RESUMO
Testicular aging is linked to histological, morphological and functional alterations. In the present study, we investigated whether aging affects the inflammatory and oxidative status in the testis by comparing young adult, middle-aged adult and aged hamsters. The Syrian hamster, a thoroughly studied seasonal breeder, was chosen as the experimental model since it allows further investigations on the role of photoperiod and melatonin in testicular aging with a minimal impact of the experimental intervention on the animal well-being and the subsequent results achieved. In testes of aged hamsters, we found a decrease in melatonin concentration, a thickening of the wall of the seminiferous tubules as well as a significant increase in IL-1ß, NLRP3 and cyclooxygenase 2 expression, PGD2 production, macrophages numbers, lipid peroxidation and anti-oxidant enzyme catalase levels. Interestingly, when aged hamsters were transferred from a long day (LD) to a short day (SD) photoperiod for 16â¯weeks, testicular melatonin concentration increased while local inflammatory processes and oxidative stress were clearly reduced. Overall, these results indicate that melatonin might display anti-inflammatory and anti-oxidant capacities in the aged testes.
Assuntos
Envelhecimento/fisiologia , Melatonina/fisiologia , Estresse Oxidativo , Fotoperíodo , Testículo/patologia , Animais , Cricetinae , Masculino , MesocricetusRESUMO
Ageing is usually characterised by a mild chronic proinflammatory state. Despite the tight association between both processes, the phenomenon has recently been termed inflammageing. Inflammation in the male reproductive tract is frequently linked with bacterial or virus infections but also with a broad range of noninfectious processes. Prostatitis, epididymitis and orchitis, among others, can lead to infertility. However, in spite of the inflammation theory of disease, chronic inflammation in male urogenital system does not always cause symptoms. With advancing age, inflammatory processes are commonly observed in the male reproductive tract. Nevertheless, the incidence of inflammation in reproductive organs and ducts varies greatly among elderly men. Inflammageing is considered a predictor of pathogenesis and the development of age-related diseases. This article briefly summarises the current state of knowledge on inflammageing in the male reproductive tract. Yet, the precise aetiology of inflammageing in the male urogenital system, and its potential contribution not only to infertility but most importantly to adverse health outcomes remains almost unknown. Thus, further investigations are required to elucidate the precise cross-links between inflammation and male reproductive senescence, and to establish the impact of anti-inflammatory drug treatments on elder men's general health status.
Assuntos
Envelhecimento/imunologia , Anti-Inflamatórios/uso terapêutico , Doenças dos Genitais Masculinos/imunologia , Genitália Masculina/imunologia , Inflamação/imunologia , Fatores Etários , Envelhecimento/patologia , Doenças dos Genitais Masculinos/tratamento farmacológico , Doenças dos Genitais Masculinos/epidemiologia , Doenças dos Genitais Masculinos/patologia , Genitália Masculina/patologia , Humanos , Incidência , Inflamação/tratamento farmacológico , Inflamação/epidemiologia , Inflamação/patologia , MasculinoRESUMO
Melatonin acting through the hypothalamus and pituitary regulates testicular function. In addition, direct actions of melatonin at the testicular level have been recently suggested. We have described that melatonin inhibits androgen production in hamster Leydig cells via melatonin subtype 1a (mel1a) receptors and the local corticotrophin-releasing hormone (CRH) system. The initial events of the melatonin/CRH signalling pathway have also been established. Melatonin and all components of the melatonergic/CRH system were also detected in Leydig cells of infertile men. This study attempted to search for additional targets of melatonin in the human testis, and to investigate the effects of melatonin on proliferation and the oxidative state in these novel target cells. To this aim, evaluation of human testicular biopsies of patients suffering from hypospermatogenesis or Sertoli cell only syndrome and cell culture studies were performed. Melatonergic receptors were found in macrophages (MACs) and mast cells (MCs) of the human testis. In biopsies of patients suffering idiopathic infertility, melatonin testicular concentrations were negatively correlated with MAC number per mm(2) and TNFα, IL1ß and COX2 expression, but positively correlated with the expression of the anti-oxidant enzymes SOD1, peroxiredoxin 1 and catalase. Melatonin inhibited proliferation and the expression of pro-inflammatory cytokines and cyclooxygenase 2 (COX2) in both the human non-testicular THP-1 MAC cell line and primary cell cultures of hamster testicular MACs. In the human HMC-1 MC line, melatonin increased the expression of anti-oxidant enzymes and decreased reactive oxygen species (ROS) generation. The results reveal new testicular targets of melatonin and describe anti-proliferative and anti-inflammatory effects of this hormone on testicular MACs. Furthermore, melatonin might provide protective effects against oxidative stress in testicular MCs.
