RESUMO
PROBLEM: To determine whether prostatein, the major protein produced and secreted into the seminal fluid by the rat ventral prostate has any effect on the phagocytic cell functions in vitro. METHOD OF STUDY: Analysis was done by determining if purified prostatein added to cells obtained from the peritoneal cavity has any effect on their phagocytic and intracellular killing capacity. Also, we analyzed the effect of prostatein on the production of oxygen and nitrogen intermediates, measuring these metabolites by Nitroblue tetrazolium assay and by the Griess reaction respectively. RESULTS: Prostatein possess the ability to inhibit in vitro the phagocytic and killing properties of peritoneal rat leukocytes in a dose-dependent manner. The addition of a polyclonal antiserum against prostatein specifically blocks this inhibitory effect. Moreover, prostatein inhibits the production of oxygen and nitrogen intermediates by these cells. CONCLUSION: Regulation of the production of reactive oxygen species in the reproductive tract is extremely necessary to avoid their deleterious effects on the sperm motility and the fertilization process. We propose that prostatein, a protein supplied by an accessory gland like prostate, can inhibit the macrophage function, showing an important antioxidant effect.
Assuntos
Proteína de Ligação a Androgênios/farmacologia , Fagócitos/imunologia , Proteína de Ligação a Androgênios/fisiologia , Proteína de Ligação a Androgênios/toxicidade , Animais , Líquido Ascítico/citologia , Líquido Ascítico/metabolismo , Relação Dose-Resposta a Droga , Feminino , Leucócitos/química , Masculino , Fagócitos/citologia , Fagócitos/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Próstata/química , Prostateína , Ratos , Ratos Wistar , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Secretoglobinas , Sêmen/química , UteroglobinaRESUMO
In a previous study, we showed that nonobese diabetic (NOD) mice, a strain that present an inherited predisposition to develop both spontaneous and induced autoimmune lesions, are susceptible to the induction of experimental autoimmune prostatitis (EAP), developing a severe inflammatory reaction in the prostate, accompanied by humoral and T-cell-mediated responses. In this study we asked whether the protein steroid binding protein (PSBP) or prostatein (a major autoantigen in the rat model of EAP) is a potential autoantigen in the NOD mouse model and examined the ability of purified PSBP to induce EAP in this strain. Our results indicate clearly that NOD male mice react immunologically to PSBP by developing lymphocytic inflammatory lesions in prostatic tissue and producing both a cellular- and humoral-specific autoimmune response. But our results suggest also the existence of other prostatic autoantigens present only in total prostate extract. Such additional antigens could enhance the autoimmune response and result in more severe forms of inflammation. We also analyzed the respective contributions of MHC antigens and CD4/CD8 T-cell subsets in NOD mice lacking expression of beta 2-microglobulin (NOD.beta2m degrees/degrees) or MHC class II beta chain (NOD.Abeta degrees/degrees) and demonstrate an essential role for CD4(+) T cells in the development of EAP in the NOD model. In conclusion, we demonstrate that PSBP is an autoantigen recognized by the NOD immune system, capable of generating humoral and cellular autoimmune responses and of inducing EAP. Moreover, using selected knock-out NOD mice we demonstrate an essential role for CD4(+) T cells in the development of EAP.
