amniotic fluid and blood could effectively inhibit testosterone binding to androgen receptors in the male embryonic external genitalia. One function of the high levels of 5α-reductase activity normally found in embryonic external genitalia and urogenital sinus may be to protect these tissues from the potentially antiandrogenic action of progesterone.

Evidence for an androgen receptor in porcine Leydig cells

1987 ◽  
Vol 115 (1) ◽  
pp. 119-124 ◽  
Author(s):  
Veli Isomaa ◽  
Mauri Orava ◽  
Reijo Vihko
Keyword(s):  
Androgen Receptor ◽  
Binding Sites ◽  
Leydig Cells ◽  
Androgen Receptors ◽  
Cultured Cells ◽  
Binding Specificity ◽  
Culture Conditions ◽  
High Affinity ◽  
The Mean ◽  
Steroid Binding

Abstract. Cytosol and nuclear androgen receptor concentrations were measured in freshly prepared and cultured Leydig cells of immature pig testis with exchange assays using [3H]methyltrienolone as labelled ligand. Androgen receptors in Leydig cells had high affinity for [3H]methyltrienolone and steroid binding specificity typical of an androgen receptor. The mean receptor concentrations were 76 fmol/mg protein and 210 fmol/mg DNA for cytosol and nuclei, respectively. In sucrose gradients, cytosol androgen receptors sedimented in the 4 S region. The cells maintained androgen receptors under culture conditions. Exposure of cultured cells to [3H]methyltrienolone (10 nmol/l) resulted in accumulation of androgen receptors in the nuclei with maximal uptake by 1 h. We conclude that methyltrienolone binding sites with characteristics of androgen receptors were identified in both cytosol and nuclei of porcine Leydig cells.

CHARACTERIZATION AND ASSAY OF THE PROGESTERONE RECEPTOR IN RAT UTERINE CYTOSOL

1978 ◽  
Vol 76 (1) ◽  
pp. 21-31 ◽  
Author(s):  
M. T. VU HAI ◽  
E. MILGROM
Keyword(s):  
Progesterone Receptor ◽  
Receptor Complexes ◽  
High Affinity ◽  
Receptor Sites ◽  
Natural Hormone ◽  
Corticosteroid Binding Globulin ◽  
Steroid Binding Proteins ◽  
Steroid Binding ◽  
High Concentrations ◽  
Synthetic Progestogen

SUMMARY The synthetic progestogen R5020 (17,21-dimethyl-19-norpregna-4,9-diene-3,20-dione) binds with high affinity (Ka = 8·8 × 108 1/mol at 0 °C) to the progesterone receptor from rat uterine cytosol. At nanomolar concentrations, equilibrium is attained in less than 90 min. R5020 has a very low affinity for other specific steroid-binding proteins (corticosteroid-binding globulin and oestrogen receptors) present in relatively high concentrations in the uterine cytosol. The affinity of the receptor for the natural hormone progesterone is remarkably low (Ka= 1 × 108−1·7 × 1081/mol at 0 °C) which explains the instability of progesterone–receptor complexes. Advantage may be taken of this property to remove endogenous progesterone easily by charcoal treatment at 0 °C, a treatment which does not modify the concentration of receptors. A method based on these characteristics is described for the assay of the total number (progesterone-bound and unbound) of receptor sites in uterine cytosol. This assay may be used in various physiological situations where endogenous progesterone is present at unknown concentrations.

ANDROGEN RECEPTORS IN PROLACTIN PRODUCING PITUITARY TUMOURS IN RATS

1977 ◽  
Vol 86 (2) ◽  
pp. 288-298 ◽  
Author(s):  
Arne Attramadal ◽  
Oddvar Naess ◽  
Egil Haug ◽  
Vidar Hansson ◽  
Ken Purvis
Keyword(s):  
Androgen Receptor ◽  
Binding Sites ◽  
Androgen Receptors ◽  
Sedimentation Coefficient ◽  
Ventral Prostate ◽  
Scatchard Analysis ◽  
Receptor Complex ◽  
Pituitary Tumours ◽  
High Affinity ◽  
Androgen Binding