Assuntos
Infertilidade Masculina/metabolismo , Macrófagos/metabolismo , Mastócitos/metabolismo , Melatonina/metabolismo , Testículo/metabolismo , Adulto , Androgênios/biossíntese , Animais , Anti-Inflamatórios , Antioxidantes/metabolismo , Azoospermia/metabolismo , Catalase/biossíntese , Linhagem Celular , Proliferação de Células , Hormônio Liberador da Corticotropina/metabolismo , Cricetinae , Ciclo-Oxigenase 2/biossíntese , Humanos , Interleucina-1beta/biossíntese , Células Intersticiais do Testículo/metabolismo , Macrófagos/citologia , Masculino , Mastócitos/citologia , Oligospermia/metabolismo , Estresse Oxidativo , Peroxirredoxinas/biossíntese , Espécies Reativas de Oxigênio/análise , Receptores de Melatonina/antagonistas & inibidores , Receptores de Melatonina/metabolismo , Síndrome de Células de Sertoli/metabolismo , Transdução de Sinais , Superóxido Dismutase/biossíntese , Superóxido Dismutase-1 , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Transforming growth factor ß1 (TGF-ß1) is a pleiotropic cytokine that modulates cell homeostasis. In Leydig cells, TGF-ß1 exerts stimulatory and inhibitory effect depending on the type I receptor involved in the signaling pathway. The aim of the present work was to study the signaling mechanisms and the intermediates involved in the action of TGF-ß1 on TM3 Leydig cell proliferation in the presence or absence of progesterone. The MTT assay showed that the presence of progesterone in the culture media lead to a proliferative effect that was blocked by Ru 486, an inhibitor of progesterone receptor; and ALK-5 did not participate in this effect. TGF-ß1 (1 ng/ml) increased the expression of p15 (an inhibitor of cell cycle) in TM3 Leydig cells, and this effect was blocked by progesterone (1µM). The expression of PCNA presented a higher increase in the cell cultured with TGF-ß1 plus progesterone than in cells cultured only with TGF-ß1. Progesterone induced the gene expression of endoglin, a cofactor of TGF-ß1 receptor that leads to a stimulatory signaling pathway, despite of the absence of progesterone response element in endoglin gene. In addition, the presence of progesterone induced the gene expression of egr-1 and also KLF14, indicating that this steroid channels the signaling pathway into a non-canonical mechanism. In conclusion, these findings suggest that the proliferative action of TGF-ß1 involves endoglin. This co-receptor might be induced by KLF14 which is probably activated by progesterone.
Assuntos
Proteína 1 de Resposta de Crescimento Precoce/metabolismo , Fatores de Transcrição Kruppel-Like/metabolismo , Células Intersticiais do Testículo/citologia , Células Intersticiais do Testículo/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Receptores de Ativinas Tipo I/genética , Receptores de Ativinas Tipo I/metabolismo , Receptores de Activinas Tipo II , Animais , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p15/metabolismo , DNA Complementar/genética , Endoglina , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Células Intersticiais do Testículo/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Progesterona/farmacologia , Antígeno Nuclear de Célula em Proliferação/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Receptor do Fator de Crescimento Transformador beta Tipo I , Receptor do Fator de Crescimento Transformador beta Tipo II , Receptores de Fatores de Crescimento Transformadores beta/genética , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Elementos de Resposta/genética , Fatores de Transcrição/metabolismo , Fator de Crescimento Transformador beta1/genética , Fator de Crescimento Transformador beta1/farmacologiaRESUMO
In Leydig cells, hormonal stimulation by LH/hCG entails increased intracellular Ca(2+) levels and steroid production, as well as hyperpolarization of the cell membrane. The large-conductance Ca(2+)-activated K(+)-channel (BK(Ca)) is activated by raised intracellular Ca(2+) and voltage and typically hyperpolarizes the cell membrane. Whether BK(Ca) is functionally involved in steroid production of Leydig cells is not known. In order to explore this point we first investigated the localization of BK(Ca) in human and hamster testes and then used a highly specific toxin, the BK(Ca) blocker iberiotoxin (IbTx), to experimentally dissect a role of BK(Ca). Immunohistochemistry and RT-PCR revealed that adult Leydig cells of both species are endowed with these channels. Ontogeny studies in hamsters indicated that BK(Ca) becomes strongly detectable in Leydig cells only after they acquire the ability to produce androgens. Using purified Leydig cells from adult hamsters, membrane potential changes in response to hCG were monitored. HCG hyperpolarized the cell membrane, which was prevented by the selective BK(Ca) blocker IbTx. Steroidogenic acute regulatory (StAR) mRNA expression and testosterone production were not affected by IbTx under basal conditions but markedly increased when hCG, in submaximal and maximal concentration or when db-cAMP was added to the incubation media. A blocker of K(V)4-channels, expressed by Leydig cells, namely phrixotoxin-2 (PhTx-2) was not effective. In summary, the data reveal BK(Ca) as a crucial part of the signaling cascade of LH/hCG in Leydig cells. The hyperpolarizing effect of BK(Ca) in the Leydig cell membrane appears to set in motion events limiting the production of testosterone evoked by stimulatory endocrine mechanisms.