Assuntos
Proteína de Ligação a Androgênios/imunologia , Doenças Autoimunes/etiologia , Prostatite/etiologia , Animais , Autoanticorpos/sangue , Autoantígenos , Doenças Autoimunes/imunologia , Doenças Autoimunes/patologia , Linfócitos T CD4-Positivos/imunologia , Antígenos de Histocompatibilidade Classe II/genética , Imunização , Técnicas In Vitro , Cinética , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos NOD , Camundongos Knockout , Prostateína , Prostatite/imunologia , Prostatite/patologia , Secretoglobinas , Uteroglobina , Microglobulina beta-2/deficiência , Microglobulina beta-2/genéticaRESUMO
Prostatic steroid binding protein (PSBP) is the major protein produced ( approximately 20% of the total cytosolic protein) and secreted into the seminal fluid by the rat ventral prostate but its physiological function has not been elucidated yet. Since PSBP is secreted into the seminal fluid (which is itself a potent immunosuppressor) and has strong homology with uteroglobin (which possess an important anti-inflammatory function) our aim was to determine what effect, if any, PSBP would have on the immune system. With that purpose in mind we performed mononuclear cell cultures in the presence or absence of purified PSBP and analysed the effect of this protein on different functional parameters. PSBP inhibits the mitogen-induced proliferation of normal rat spleen mononuclear cells (MNC) specifically and in a dose-dependent manner. It reduces the production of IL-2 and the expression of its receptor (analysed by flow cytometry) which are important events for lymphocyte proliferation. Also, PSBP was able to inhibit OVA-specific proliferation of lymph node cells from previously primed animals. The immunosuppressive effect of PSBP is not due to an inherent toxic effect to the cells, since the cell viability was kept intact at the different times of culture studied. We also analysed the effect of rat PSBP on mitogen-induced proliferation of mouse spleen and human blood MNC. The proliferation was strongly abolished in a dose-dependent and non-species specific fashion. Moreover, PSBP strongly inhibits the human mixed lymphocyte reaction. Taken together, the present data support evidence for a new type of function for PSBP. We report that PSBP is a potent immunosuppressor factor and we describe its effect on the immune function in vitro. Here, we discuss the possible implications of these findings in the protection of sperm from immunologic damage in the feminine reproductive tract.
Assuntos
Proteína de Ligação a Androgênios/farmacologia , Imunossupressores/farmacologia , Próstata/imunologia , Proteína de Ligação a Androgênios/imunologia , Proteína de Ligação a Androgênios/isolamento & purificação , Animais , Antígenos/administração & dosagem , Regulação para Baixo/efeitos dos fármacos , Feminino , Humanos , Imunossupressores/isolamento & purificação , Técnicas In Vitro , Interleucina-2/metabolismo , Ativação Linfocitária/efeitos dos fármacos , Teste de Cultura Mista de Linfócitos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Mitógenos/farmacologia , Ovalbumina/imunologia , Proteína de Ligação a Fosfatidiletanolamina , Prostateína , Ratos , Ratos Wistar , Receptores de Interleucina-2/metabolismo , Secretoglobinas , Espermatozoides/imunologia , UteroglobinaRESUMO
Experimental autoimmune prostatitis (EAP) is a disease that could be considered an experimental model of human non-bacterial prostatitis. In this experimental model, male rats are intradermally immunized with a saline extract of male sex accessory glands (RAG) in an adequate adjuvant. The prostatitis observed in the immunized animals develops as a consequence of the immune response against RAG antigens, and the histological lesion is strikingly similar to the pattern of prostatic inflammation observed in the human disease. In this study, we purified one of the prostatic autoantigens recognized by the autoantibodies in our model. Amino acid sequence analysis identified the purified protein as prostatein or rat prostatic steroid binding protein, a member of the uteroglobin superfamily. Prostatein was recognized not only by the humoral autoimmune response, but also by the cellular autoimmune response. Certainly, the DTH response and lymph node cell proliferative assays against prostatein in immunized animals yielded positive results. Prostatein is not only the target of the autoimmune response in animals immunized with the whole extract, but also an inducing antigen of the disease. Purified prostatein, when incorporated to an adequate adjuvant, elicited cellular and humoral autoimmune response and lesion in the prostate gland. The identification of one of the target antigens in autoimmune prostatitis has provided a further refinement and characterization of our model, which could serve for a better understanding of the aetiology, pathogenesis and pathophysiology of non-bacterial prostatitis.