ABSTRACT The androgen receptor system in prolactin secreting oestrogen induced pituitary tumours has been studied. The tumour cytosol was found to contain specific androgen receptors binding [3H]5α-dihydrotestosterone (DHT) and [3H] testosterone (T) with high affinity and low capacity. Scatchard analysis of the saturation data for T revealed one class of high affinity binding sites. The equilibrium constant of dissociation (Kd) was ∼ 4 × 10−10 m and the number of binding sites was calculated to be 12.8 femtomoles/mg protein. The sedimentation coefficient of the androgen receptor complex in low salt sucrose gradients was ∼ 7 S, the electrophoretic mobility (RF) in 3.25 % polyacrylamide gels ∼ 0.5 and the isoelectric point 5.8. The protein nature of the receptor was indicated by the finding that protease, but not DNase and RNase, eliminated androgen binding. Furthermore, the receptor was thermolabile and functionally dependent on free SH-groups since androgen binding was eliminated by heating 45°C for 30 min) and treatment with p-chloromercuriphenyl sulphonate (1 mm). Steroid specificity was tested in vitro by examining the competing efficiency of different unlabelled steroids for the binding of [3H]T. The affinity of DHT for the receptor was approximately twice that of testosterone while the binding affinity of oestradiol-17β and progesterone was very low. Cortisol had no affinity for the androgen receptor. The dissociation of the androgen receptor complex was very slow at 0°C (t ½ > 48 h). Thus, the characteristics of the cytoplasmic androgen receptors of the prolactin producing pituitary tumours are very similar to those of the androgen receptors earlier demonstrated in the anterior pituitary, hypothalamus, ventral prostate, epididymis and testis. The presence of specific androgen receptors in prolactin producing pituitary tumours indicates that androgen is involved in the regulation of synthesis and release of prolactin.

scholarly journals Physiological Role for the Cochaperone FKBP52 in Androgen Receptor Signaling

2005 ◽  
Vol 19 (6) ◽  
pp. 1654-1666 ◽  
Author(s):  
Joyce Cheung-Flynn ◽  
Viravan Prapapanich ◽  
Marc B. Cox ◽  
Daniel L. Riggs ◽  
Carlos Suarez-Quian ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Physiological Role ◽  
External Genitalia ◽  
Steroid Receptor ◽  
Isomerase Activity ◽  
Physiological Importance ◽  
Fk506 Binding Protein ◽  
Receptor Complexes ◽  
Reproductive Tissues ◽  
Prostate Epithelial Cells

Abstract Molecular chaperones mediate multiple aspects of steroid receptor function, but the physiological importance of most receptor-associated cochaperones has not been determined. To help fill this gap, we targeted for disruption the mouse gene for the 52-kDa FK506 binding protein, FKBP52, a 90-kDa heat shock protein (Hsp90)-binding immunophilin found in steroid receptor complexes. A mouse line lacking FKBP52 (52KO) was generated and characterized. Male 52KO mice have several defects in reproductive tissues consistent with androgen insensitivity; among these defects are ambiguous external genitalia and dysgenic prostate. FKBP52 and androgen receptor (AR) are coexpressed in prostate epithelial cells of wild-type mice. However, FKBP52 and AR are similarly coexpressed in testis even though testis morphology and spermatogenesis in 52KO males are usually normal. Molecular studies confirm that FKBP52 is a component of AR complexes, and cellular studies in yeast and human cell models demonstrate that FKBP52 can enhance AR-meditated transactivation. AR enhancement requires FKBP52 peptidylprolyl isomerase activity as well as Hsp90-binding ability, and enhancement probably relates to an affect of FKBP52 on AR-folding pathways. In the presence of FKBP52, but not other cochaperones, the function of a minimally active AR point mutant can be dramatically restored. We conclude that FKBP52 is an AR folding factor that has critically important physiological roles in some male reproductive tissues.