Assuntos
Gonadotropina Coriônica/metabolismo , Subunidades alfa do Canal de Potássio Ativado por Cálcio de Condutância Alta/metabolismo , Células Intersticiais do Testículo/metabolismo , Hormônio Luteinizante/metabolismo , Transdução de Sinais , Animais , Cricetinae , Fluorescência , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Células Intersticiais do Testículo/citologia , Células Intersticiais do Testículo/efeitos dos fármacos , Masculino , Potenciais da Membrana/efeitos dos fármacos , Mesocricetus , Peptídeos/farmacologia , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Transdução de Sinais/efeitos dos fármacos , Testosterona/biossínteseRESUMO
Sialic acid content in FSH is modulated by GnRH and sexual steroids. Galbeta1,3GlcNAcalpha2,3-sialyltransferase (ST3Gal III) and Galbeta1,4GlcNAcalpha2,6-sialyltransferase (ST6Gal I) incorporate sialic acid residues into FSH oligosaccharides. The aim of the present study was to assess pituitary FSH molecular microheterogeneity and ST3Gal III/ST6Gal I expression during sexual development and after castration in male rats. Preparative isoelectric focusing and lectin chromatography were used to isolate FSH glycosylation variants according to charge and complexity of their oligosaccharides; RT-PCR and immunohistochemistry were employed to analyse sialyltransferase expression. Sexual development was associated with a progressive shift towards more acidic/sialylated FSH glycoforms concomitantly with an increment in ST6Gal I gene and protein expression. After castration, a transient decrease followed by a marked increase in ST6Gal I expression were observed. Less acidic/sialylated FSH glycoforms bearing incomplete oligosaccharides increased after castration, despite high ST6Gal I expression. ST3Gal III expression remained unchanged in all the experimental conditions examined. These results show that the synthesis of FSH isoforms possessing alpha2,6-linked sialic acid is hormonally regulated in male rats.
Assuntos
Hormônio Foliculoestimulante/metabolismo , Ácido N-Acetilneuramínico/metabolismo , Hipófise/metabolismo , Envelhecimento/metabolismo , Animais , Castração , Cromatografia , Concanavalina A/metabolismo , Hormônio Foliculoestimulante/sangue , Regulação Enzimológica da Expressão Gênica , Gonadotrofos/citologia , Gonadotrofos/metabolismo , Imuno-Histoquímica , Focalização Isoelétrica , Masculino , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Desenvolvimento Sexual , Sialiltransferases/genética , Sialiltransferases/metabolismo , Testosterona/sangue , beta-D-Galactosídeo alfa 2-6-Sialiltransferase , beta-Galactosídeo alfa-2,3-SialiltransferaseRESUMO
There are few data for hormonal levels and testis structure and function during postnatal development in rats neonatally treated with monosodium L-glutamate (MSG). In our study, newborn male pups were ip injected with MSG (4 mg/g body weight) every 2 d up to 10 d of age and investigated at prepubertal and adult ages. Plasma levels of leptin, LH, FSH, prolactin, testosterone (T), corticosterone, and free T4 (FT4) were measured. MSG rats displayed elevated circulating levels of corticosterone and hyperadiposity/hyperleptinemia, regardless of the age examined; conversely, circulating prolactin levels were not affected. Moreover, prepubertal MSG rats revealed a significant (P < 0.05) reduction in testis weight and the number of Sertoli (SC) and Leydig cells per testis. Leptin plasma levels were severalfold higher (2.41 vs. 8.07; P < 0.05) in prepubertal MSG rats, and these animals displayed plasma LH, FSH, T, and FT4 levels significantly decreased (P < 0.05). Taken together, these data indicate that testis development, as well as SC and Leydig cell proliferation, were disturbed in prepubertal MSG rats. Adult MSG rats also displayed significantly higher leptin plasma levels (7.26 vs. 27.04; P < 0.05) and lower (P < 0.05) LH and FSH plasma levels. However, T and FT4 plasma levels were normal, and no apparent alterations were observed in testis structure of MSG rats. Only the number of SCs per testis was significantly (P < 0.05) reduced in the adult MSG rats. In conclusion, although early installed hyperadipose/hyperleptinemia phenotype was probably responsible for the reproductive axis damages in MSG animals, it remains to be investigated whether this condition is the main factor for hypothalamus-pituitary-gonadal axis dysfunction in MSG rats.