Assuntos
Proteína de Ligação a Androgênios/imunologia , Autoantígenos/imunologia , Prostatite/imunologia , Animais , Citosol/imunologia , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Humanos , Imunidade Celular , Masculino , Peso Molecular , Proteína de Ligação a Fosfatidiletanolamina , Próstata/imunologia , Prostateína , Ratos , Ratos Wistar , Secretoglobinas , UteroglobinaRESUMO
The human androgen receptor is a member of the superfamily of steroid hormone receptors and contains three functional domains: an amino-terminal region involved in the expression of androgen regulated genes, a central cystein-rich DNA binding region and a carboxy-terminal hormone binding region. Proper functioning of this protein is a prerequisite for normal male sexual differentiation and development. Androgen action is currently studied in vitro, using fibroblasts culture from genital skin and complementary DNA of the androgen receptor gene has been recently cloned and sequenced. During recent years a substantial progress has been made elucidating the structure-function relationship of the androgen receptor and the characterization of the molecular defects associated with androgen insensitivity syndromes. There appears to be a broad correlation between the degree of receptor dysfunction caused by the mutation and the patient phenotype
Assuntos
Humanos , Masculino , Proteína de Ligação a Androgênios/fisiologia , Receptores Androgênicos/genética , Transtornos do Desenvolvimento Sexual/genética , Di-Hidrotestosterona/farmacocinética , 3-Oxo-5-alfa-Esteroide 4-Desidrogenase/deficiênciaRESUMO
In plasma, most steroid hormones are bound and transported by the specific binding protein, testosterone-estradiol-binding globulin (TeBG). For years, it was believed that the only function of this protein was to regulate the concentration of free steroids in plasma. However, a number of reports have provided evidence for the presence of specific TeBG receptors on plasma membranes. Furthermore, the interaction of TeBG with its receptor was shown to be inhibited when steroids are bound to TeBG, suggesting that TeBG is an allosteric protein. The purpose of this manuscript is to review the evidence that androgen-binding proteins bind to membrane receptors, and, in some cells, this binding stimulates cAMP accumulation, and transfer TeBG/ABP into tissue as a consequence of receptor mediated endocytosis. Recent studies from our laboratories have demonstrated binding and uptake of TeBG by MCF-7 breast cancer cells. The interaction of unligated rabbit TeBG with membranes from MCF-7 cells resulted in a time and concentration-dependent increase in adenylate cyclase activity. The TeBG alone also had a reproducible effect on intact cells by increasing cAMP accumulation by 30-35%. The addition of DHT to cells, after TeBG has been allowed to bind, resulted in increases in cAMP of greater than 4-fold. This effect was not blocked by antiandrogens. These data support the hypothesis that extracellular SHBG is a regulator of cellular function through a membrane receptor that is coupled to adenylate cyclase.
Assuntos
Proteína de Ligação a Androgênios/metabolismo , Receptores de Superfície Celular/metabolismo , Globulina de Ligação a Hormônio Sexual/metabolismo , Adenilil Ciclases/metabolismo , Animais , AMP Cíclico/metabolismo , Di-Hidrotestosterona/farmacologia , Endocitose , Humanos , Coelhos , Transdução de SinaisRESUMO
We have explored the morphogenic and functional characteristics of human peritubular cells originating from seminiferous tubule (ST) fragments isolated from the testes of two prepubertal patients with the androgen insensitivity syndrome. These ST were cultured in Dulbecco's Modified Eagle's Medium-Ham's F-12 supplemented with antibiotics, transferrin, hydrocortisone, vitamin E, and 3% fetal bovine serum. A centrifugal growth of elongated fibroblast-like cells peripheral to the ST explants was observed. Muscle-specific actin and 3 beta-hydroxysteroid dehydrogenase were evident in the peritubular area and in the elongated cells growing from the tubules. Histochemistry was negative in the tubules themselves, revealing the mixed nature of these cultures. The ST fragments were lost after subculturing, leaving a homogeneous monolayer of fibroblast-like cells. The steroidogenic potential of these cells was demonstrated by the secretion of testosterone (T) to the culture medium. T secretion was stimulated by hCG in a time-dependent fashion (patient 1: Day 11, 84% and Day 15, 200%; patient 2: Day 8, 73% and Day 11, 32% over basal). FSH also stimulated T secretion (patient 1: Day 5, 136% and Day 8, 89%; patient 2: Day 8, 117% and Day 11, 129% over basal). Furthermore, T secretion by these cultures was 100% higher than that observed in mesenchymal cells obtained from the testicular intertubular space in the same patient. Spontaneous T secretion and hormone responses declined progressively to cease by 25 days in culture. These results suggested the involvement of Sertoli cell (SC)-secreted factor(s) in the regulation of T secretion by peritubular cells. In order to further explore possible paracrine interactions between peritubular and Sertoli cells, we carried out heterologous cocultures with rat SC. After 72 h a striking redistribution of both cell types was observed with the formation of cord-like structures. Ultrastructural examination of these cords showed the formation of a basement membrane between epithelial (Sertoli) and mesenchymal cells of peritubular origin. No resumption of T secretion was observed, but an increase in androgen-binding protein (ABP) production by rat SC under basal (37%) and FSH-stimulated (52%) conditions was evident. Our results show that in the human peritubular compartment, cells exist that can alternatively express steroidogenic functions, associate with SC in a specific mesenchymal-epithelial interaction, and exert regulatory influences on ABP secretion by SC. In addition they indicate that communicating events in the testis are preserved throughout evolution.