scholarly journals Coexpression of Wilms’ tumor suppressor 1 (WT1) and androgen receptor (AR) in the genital tract of human male embryos and regulation of AR promoter activity by WT1

2007 ◽  
Vol 38 (5) ◽  
pp. 547-554 ◽  
Author(s):  
Birgit Köhler ◽  
Anne-Lise Delezoide ◽  
Brigitte Boizet-Bonhoure ◽  
Michael J McPhaul ◽  
Charles Sultan ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Tumor Suppressor ◽  
Wilms Tumor ◽  
External Genitalia ◽  
Cell System ◽  
Urogenital Sinus ◽  
Local Factor ◽  
Human Male ◽  
Regulatory Effects ◽  
Male External Genitalia

The Wilms’ tumor suppressor 1 (WT1) is one of the key regulators of early male genital development. The androgen receptor (AR) is the major local factor responsible for the development of the male genitalia. As a subset of patients, with WT1 mutations and virilization defects, were found to present normal testosterone producing testes after birth, which suggests androgen resistance, we hypothesized that WT1 and AR might functionally interact during the development of the external genitalia. Coexpression of WT1 and AR was found in the mesenchyme surrounding the urogenital sinus, the mesonephros, and the Müllerian duct at 7 weeks p.c. and in the epididimys, vas deferens, and the gubernaculum testes from 13 to 27 weeks p.c. in human male embryos. A modification of AR expression by WT1 (WT1+/+, WT1+/−, and WT1+/− R394W) was seen in CV1, Hela, LNCaP, and T293 cells. WT1 was shown to increase or decrease AR expression depending on the cell line (1.6- to 3.7-fold). In this study, we consider LNCaP and T293 cells as the most physiological cell system, as both originate from the human urogenital tract. In these cell lines, a repressional effect of the mutant WT1+/− R394W (0.5-fold) on AR expression in comparison to the wild-type WT1+/− could be demonstrated. From our data, we conclude that a functional interaction of WT1 and AR might play a role during the development of the male external genitalia, but as the regulatory effects were moderate most likely in concert with other local cofactors.

The state transitions of normal and mutant androgen-receptor complexes in human genital skin fibroblasts

1990 ◽  
Vol 36 (6) ◽  
pp. 651-657 ◽  
Author(s):  
Morris Kaufman ◽  
Leonard Pinsky ◽  
Bruce Gottlieb ◽  
Mark Trifiro
Keyword(s):  
Androgen Receptor ◽  
The State ◽  
Skin Fibroblasts ◽  
State Transitions ◽  
Receptor Complexes

scholarly journals Unoccupied nuclear oestradiol-receptor sites in normal human endometrium

1980 ◽  
Vol 185 (3) ◽  
pp. 733-738 ◽  
Author(s):  
C Lévy ◽  
R Mortel ◽  
B Eychenne ◽  
P Robel ◽  
E E Baulieu
Keyword(s):  
Significant Proportion ◽  
Human Endometrium ◽  
Endogenous Hormones ◽  
Association Rate ◽  
Affinity Ligands ◽  
Receptor Complexes ◽  
High Affinity ◽  
Receptor Sites ◽  
Normal Human ◽  
Kinetics Of

The existence of unoccupied nuclear oestradiol-receptor sites in normal human endometrium was investigated. Nuclei were prepared from endometrial samples obtained by curettage and exposed to [3H]oestradiol, which became maximmaly bound at 0 degrees C within 1 h. This result contrasted with the binding kinetics of oestradiol-receptor complexes, since the exchange of hormone took at least 3 h at 30 degrees C and no displacement occurred at 0 degrees C. Before concluding that the nuclear sites were unoccupied, the presence of endogenous low-affinity ligands was excluded, because the association rate of oestradiol was unchanged after nuclei were stripped from their putative ligands, and the displacement of oestrone bound to nuclear receptor by oestradiol was very slow at 0 degrees C. The available sites had high affinity for oestradiol (KD 1.3 nM) and binding-specificity characteristics of oestradiol receptors. Similar results were observed with crude and purified nuclear preparations. It was concluded that a significant proportion of nuclear oestradiol receptors in normal human endometrium is unoccupied by endogenous hormones.

