RESUMO
Circulating TFH (cTFH ) cells express CXCR5, PD-1, and, when activated, ICOS, and release IL-21. According to the production of IFN-γ, IL-4, and IL-17 and expression of FoxP3, these cells are also classified as cTFH 1, cTFH 2, cTFH 17, and cTFR cells, respectively. This CD4+ T-cell subset is pivotal to efficient humoral immunity, and pregnancy appears to favor IgG production. Here, not only pregnancy amplified the in vivo production of anti-HBsAg IgG in HBV immunized women, but the frequency of cTFH cells was directly correlated with estradiol levels. In vitro, pregnancy-related dose of 17-ß-estradiol (E2) directly increased the percentage of different cTFH subsets. While E2 and progesterone (P4) increased the proportion of differentiated TFH cells derived from naïve CD4+ T-cells, only E2 amplified the release of IL-21 in those cell cultures. In addition, E2 and P4 increased the proportion of memory B cells and plasma cells, respectively. In SEB-activated B/TFH cell co-cultures, E2, in the presence of P4, increased the production of total IgG. Finally, among the hormones, P4 was stronger in upregulating the percentage of IL-10+ TFR cells. Collectively, our findings suggested that E2 and P4 cooperate in the humoral immune response by favoring the expansion of different cTFH and B cell subsets.
Assuntos
Linfócitos B/imunologia , Estradiol/sangue , Estradiol/imunologia , Imunidade Humoral , Gravidez/sangue , Gravidez/imunologia , Progesterona/sangue , Progesterona/imunologia , Células T Auxiliares Foliculares/imunologia , Adulto , Subpopulações de Linfócitos B/efeitos dos fármacos , Subpopulações de Linfócitos B/imunologia , Diferenciação Celular , Citocinas/metabolismo , Estradiol/farmacologia , Feminino , Vacinas contra Hepatite B/imunologia , Humanos , Imunoglobulina G/biossíntese , Técnicas In Vitro , Interleucinas/biossíntese , Progesterona/farmacologia , Células T Auxiliares Foliculares/classificação , Células T Auxiliares Foliculares/citologia , Adulto JovemRESUMO
OBJECTIVE: To evaluate whether progesterone (P4) is able to modulate the secretion of tumour necrosis factor α (TNF-α), interleukin-1ß (IL-1ß), IL-6, IL-8, IL-10 and matrix metalloproteinase-9 (MMP-9) after choriodecidual stimulation with lipopolysaccharide (LPS). DESIGN: Chorioamnionitis-elicited preterm delivery is associated with an uncontrolled secretion of proinflammatory cytokines that may induce MMPs, which modify the fine immunological and structural equilibrium at the fetal-maternal interface. SETTING: Instituto Nacional de Perinatología 'Isidro Espinosa de los Reyes', Mexico City. SAMPLE: Twelve human fetal membranes at term from healthy patients were placed in a two-chamber culture system. METHODS: Choriodecidual and amniotic regions were preincubated with 1.0, 0.1, or 0.01 µmol/l P4 for 24 hours; after which the choriodecidual region was costimulated with 1000 ng/ml of LPS for 24 hours. MAIN OUTCOME MEASURES: Descriptive statistics were obtained for each variable. Data distribution was tested for normality using Kolmogorov-Smirnoff and Shapiro-Wilk tests. When distribution was normal, Student's t test was used to analyse for differences among groups. Mann-Whitney's U test was used when data were not normally distributed. RESULTS: Pretreatment with 1.0 µmol/l P4 significantly blunted the secretion of TNF-α, IL-1ß, IL-6, IL-8 and IL-10. MMP-9 was inhibited with 0.1 µmol/l P4. Mifepristone (RU486) blocked the immunosuppressive effect of P4, suggesting a P4 effect mediated by its receptor. CONCLUSION: These results offer evidence to support the concept that P4 can protect the fetal-placental unit through a compensatory mechanism that partially limits the secretion of proinflammatory and prodegradative modulators.