Assuntos
Síndrome de Resistência a Andrógenos/patologia , Túbulos Seminíferos/citologia , 3-Hidroxiesteroide Desidrogenases/análise , 3-Hidroxiesteroide Desidrogenases/metabolismo , Actinas/análise , Actinas/metabolismo , Proteína de Ligação a Androgênios/metabolismo , Síndrome de Resistência a Andrógenos/metabolismo , Células Cultivadas , Criança , Gonadotropina Coriônica/farmacologia , Hormônio Foliculoestimulante/farmacologia , Humanos , Masculino , Microscopia Eletrônica , Progesterona/metabolismo , Túbulos Seminíferos/química , Túbulos Seminíferos/metabolismo , Células de Sertoli/citologia , Células de Sertoli/metabolismo , Células de Sertoli/ultraestrutura , Linfócitos T/citologia , Linfócitos T/metabolismo , Linfócitos T/ultraestrutura , Testículo/citologia , Testículo/metabolismo , Testículo/ultraestrutura , Testosterona/metabolismo , Timidina/metabolismo , Fatores de Tempo , TrítioRESUMO
The objective of this study was to describe the maturational changes observed in the seminiferous tubules of the monkey Cebus apella, a New World primate species, from birth to the end of puberty. Nineteen animals were subdivided into four groups: neonatal (1-40 days), infantile (4 months to 1 yr), early pubertal (1 yr, 8 months to 2 yr, 9 months), and late pubertal (4-8 yr). Volumetric determinations of different testicular components were made, tubule diameter and length were calculated, and spermatogenic cells, Sertoli cells, and androgen-binding protein secretion were quantified. Testicular and seminiferous tubule volumes increased significantly in the first 5 months of life and during puberty due to the combined increment in seminiferous tubule diameter and length. The total number of spermatogonia increased until late puberty to stabilize subsequently. Spermatocytes and spermatids appeared during puberty and increased dramatically until the end of this period. The germ cell ratios, indicative of spermatogenic efficiency, improved continuously in late puberty coincidentally with a reduction of spermatocyte degeneration. Sertoli cells proliferated in the neonatal and infantile periods, determining a longitudinal growth of the seminiferous tubules, but remained stable during puberty, when androgen-binding protein secretion increased significantly. The multiplication of germ cells is the main factor responsible for the increment in tubule diameter during puberty and determines the most noticeable postnatal modification of testicular volume. During late puberty, the reduction of spermatocyte degeneration leads to an increment in germ cell ratios and a progressive, but slow, improvement of spermatogenic efficiency, explaining why pubertal development of the testis occurs over such a prolonged period in this primate. This is in contrast to what happens in most laboratory animals and suggests that the Cebus is a useful model for studies of human male puberty.