Endothelin: localization, synthesis, activity, and receptor types in human penile corpus cavernosum

1991 ◽  
Vol 261 (4) ◽  
pp. H1078-H1085 ◽  
Author(s):  
I. Saenz de Tejada ◽  
M. P. Carson ◽  
A. de las Morenas ◽  
I. Goldstein ◽  
A. M. Traish
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Cultured Cells ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Corpus Cavernosum ◽  
High Affinity ◽  
Cells In Culture ◽  
Receptor Sites ◽  
Competition Binding

The localization, synthesis, and activity of endothelin and the receptor types mediating its effects in penile corpus cavernosum were investigated in whole tissue and in cultured cells derived from this tissue. With immunocytochemistry, utilizing an antiendothelin 1 (ET-1) monoclonal antibody, endothelin-like immunoreactivity was localized intensely in the endothelium and to a lesser degree in the trabecular smooth muscle. Human corpus cavernosum endothelial cells in culture expressed preproendothelin 1 mRNA, as determined by Northern blot analysis. Significant amounts of endothelin-like immunoreactivity were measured by radioimmunoassay in the supernatants of corpus cavernosum endothelial cells in culture. Endothelins are potent constrictors and caused long-lasting contractions of corporeal strips in organ chambers. Equilibrium binding analysis of endothelins to their receptor sites revealed high-affinity, specific, and saturable binding of labeled endothelins to corporeal membranes. Competition binding experiments demonstrated receptors with high affinity for ET-1 and -2 and low affinity for ET-3 and another, less abundant, set of receptors with high affinity for ET-1, -2, and -3. Affinity labeling of endothelins to corporeal membranes, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, revealed that ET-1 and -2 cross-linked specifically to three different molecular mass components (75, 52, and 34 kDa). ET-3 bound only to the 34-kDa component. It is concluded that human corpus cavernosum endothelium has the ability to synthesize and release endothelin, that endothelins contract corporeal smooth muscle, and that at least two distinct endothelin receptors may exist and are differentiated by their affinity for ET-3.

Androgen resistance syndromes

1982 ◽  
Vol 243 (2) ◽  
pp. E81-E87 ◽  
Author(s):  
J. E. Griffin ◽  
M. Leshin ◽  
J. D. Wilson
Keyword(s):  
Androgen Receptor ◽  
Reductase Activity ◽  
External Genitalia ◽  
Later Life ◽  
Ambiguous Genitalia ◽  
Testicular Feminization ◽  
Developmental Defects ◽  
Androgen Action ◽  
Normal Men ◽  
Sites Of Action

Hereditary defects that impede androgen action cause resistance to the hormone both during embryogenesis and in later life and hence usually cause developmental defects of the male urogenital tract. In genetic males such defects produce a phenotypic spectrum ranging from infertile but otherwise normal men to individuals with varying degrees of ambiguous genitalia to phenotypic women. These disorders can be classified on the basis of the step in androgen action that is impeded by the individual mutations. 5 alpha-Reductase deficiency is an autosomal recessive enzyme defect that impairs the conversion of testosterone to dihydrotestosterone. The internal male genital tract virilizes normally, but the external genitalia are predominantly female in character. The syndrome is the result of one of several mutations that impair the function of the 5 alpha-reductase enzyme. A variety of disorders influence the androgen receptor that mediates the action of both testosterone and dihydrotestosterone. At least four phenotypic variants can be distinguished: complete testicular feminization, incomplete testicular feminization, the Reifenstein syndrome, and the infertile male syndrome, each of which is inherited as an X-linked trait. Absence of receptor binding is found commonly in complete testicular feminization, but qualitative and/or less severe quantitative defects in receptor function can be associated with all four variants. A third type of disorder, receptor positive resistance, also causes variable defects in male development and is associated with normal 5 alpha-reductase activity and normal androgen receptor. The underlying defect is presumed to lie at the intranuclear site or sites of action of the hormone-receptor complex.

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