Assuntos
Tecido Adiposo/metabolismo , Testículo/patologia , Animais , Animais Recém-Nascidos , Núcleo Celular/metabolismo , Proliferação de Células , Corticosterona/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Leptina/metabolismo , Células Intersticiais do Testículo/metabolismo , Masculino , Camundongos , Fenótipo , Prolactina/sangue , Ratos , Ratos Sprague-Dawley , Túbulos Seminíferos/metabolismo , Túbulos Seminíferos/patologia , Células de Sertoli/metabolismo , Testículo/metabolismo , Testosterona/sangue , Tiroxina/sangue , Fatores de TempoRESUMO
The aim of the present study was to establish the serum levels of inhibins and their relationship with the degree of seminal alteration in infertile men. Thirty-six patients with varicocele (Va) and seven non-obstructive azoospermic men (Az) were included. The Va group was divided into two subgroups: Va I (sperm concentration: >20 x 106; n = 21) and Va II (sperm concentration: < 20 x 106; n = 15). Twelve fertile men were included as a control group (Co). Semen analysis and serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), inhibin B and Pro-alphaC levels were determined. Serum inhibin B and T levels were significantly lower and FSH and LH significantly higher in group Az when compared with the Co. Inhibin B was unable to differentiate Va I from Va II groups. However, in Va II an increase in FSH levels was observed. An inverse correlation between inhibin B and FSH, a direct correlation between inhibin B and testosterone, sperm concentration, motility and morphology were found. No such correlations were seen when only the Va group was analysed. The lack of correlation between serum levels of inhibin B, gonadotrophins, sperm concentration and seminal parameters observed in Va, adds other factor to the complex pathophysiology of varicocele. Finally, further studies are needed to elucidate if oligozoospermic patients with varicocele have also an impaired negative feed-back mechanism that regulates FSH synthesis and secretion.
Assuntos
Biomarcadores/sangue , Infertilidade Masculina/sangue , Inibinas/sangue , Varicocele/sangue , Adulto , Hormônio Foliculoestimulante/sangue , Humanos , Infertilidade Masculina/etiologia , Hormônio Luteinizante/sangue , Masculino , Pessoa de Meia-Idade , Oligospermia/sangue , Valores de Referência , Sêmen/química , Sêmen/citologia , Contagem de Espermatozoides , Testosterona/sangue , Varicocele/complicaçõesRESUMO
Polyamines are involved in cellular growth and differentiation. To analyze a possible role of polyamines on the regulation of Sertoli cell function, we studied the effect of putrescine, spermidine, and spermine on gamma-glutamyl transpeptidase (gamma-GTP) activity and lactate production on Sertoli cell cultures obtained from immature and adult-regressed golden hamsters. Sertoli cells were cultured for 7 days. The 72 hour conditioned media obtained on day 6 were used to evaluate lactate levels. Gamma glutamyl transpeptidase activity was determined in the cells harvested on day 7. Cultured Sertoli cells isolated from immature and adult-regressed golden hamsters exhibited a clear morphological response to follicle-stimulating hormone (FSH) and to spermine. Gamma glutamyl transpeptidase activity increased in response to FSH in a dose-dependent manner. Dose-dependent stimulation of lactate production by FSH was also observed. For each functional parameter, a similar ED50 value of FSH stimulation was observed in both groups of animals. Spermine increased basal and FSH-stimulated gamma-GTP activity in immature and adult-regressed Sertoli cell cultures. A stimulatory effect of spermidine and putrescine on gamma-GTP activity was exclusively observed in adult-regressed Sertoli cell cultures. In Sertoli cells obtained from immature hamsters, spermine exerted a stimulatory effect on basal and FSH-stimulated lactate production. These results suggest that, in addition to the known effects of hormones and paracrine factors, polyamines may influence the functionality of Sertoli cells.
Assuntos
Cricetinae/fisiologia , Ácido Láctico/biossíntese , Putrescina/farmacologia , Células de Sertoli/metabolismo , Espermidina/farmacologia , Espermina/farmacologia , gama-Glutamiltransferase/metabolismo , Envelhecimento/fisiologia , Animais , Células Cultivadas , Hormônio Foliculoestimulante/farmacologia , Masculino , Fotoperíodo , Reprodução/efeitos da radiação , Células de Sertoli/citologiaRESUMO
The presence and characteristics of androgen receptors (ARs) have been described by our group in one human melanoma cell line. We have now investigated their presence in two other human melanoma cell lines, IIB-MEL-LES and IIB-MEL-IAN, as well as in biopsies from human metastatic melanoma. Scatchard analysis revealed a single binding component for both cell lines, the apparent dissociation constant obtained being 15 nM, with a binding capacity of 280 fmol/mg total cell protein, for IIB-MEL-LES cells and 14 nM, with a binding capacity of 206 fmol/mg total cell protein for IIB-MEL-IAN cells. When specificity was assessed, not only androgen and anti-androgen but also non-androgenic compounds were able to compete for [3H]R1881 binding, as seen before. When immunocytochemistry of IIB-MEL-LES and IIB-MEL-IAN cells was performed for ARs, both cell lines were deeply stained in the nucleus, whereas no staining was found for oestrogen or progesterone receptors. Every specimen of melanoma metastases tested for the presence of ARs was deeply stained, and in the majority the intensity of the staining was high. Several hormones and anti-hormones were tested for their ability to affect cell proliferation. In both cell lines, testosterone, dihydrotesterone, oestradiol and progesterone significantly stimulated cell proliferation, and this was reversed by hydroxyflutamide, bicalutamide or tamoxifen.