Assuntos
Envelhecimento/fisiologia , Animais Recém-Nascidos/crescimento & desenvolvimento , Cebus/anatomia & histologia , Cebus/fisiologia , Túbulos Seminíferos/anatomia & histologia , Túbulos Seminíferos/fisiologia , Maturidade Sexual , Testículo/crescimento & desenvolvimento , Proteína de Ligação a Androgênios/metabolismo , Animais , Células Germinativas/citologia , Masculino , Túbulos Seminíferos/citologia , Células de Sertoli/citologiaAssuntos
Gravidez , Adulto , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Androgênios/sangue , Androstenos/metabolismo , Hirsutismo/metabolismo , Proteína de Ligação a Androgênios , Androgênios/metabolismo , Androstano-3,17-diol/sangue , Androstano-3,17-diol/metabolismo , Androstenos/sangue , Desidroepiandrosterona/sangue , Desidroepiandrosterona/metabolismo , Di-Hidrotestosterona/sangue , Di-Hidrotestosterona/metabolismoAssuntos
Gravidez , Adulto , Pessoa de Meia-Idade , Humanos , Masculino , Feminino , Androgênios/sangue , Androstenos/metabolismo , Hirsutismo/metabolismo , Androgênios/metabolismo , Androstenos/sangue , Di-Hidrotestosterona/metabolismo , Di-Hidrotestosterona/sangue , Desidroepiandrosterona/metabolismo , Desidroepiandrosterona/sangue , Proteína de Ligação a Androgênios , Androstano-3,17-diol/metabolismo , Androstano-3,17-diol/sangueRESUMO
Total testicular cells derived from immature and pubertal rats were cultured under long-term conditions. Somatic adherent cells proliferated in culture and produced collagen and proteoglycans. Collagen synthesis accounted for 25% and 5% of total protein synthesized by adherent cells derived from immature, and pubertal rats, respectively. Proteoglycan synthesis was higher in cells from immature than from pubertal rats. The proportion of different types of glycosaminoglycan chains (particularly hyaluronic acid and chondroitin sulphate) also varied according to the age of the donor. The results suggest that the synthesis of extracellular matrix components by somatic testicular cells is an age-related process which probably plays an active role in spermatogenesis.
Assuntos
Matriz Extracelular/metabolismo , Testículo/metabolismo , Envelhecimento/metabolismo , Proteína de Ligação a Androgênios/biossíntese , Animais , Contagem de Células , Células Cultivadas , Colágeno/biossíntese , Masculino , Proteoglicanas/biossíntese , Ratos , Ratos Endogâmicos , Testículo/citologia , Testosterona/biossínteseRESUMO
The adolescent growth spurt in boys is under hormonal control. It is accepted that androgens and growth hormone contribute to male pubertal growth, but the role of estrogens is uncertain even though low-dose estradiol administration stimulates growth in prepubertal boys. In the present work, the correlation of serum testosterone and serum estradiol with growth velocity was studied in 16 pubertal normal boys. The study included correlations of growth velocity with serum nonsex hormone-binding globulin-bound testosterone and with serum nonsex hormone-binding globulin-bound estradiol, which are parameters of serum bioavailable sex hormones. A statistically significant positive correlation was found between serum testosterone and growth velocity but not between serum estradiol and growth velocity. These findings are against the hypothesis that estrogens play a growth promoting role during male puberty.