Assuntos
Citocinas , Decídua/efeitos dos fármacos , Membranas Extraembrionárias/efeitos dos fármacos , Progesterona/farmacologia , Progestinas/farmacologia , Citocinas/efeitos dos fármacos , Citocinas/metabolismo , Decídua/imunologia , Ensaio de Imunoadsorção Enzimática , Membranas Extraembrionárias/imunologia , Feminino , Humanos , Interleucina-10/metabolismo , Interleucina-1beta/efeitos dos fármacos , Interleucina-6/metabolismo , Interleucina-8/efeitos dos fármacos , Metaloproteinase 9 da Matriz/efeitos dos fármacos , Progesterona/imunologia , Progestinas/imunologia , Estatísticas não Paramétricas , Fator de Necrose Tumoral alfa/efeitos dos fármacosRESUMO
PROBLEM: Infection of human fetal membranes elicits secretion of pro-inflammatory modulators through its innate immune capacities. We investigated the effect of lipopolysacharide (LPS) and progesterone (P4) upon expression of TLR-4/MyD88, TNFα, IL-6, IL-8, IL-10, and HBD2 on the human amniotic epithelium. METHOD OF STUDY: Explants of the human amniotic epithelium were pre-treated with 0.01, 0.1, and 1.0 µM of P4; then cotreated with 1000 ng/mL LPS. TLR-4 was immuno-detected, and concentrations of MyD88, TNFα, IL-6, IL-8, IL-10, and HBD2 were quantified by ELISA. RESULTS: P4 significantly reduced the expression of LPS-induced TLR-4/MyD88. LPS increased the concentrations of TNFα, IL-6, IL-8, IL-10, and HBD2 by factors of 30-, eight, three, three, and fivefold, respectively. P4 at 1.0 µM was the most effective dose to blunt the secretion of TNFα, IL-6, and HBD-2. RU-486 blocks the effect of P4. CONCLUSION: P4 inhibited LPS-induced TLR-4/MyD88 and pro-inflammatory factors in the human amniotic epithelium. These results could explain partially how P4 can protect the amniotic region of fetal membranes and generate a compensatory mechanism that limits the secretion of pro-inflammatory modulators, which could jeopardize the immune privilege during pregnancy.
Assuntos
Âmnio/citologia , Epitélio/imunologia , Progesterona/imunologia , Células Cultivadas , Citocinas/genética , Citocinas/metabolismo , Feminino , Regulação da Expressão Gênica , Antagonistas de Hormônios/farmacologia , Humanos , Tolerância Imunológica , Imunidade Inata , Mediadores da Inflamação/metabolismo , Lipopolissacarídeos/imunologia , Mifepristona/farmacologia , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , Gravidez , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo , beta-Defensinas/genética , beta-Defensinas/metabolismoRESUMO
Progesterone (P4) is a steroidal hormone with a vital role in the maintenance of human and animal health. This paper describes the development of an immunosensor coupled to glassy carbon (GC) electrode and integrated to a microfluidic system to quantify P4 from bovine serum samples in a fast and sensitive way. The serum samples spiked with a given P4 concentration and a given P4 concentration bound to horseradish peroxide (HPR) were simultaneously added and, therefore, they competed immunologically with sheep monoclonal anti-P4 antibodies that were immobilized at a rotating disk. HRP in the presence of hydrogen peroxide (H(2)O(2)) catalyzes the chatecol (H(2)Q) oxidation to benzoquinone (Q). Its reverse electrochemical reduction to H(2)Q can be detected at a GC electrode surface at -0.15 V by chronoamperometric measurements. These current responses are proportional to the enzyme activity and inversely proportional to the P4 amount present in bovine serum samples. This P4 immunosensor showed a linear working range from 0.5 to 12.5 ng mL(-1). The detection (DL) and quantification (QL) limits were 0.2 and 0.5 ng mL(-1), respectively. The electrochemical immunosensor had a higher sensitivity than the ELISA method using conventional spectrophotometric detections. However, both methods allowed us to obtain similar detection limits. The immunosensor allowed us to make up to 100 determinations on different samples without any previous pre-treatment. This behavior proved to be suitable to detect P4 in routine veterinary, clinical, biological, physiological, and analytical assays.