Assuntos
Hormônios/fisiologia , Melanoma/metabolismo , Melanoma/secundário , Receptores Androgênicos/metabolismo , Adulto , Ligação Competitiva , Biópsia , Divisão Celular/efeitos dos fármacos , Divisão Celular/fisiologia , Interpretação Estatística de Dados , Di-Hidrotestosterona/farmacologia , Feminino , Hormônios/farmacologia , Humanos , Imuno-Histoquímica , Masculino , Melanoma/patologia , Melanoma Amelanótico/metabolismo , Melanoma Amelanótico/patologia , Melanoma Amelanótico/secundário , Receptores de Esteroides/metabolismo , Células Tumorais CultivadasRESUMO
The aim of the present study was to evaluate inhibin secretion in rats with autoimmune orchitis. As we have previously described, experimental autoimmune orchitis (EAO) induced in rats by active immunization with testis homogenate and adjuvants is characterized by an interstitial mononuclear cell infiltrate and sloughing of the germinal epithelium. At 120 days after the first immunization 60% of the rats exhibited a severe orchitis with large areas of aspermatogenic seminiferous tubules in which only spermatogonia and Sertoli cells with cytoplasmic vacuolization remained attached to the tubular wall. None of the untreated (N) or control (C) rats revealed pathological alterations. Sixty percent decrease in testis weight was observed in rats with EAO compared with N or C groups. A 3-fold increase in serum FSH levels was observed in rats with EAO compared with N or C groups (19.8+/-3.7 vs 5.6+/-0.3 and 5.9+/-0.1 ng/ml respectively). A significant decrease in inhibin B levels was observed in rats with EAO when compared with N or C groups (40+/-4.6 vs 207+/-38.8 and 221.4+/-28.6 pg/ml respectively). An inverse correlation between inhibin B and FSH serum levels and a direct correlation between inhibin B and testis weight were found. Strong expression of the inhibin alpha-subunit in Sertoli cells of untreated and control rats was observed; this subunit was undetectable or poorly detectable in rats with orchitis. Positive staining for the inhibin alpha-subunit was also observed in Leydig cells of all groups studied. In conclusion, using a model of autoimmune orchitis our results show that circulating inhibin B levels and inhibin alpha-subunit expression in Sertoli cell cytoplasm closely correlate with the degree of damage of the germinal epithelium.
Assuntos
Doenças Autoimunes/fisiopatologia , Inibinas/metabolismo , Orquite/fisiopatologia , Túbulos Seminíferos/patologia , Análise de Variância , Animais , Doenças Autoimunes/sangue , Doenças Autoimunes/patologia , Hormônio Foliculoestimulante/sangue , Imuno-Histoquímica , Inibinas/sangue , Hormônio Luteinizante/sangue , Masculino , Modelos Animais , Orquite/sangue , Orquite/patologia , Tamanho do Órgão , Ratos , Ratos Sprague-Dawley , Células de Sertoli/química , Testículo/patologiaRESUMO
Specific blockade of the androgen receptor by the nonsteroid antiandrogens flutamide and Casodex has proven to be a useful tool for studying androgens in vivo. The aim of the present study was to investigate the effect of antiandrogen administration at the pituitary level by evaluating the ultrastructural changes in gonadotrophs, in correlation with the quantitative immunohistochemical findings, and by comparing these alterations with the effect of androgen deprivation by castration either with or without subsequent androgen replacement. Male Sprague-Dawley rats (23 days old) were grouped as follows: (1) controls, (2) flutamide-injected (10 mg/rat/day), (3) Casodex-injected (10 mg/rat/day), (4) castrated, and (5) castrated plus androgen-replaced (dihydrotestosterone propionate; 40 microg/rat/day). Groups were sacrificed after 10 days of maintenance under each condition. Pituitaries were processed for both light and electron microscopy. Serial sections (4 microm) were obtained at different levels and immunostained by means of the primary