Assuntos
Estradiol/sangue , Crescimento , Puberdade/sangue , Adolescente , Proteína de Ligação a Androgênios/sangue , Criança , Humanos , Masculino , Puberdade/fisiologia , Globulina de Ligação a Hormônio Sexual/metabolismo , Maturidade Sexual , Testosterona/sangueAssuntos
Separação Celular/métodos , Células Intersticiais do Testículo/análise , Células de Sertoli/análise , Testículo/citologia , Proteína de Ligação a Androgênios/isolamento & purificação , Animais , Fracionamento Celular/métodos , Citosol/análise , Estudos de Avaliação como Assunto , Hormônios Esteroides Gonadais/metabolismo , Masculino , Ratos , Testículo/metabolismoAssuntos
Gravidez , Adolescente , Adulto , Idoso , Animais , Humanos , Proteína de Ligação a Androgênios/fisiologia , Globulina de Ligação a Hormônio Sexual/fisiologia , Albuminas , Neoplasias da Mama/fisiopatologia , Cirrose Hepática/fisiopatologia , Doença da Mama Fibrocística , Hirsutismo/fisiopatologia , Menopausa/fisiologia , Obesidade/fisiopatologia , Gravidez/fisiologia , Globulina de Ligação a Hormônio Sexual/biossíntese , Esteroides/metabolismo , Testosterona/fisiologia , Testosterona/fisiopatologia , TranscortinaAssuntos
Gravidez , Adolescente , Adulto , Idoso , Animais , Humanos , Globulina de Ligação a Hormônio Sexual/fisiologia , Proteína de Ligação a Androgênios/fisiologia , Globulina de Ligação a Hormônio Sexual/biossíntese , Albuminas , Transcortina , Testosterona/fisiopatologia , Testosterona/fisiologia , Neoplasias da Mama/fisiopatologia , Doença da Mama Fibrocística , Cirrose Hepática/fisiopatologia , Menopausa/fisiologia , Gravidez/fisiologia , Hirsutismo/fisiopatologia , Obesidade/fisiopatologia , Esteroides/metabolismoRESUMO
Androgen binding activity (ABP) was determined in two different fractions of developing rat testicular homogenates: in cytosol (cABP) and in a particulate fraction isolated by differential centrifugation (pABP). Homogenates were prepared under stabilization conditions by adding 350 nM testosterone to the homogenization buffer. cABP and pABP concentrations were maximal in 22- to 32-day-old animals, to decrease thereafter during sexual maturation. However, both cABP and pABP increased with age when results were expressed on a per organ basis. pABP could be solubilized under conditions in which it could retain its binding activity. It was then photoaffinity labeled and chromatographed on a Sephadex G 200 column using cytosolic epididymal ABP as a control. Similarities between cABP and pABP include not only the same androgen binding characteristics but also the same exclusion volume after Sephadex G 200 chromatography. Since pABP is only present in Sertoli cells, it might represent ABP before being secreted. Because of its intracellular localization, it could play a role in the compartmentalization of androgens within the testis.
Assuntos
Proteína de Ligação a Androgênios/isolamento & purificação , Maturidade Sexual , Testículo/análise , Animais , Cromatografia em Gel , Citosol/análise , Epididimo/análise , Masculino , Ratos , Ratos EndogâmicosRESUMO
La proteína ligadora de andrógenos (ABP) fue determinada en las fracciones citosólica (cABP) y particulada (pABP), obtenidas por centrifugación diferencial de homogenatos testiculares de ratas. Se prepararon homogenatos en condiciones de estabilización para el ABP por el agregado de testosterona 350 nM al "buffer" de homogeneización. Se observó que tanto los niveles por mg/prot de cABP como de pABP eran máximos entre los 22 y 32 días de edad de la rata, disminuyendo a partir de allí durante la maduración sexual. Cuando los resultados se expresaron por órgano, ambas proteínas aumentaron con la edad del animal. La pABP pudo ser solubilizada en condiciones en que mantuvo su capacidad de unión a andrógenos, procediéndose entonces a su fotomarcación y posterior cromatografía en una columna de Sephadex G-0200, usando el ABP de citosol de epidídimo como control. Se observó que el ABP no sólo comparte con el cABP las mismas características físico-químicas para la unión de andrógenos, sino también el volumen de exclusión en la cromatografía mencionada. Dado que la pABP está solamente presente en la célula de Sertoli, probablemente represente ABP antes de ser secretado. Su localización subcelular sugiere un posible papel del ABP en la distribución de andrógenos testiculares
Assuntos
Ratos , Animais , Masculino , Proteína de Ligação a Androgênios/metabolismo , Citosol/metabolismo , Maturidade Sexual , Testículo/metabolismo , Envelhecimento , Epididimo/metabolismo , Ratos Endogâmicos , Testosterona/metabolismoRESUMO