Assuntos
Técnicas Biossensoriais/instrumentação , Técnicas Imunoenzimáticas/instrumentação , Microfluídica/instrumentação , Progesterona/sangue , Animais , Técnicas Biossensoriais/métodos , Bovinos , Eletroquímica/instrumentação , Ensaio de Imunoadsorção Enzimática , Desenho de Equipamento , Análise de Injeção de Fluxo , Limite de Detecção , Modelos Lineares , Progesterona/imunologiaRESUMO
The clinical background, vertical transmission of Trichinella spiralis and helminthotoxic activity of sera were evaluated in four pregnant women infected at different gestation times. Parasitological and immunological parameters were analyzed. Patients presented clinical symptoms and a seroconversion pattern typical of Trichinella infection, independently of the gestation trimester. All patients, including one patient treated with mebendazole, gave birth to healthy infants at full term. Studies performed in placentas and umbilical cords by artificial digestion and/or immunofluorescence did not reveal the presence of parasites or parasite antigens. Specific antibodies were found in placental extraction and maternal sera by immunofluorescence, ELISA and/or immunoelectrotransfer blot assay. Specific IgG, IgE and IgA were found in the umbilical cord sera. One umbilical cord demonstrated immune-complexed specific IgM and circulating parasite antigens were found in the corresponding infant up to 10 months after birth. Patients' sera were able to kill newborn larvae in cytotoxicity assays, even in the absence of specific antibodies; this effect was abrogated by mifepristone. The results suggest that in human trichinellosis during pregnancy there is an enhanced helminthotoxicity to newborn larvae, dependent in part on progesterone, leading to a mild or moderate course of the infection. The results also indicate that the transplacental passage of migrating larvae is possible.
Assuntos
Antígenos de Helmintos/imunologia , Complicações Parasitárias na Gravidez/parasitologia , Trichinella spiralis , Triquinelose/imunologia , Adulto , Animais , Citotoxicidade Imunológica/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Sangue Fetal/parasitologia , Interações Hospedeiro-Parasita/imunologia , Humanos , Recém-Nascido , Transmissão Vertical de Doenças Infecciosas , Placenta/parasitologia , Gravidez , Complicações Parasitárias na Gravidez/imunologia , Resultado da Gravidez , Trimestres da Gravidez , Progesterona/imunologia , Trichinella spiralis/imunologiaRESUMO
La Colestasis Gravídica en un síndrome que habitualmente se produce en el tercer trimestre del embarazo y se resuelve en el embarazo. Se caracteriza clínicamente por la presencia de prurito, ictericia o ambos sin otra disfunción hepática importante. En el siguiente trabajo se reporta caso de paciente femenino de 24 años III gestas II para FUR: 12/8/06 quien refiere de 6 días de evolución orinas coluricas, prurito generalizado predominio de manos y tórax, exámenes para clínicos con aumento de un transaminasas, fosfatasas alcalinas, se diagnóstica colestasis gravídica, patología de baja incidencia de 1/300 y 1/2000 embarazos, se considera importante realizar una revisión académica del mismo.