murine monoclonal antibodies anti-FSH and anti-LH and a peroxidase-mediated EnVision System (Dako). Volume density, cell density and mean cell area were measured with an image analysis system (Imaging Technology, Software Optimas 5.2). The mean cell area (p < 0.001) and the volume density (p < 0.05) increased significantly in the flutamide- and Casodex-treated groups as well as the castrated group of FSH and LH cells. On the other hand, androgen replacement in the castrated rats, however, reduced in both parameters related to control animals. The cell density of FSH-secreting cells was increased (p < 0.05) in the Casodex and flutamide treatment as well as castrated group. The cell density of LH-secreting cells was augmented (p < 0.05) in the Casodex-treated group, while there was no increase in such parameter with flutamide and castration. The ultrastructure of all groups showed two types of gonadotrophs. Type I cells contained large (300-500 nm) and small (150-200 nm) secretory granules, while type II cells were smaller, and exhibited only small granules (100-200 nm). Flutamide-treated, Casodex-treated and castrated groups presented a decreased number of secretory granules with some exocytotic profiles, well-developed rough endoplasmic reticulum and an expanded Golgi complex of both types of cells. The gonadotrophs from the castrated group exhibited numerous mitochondria with electron-dense ring-shaped laminar figures, while in the castrated plus androgen-replaced rats only a few mitochondria had similar changes to those observed in castrated animals, as a possible residual alteration. Finally, the gonadotrophs from flutamide-treated rats showed mitochondrial alterations with clear areas and isolated electron-dense laminar figures. In summary, we conclude that lack of androgen reaction through the effects of nonsteroid antiandrogens and castration on prepubertal rats produced a hypertrophia-hyperplasia of the FSH cells, and hypertrophia of LH-secreting cells, with marked alterations at the ultrastructural level suggestive of a hyperstimulation stage.
Assuntos
Antagonistas de Androgênios/farmacologia , Anilidas/farmacologia , Flutamida/farmacologia , Adeno-Hipófise/efeitos dos fármacos , Animais , Di-Hidrotestosterona/uso terapêutico , Hormônio Foliculoestimulante/metabolismo , Terapia de Reposição Hormonal , Imuno-Histoquímica , Hormônio Luteinizante/metabolismo , Masculino , Microscopia Eletrônica , Nitrilas , Adeno-Hipófise/metabolismo , Adeno-Hipófise/ultraestrutura , Ratos , Ratos Sprague-Dawley , Vesículas Secretórias/efeitos dos fármacos , Vesículas Secretórias/ultraestrutura , Maturidade Sexual , Compostos de TosilRESUMO
PROBLEM: The aim of this study was to investigate the influence of immune-activated testicular macrophages obtained from rats with autoimmune orchitis (EAO) on Leydig cell steroidogenesis. METHOD OF STUDY: EAO was induced in rats by active immunization with testis homogenate and adjuvants. Testicular and peritoneal macrophages from rats with EAO were isolated and cultured for 24 hr. Testosterone (T) production by purified Leydig cells incubated in vitro with macrophage-conditioned media (CM) from rats with EAO or control rats was measured. RESULTS: An increase in T production by Leydig cells incubated with CM from testicular, but not peritoneal, macrophages of rats with EAO was observed. This increase was dose-dependent up to a concentration of 30% CM; proportions higher than 35% exhibited an inhibitory effect. CONCLUSIONS: Immune-activated testicular macrophages obtained from rats with EAO induced both stimulatory and inhibiting steroidogenic effects on Leydig cells in vitro and not the exclusively inhibitory action that has widely been attributed to activated macrophages. This dual effect probably depends on the ability of these cells to synthesize different molecules that may exert opposite effects.