La proteína ligadora de andrógenos (ABP) fue determinada en las fracciones citosólica (cABP) y particulada (pABP), obtenidas por centrifugación diferencial de homogenatos testiculares de ratas. Se prepararon homogenatos en condiciones de estabilización para el ABP por el agregado de testosterona 350 nM al "buffer" de homogeneización. Se observó que tanto los niveles por mg/prot de cABP como de pABP eran máximos entre los 22 y 32 días de edad de la rata, disminuyendo a partir de allí durante la maduración sexual. Cuando los resultados se expresaron por órgano, ambas proteínas aumentaron con la edad del animal. La pABP pudo ser solubilizada en condiciones en que mantuvo su capacidad de unión a andrógenos, procediéndose entonces a su fotomarcación y posterior cromatografía en una columna de Sephadex G-0200, usando el ABP de citosol de epidídimo como control. Se observó que el ABP no sólo comparte con el cABP las mismas características físico-químicas para la unión de andrógenos, sino también el volumen de exclusión en la cromatografía mencionada. Dado que la pABP está solamente presente en la célula de Sertoli, probablemente represente ABP antes de ser secretado. Su localización subcelular sugiere un posible papel del ABP en la distribución de andrógenos testiculares (AU)
Assuntos
Ratos , Animais , Masculino , Proteína de Ligação a Androgênios/metabolismo , Testículo/metabolismo , Maturidade Sexual , Citosol/metabolismo , Envelhecimento , Epididimo/metabolismo , Testosterona/metabolismo , Ratos EndogâmicosRESUMO
We have studied the acute effect of hOG and testosterone administration to immature rats, on testicular (particulate fraction and cytosol) and epididymal (cytosol) ABP levels. One and four hours after a single dose of 10 IU hCG/rat, ABP concentration decreased slightly in testicular membranes and cytosol, but increased markedly in epididymal cytosol (169 +/- 5 and 182 +/- 5 at 1 and 4 h respectively, compared to 113 +/- 13 fmoles/mg protein in control animals, mean +/- SEM). Since testicular and epididymal concentrations of testosterone increased after hCG, as expected, the effect might have been mediated by gonadotrophin stimulated testosterone production in Leydig cells. To test this hypothesis, the hCG effect was studied in rats that previously had received aminoglutethimide to block steroidogenesis. Under these conditions, hCG failed to increase epididymal ABP. Finally, administration of testosterone propionate was also able to stimulate epididymal ABP, but with delayed response: the increase was observed 4 h after injection (212 +/- 18 compared to 127 +/- 28 fmoles/mg protein in control animals, mean +/- SEM). It is concluded that the hCG-induced increase of intratesticular androgen levels results in rapid passage of ABP from testis to epididymis.
Assuntos
Proteína de Ligação a Androgênios/metabolismo , Gonadotropina Coriônica/farmacologia , Epididimo/metabolismo , Testículo/metabolismo , Testosterona/farmacologia , Animais , Células Intersticiais do Testículo/fisiologia , Masculino , Ratos , Testosterona/metabolismoRESUMO
A method is described for the photoaffinity labeling of human and rabbit serum sex hormone binding globulin (SHBG) in ammonium sulphate precipitates utilizing 3H-delta 6-testosterone as affinity label. The precipitation step diminished albumin contamination and at the same time concentrated the binding globulin. Photolysis was conveniently carried out with an electronic flash. Unbound and non-covalently bound steroids were adsorbed by prolonged dextran-coated charcoal treatment. Sephadex G-200 gel filtration column chromatography showed a single peak of covalently bound radioactivity with the elution volume of SHBG. With some modifications, the method was applied to the affinity labeling of the prostate androgen receptor utilizing 3H-methyltrienolone (R 1881) as affinity label. The receptor was also precipitated from prostate cytosol with ammonium sulphate. After labeling, photolysis and heating at 50 degrees C, non covalently bound 3H-R 1881 was removed by dextran coated charcoal treatment. Sephadex G-25 microcolumn chromatography after heating showed a peak of radioactivity eluting with macromolecules if photolysis had been carried out, while it disappeared in the absence of previous photolysis. However, the photolabeled receptor had a sedimentation coefficient different from the non-irradiated receptor, suggesting that photolysis induced a change in the configuration of the complex.