Assuntos
Doenças Autoimunes/imunologia , Meios de Cultivo Condicionados/farmacologia , Células Intersticiais do Testículo/imunologia , Macrófagos/imunologia , Orquite/imunologia , Testículo/imunologia , Animais , Células Cultivadas , Gonadotropina Coriônica/farmacologia , Meios de Cultivo Condicionados/química , Relação Dose-Resposta Imunológica , Células Intersticiais do Testículo/efeitos dos fármacos , Células Intersticiais do Testículo/metabolismo , Macrófagos/metabolismo , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Testosterona/antagonistas & inibidores , Testosterona/biossínteseRESUMO
Follicle-stimulating hormone (FSH) is involved in the regulation and maintenance of gametogenesis. It exists in multiple molecular forms with different oligosaccharide structures which in turn are influenced by the hormonal milieu. Previous studies from our laboratory demonstrated that antiandrogen administration to immature male rats altered the biological activity and the distribution profile of pituitary FSH isoforms. The aim of this study was to examine possible modifications in pituitary FSH polymorphism throughout sexual development (10-, 32- and 75-day-old rats). In addition, the effect of androgen deprivation by castration (32-day-old rats) and its replacement with a nonaromatizable androgen - dihydrotestosterone - on pituitary FSH polymorphism was determined. Concanavalin A affinity chromatography was used to isolate groups of FSH isoforms according to their carbohydrate inner structure. Radioimmunoassay and Sertoli cell bioassay were used to evaluate FSH immuno- and bioactivities. Androgen rise in serum was accompanied by a marked increase in pituitary bio- and immuno-FSH content in 32- and 75-day-old rats. However, FSH pituitary content did not vary despite the significant increment observed in serum FSH levels after castration and decrease to control levels after androgen replacement. The distribution profile of immuno- and bioactive FSH changed throughout sexual maturation. The proportion of pituitary FSH isoforms bearing complex oligosaccharide structures (triantennary, bisecting, complete and truncated biantennary) increased with age, with a concomitant decrease in the proportion of isoforms bearing incomplete carbohydrate chains. The distribution profile observed in castrated 32-day-old rats was similar to that determined in 10-day-old animals. Androgen replacement restored the distribution profile to normal. These results suggest that androgens regulate the incorporation of sugar residues to the carbohydrate chains of pituitary FSH favoring the biosynthesis of complex-type oligosaccharide structures.
Assuntos
Di-Hidrotestosterona/sangue , Hormônio Foliculoestimulante/sangue , Hipófise/imunologia , Hipófise/metabolismo , Animais , Di-Hidrotestosterona/farmacologia , Hormônio Foliculoestimulante/química , Isomerismo , Masculino , Oligossacarídeos/química , Orquiectomia , Hipófise/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Maturidade Sexual/fisiologia , Testosterona/sangueRESUMO
In the male rat, androgens are involved in the feedback regulation of gonadotropin synthesis and secretion. Specific androgen-receptor blockade by the nonsteroidal antiandrogens, flutamide and Casodex, has proven to be a valid tool for studying androgen effects in vivo. The aim of the present study was to investigate the effect of antiandrogen administration at the pituitary level by evaluating the changes in gonadotropes through quantitative immunohistochemistry, and by comparing these alterations with the effect of androgen deprivation by castration either with or without subsequent androgen replacement. Male Sprague-Dawley rats (23 days old) were randomly divided into 5 groups for the following treatments: (a) controls; (b) flutamide-injected (10 mg/rat/day in a gelatin vehicle); (c) Casodex-injected (10 mg/rat/day in an oil vehicle); (d) castrated, and (e) castrated and dihydrotestosterone propionate-replaced (40 microg/rat/day in an oil vehicle). Groups were then sacrificed after 10 days of maintenance under each condition. Pituitaries were fixed in Bouin's fluid and embedded in paraffin. Serial sections (4 micrometer) were obtained at different levels and immunostained by means of the primary murine monoclonal antibodies anti-FSH and anti-LH and a peroxidase-mediated EnVision System (Dako). Measurements of volume density (VD) and individual mean cell area were made by means of an image-analysis system (Imaging Technology, Optimas). Serum FSH and LH levels were determined by radioimmunoassay (RIA). Serum gonadotropin levels, VD, and mean cell area increased significantly in the flutamide-treated, Casodex-treated, and castrated groups (p < 0.05). Androgen replacement in the castrated rats, however, reduced VD, mean cell area, and serum gonadotropins to levels comparable to those of controls. We conclude that either androgen blockade by antiandrogens or castration produce an enhancement in the gonadotrope cell population in prepubertal rats, as shown by an increase in both VD and mean cell area, as well as an elevation in FSH- and LH-immunoreactive cells. These observations correlate well with the changes found in the levels of circulating gonadotropins as measured by RIA.
Assuntos
Antagonistas de Androgênios/farmacologia , Anilidas/farmacologia , Di-Hidrotestosterona/análogos & derivados , Hipófise/química , Maturidade Sexual , Animais , Di-Hidrotestosterona/sangue , Di-Hidrotestosterona/farmacologia , Flutamida/farmacologia , Hormônio Foliculoestimulante/análise , Hormônio Foliculoestimulante/sangue , Imuno-Histoquímica , Hormônio Luteinizante/análise , Hormônio Luteinizante/sangue , Masculino , Nitrilas , Orquiectomia , Hipófise/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Compostos de TosilRESUMO
The golden (Syrian) hamster is a seasonal breeder, and exposure of adult animals to short days results in severe gonadal regression with morphological features that resemble the immature testis. The purpose of this study was to investigate testicular steroidogenic capacity in the golden hamster and to analyse the influence of age and photoperiod on this process. Hamsters aged 36 days were maintained on a long photoperiod (14L:10D), and adult animals were then exposed to a long or a short photoperiod (6L:18D) for 14 weeks (the period of time required to achieve maximal gonadal regression), to assess circulating levels and in vitro production of testosterone, dihydrotestosterone and androstane-3 alpha, 17 beta-diol. In peripubertal hamsters, androstane-3 alpha, 17 beta-diol was the main circulating androgen detected, whereas in active adult animals, testosterone showed the highest serum levels. In hamsters exposed to a short photoperiod, blood testosterone levels were significantly lower than levels in adult hamsters exposed to a long photoperiod. Exposure of adult hamsters to a short photoperiod produced a marked reduction in serum concentrations of dihydrotestosterone and androstane-3 alpha, 17 beta-diol, which was not accompanied by a decrease in testicular 5 alpha-reductase activity. In the in vitro experiments, active adult testes were less sensitive than inactive adult testes to stimulation of androgen production with hCG, but showed similar sensitivity to the gonads from hamsters aged 36 days. In accordance with circulating androgen concentrations, the principal androgens produced in the in vitro assays from peripubertal and normal adult testes were androstane-3 alpha, 17 beta-diol and testosterone, respectively. Unexpectedly, the main androgen produced from regressed testes under in vitro conditions was androstane-3 alpha, 17 beta-diol. Inactive gonads released more androstane-3 alpha, 17 beta-diol than did normal adult testes and total in vitro androgen production (testosterone + dihydrotestosterone + androstane-3 alpha, 17 beta-diol) from adult testes was not diminished by exposure to a short photoperiod. However, in spite of the significant increase detected in production of androstane-3 alpha, 17 beta-diol in vitro from regressed testes, inactive gonads produced less androstane-3 alpha, 17 beta-diol than did peripubertal testes. In summary, our studies suggest that testicular androgen biosynthetic capacity in adult hamsters exposed to short photoperiod is not reduced and these regressed testes represent an intermediate physiological state between peripubertal and active adult testes. The significant decrease detected in serum androgen concentrations during the involution phase could result from the absence of stimulating pituitary factors, together with a negative regulation of steroidogenesis by different non-steroidal signals originating within and/or outside of the testis.
Assuntos
Envelhecimento/fisiologia , Androgênios/biossíntese , Fotoperíodo , Esteroides/biossíntese , Testículo/fisiologia , 3-Oxo-5-alfa-Esteroide 4-Desidrogenase/metabolismo , Androgênios/sangue , Androstano-3,17-diol/metabolismo , Animais , Peso Corporal , Gonadotropina Coriônica/farmacologia , Cricetinae , Di-Hidrotestosterona/metabolismo , Técnicas In Vitro , Masculino , Mesocricetus , Tamanho do Órgão , Maturidade Sexual , Testículo/efeitos dos fármacos , Testículo/enzimologia , Testosterona/biossínteseRESUMO
Serotonin (5-HT) is found in the gonads and accessory reproductive organs of several species. The golden (Syrian) hamster is a seasonal breeder. Exposure of male adult hamsters to short days for 14 weeks results in a severe gonadal regression, while after a photoinhibition period of 22 weeks a spontaneous testicular recrudescence occurs. The aim of this study was to investigate the presence of 5-HT and its major metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the gonads of golden hamsters, its immunolocation and its physiological role in the testis. The influence of age and photoperiod was also analyzed. Hamsters of 23, 36, 46, 60 and 90 days of age were kept in long photoperiod (LP: 14:10 h light/dark), and adult animals were exposed either to LP or to short photoperiod (SP: 6:18 h light/dark) for 14 and 22 weeks. Testicular parenchyma and capsule levels of 5-HT and 5-HIAA increased significantly at ages of 36 and 60-90 days, but decreased markedly during the exposure of adult hamsters to SP for 14 and 22 weeks. Mast cells were found exclusively in the testicular capsule. The testicular number of mast cells increased concomitantly with age, but decreased in adult hamsters exposed to SP. Mast and Leydig cells presented 5-HT-positive immunoreactivity. During sexual maturation as well as during the transfer of adult hamsters from LP to SP, the 5-HIAA/5-HT ratio showed the highest values in active adult animals, indicating that the increase in testicular 5-HT levels in adulthood is accompanied by an augment in 5-HT turnover. In vitro basal and hCG-stimulated testosterone production was significantly inhibited in presence of physiological concentrations of 5-HT. In conclusion, the present studies demonstrate the existence of 5-HT in mast cells and Leydig cells of hamster testes, as well as describe an inhibitory action of this neurotransmitter on gonadal testosterone production. Furthermore, the age-dependent and photoperiodic-related changes detected in testicular 5-HT levels suggest that this neurotransmitter might act as an important local modulator of the action of gonadotropins on steroidogenesis during sexual development and during the photoperiodic regression-recrudescence transition in the golden hamster.