Assuntos
Humanos , Adulto , Feminino , Gravidez , Cálculos da Bexiga Urinária/etiologia , Colestase Intra-Hepática/patologia , Colestase Intra-Hepática/terapia , Monoéster Fosfórico Hidrolases/imunologia , Melanose/diagnóstico , Melanose/terapia , Urina/citologia , Período Pós-Parto/fisiologia , Prurido/diagnóstico , Transaminases/imunologia , Estrogênios/imunologia , Cirurgia Geral , Icterícia Obstrutiva/diagnóstico , Icterícia Obstrutiva/patologia , Obstetrícia , Progesterona/imunologia , Sorologia/métodosRESUMO
We evaluated the role of estradiol and progesterone in allergic lung inflammation. Rats were ovariectomized (Ovx) and, 7 days later, were sensitized with ovalbumin (OA) and challenged after 2 wk with inhaled OA; experiments were performed 1 day thereafter. Ovx-allergic rats showed reduced cell recruitment into the bronchoalveolar lavage (BAL) fluid relative to sham-Ovx allergic rats, as was observed in intact allergic rats treated with ICI-182,780. Estradiol increased the number of cells in the BAL of Ovx-allergic rats, whereas progesterone induced an additional reduction. Cells of BAL and bone marrow (BM) of Ovx-allergic rats released elevated amounts of IL-10 and reduced IL-1beta and TNF-alpha. BM cells of Ovx-allergic rats released increased amounts of IL-10 and lower amounts of IL-4. Estradiol treatment of Ovx-allergic rats decreased the release of IL-10 but increased that of IL-4 by BM cells. Estradiol also caused an increased release of IL-1beta and TNF-alpha by BAL cells. Progesterone significantly increased the release of IL-10, IL-1beta, and TNF-alpha by BAL cells and augmented that of IL-4 by BM cells. Degranulation of bronchial mast cells from Ovx rats was reduced after in vitro challenge, an effect reverted by estradiol but not by progesterone. We suggest that the serum estradiol-to-progesterone ratio might drive cellular recruitment, modulating the pulmonary allergy and profile of release of anti-inflammatory or inflammatory cytokines. The existence of such dual hormonal effects suggests that the hormone therapy of asthmatic postmenopausal women and of those suffering of premenstrual asthma should take into account the possibility of worsening the pulmonary conditions.
Assuntos
Asma/imunologia , Asma/fisiopatologia , Citocinas/metabolismo , Estradiol/imunologia , Pneumonia/imunologia , Pneumonia/fisiopatologia , Progesterona/imunologia , Animais , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/imunologia , Líquido da Lavagem Broncoalveolar/citologia , Líquido da Lavagem Broncoalveolar/imunologia , Degranulação Celular/efeitos dos fármacos , Degranulação Celular/imunologia , Modelos Animais de Doenças , Estradiol/sangue , Estradiol/farmacologia , Feminino , Hipersensibilidade/imunologia , Hipersensibilidade/fisiopatologia , Interleucina-10/metabolismo , Interleucina-1beta/metabolismo , Interleucina-4/metabolismo , Contagem de Leucócitos , Mastócitos/efeitos dos fármacos , Mastócitos/imunologia , Ovalbumina/imunologia , Ovariectomia , Progesterona/sangue , Progesterona/farmacologia , Ratos , Ratos Wistar , Fator de Necrose Tumoral alfa/metabolismoRESUMO
PROBLEM: Several studies indicate that RANTES (regulated on activation, normal T cell expressed and secreted) is able to downregulate T-cell responses which suggest it might be relevant for fetal tolerance induction. However, the role of RANTES in pregnancy had not been established. Here we investigate RANTES regulation during early pregnancy and potential failures leading to losses of pregnancies. METHOD OF STUDY: RANTES and progesterone levels were determined in sera and feto-placental units from high resorption rate CBA/JxDBA/2 pregnant females and compared with CBA/JxBALB/c normal pregnant mice. RANTES in vitro modulation was also studied in nulliparous, primiparous and multiparous CBA/J and BALB/c cells in response to paternal alloantigen and progesterone stimulation. RESULTS: Nulliparous CBA/J females were quantitatively deficient in RANTES sera levels, whereas pregnancies with male BALB/c or DBA/2 increased its production. However, feto-placental units from CBA/J females are high producers of progesterone and RANTES. CONCLUSION: These data suggest that the beneficial effect of RANTES on feto-maternal interface requires an optimal concentration range and might be modulated by progesterone, hence exacerbated placental expression could be associated with high resorption rate.
Assuntos
Aborto Espontâneo/imunologia , Quimiocina CCL5/imunologia , Progesterona/imunologia , Aborto Espontâneo/sangue , Aborto Espontâneo/metabolismo , Animais , Quimiocina CCL5/sangue , Quimiocina CCL5/metabolismo , Feminino , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Camundongos Endogâmicos DBA , Placenta/imunologia , Placenta/metabolismo , Gravidez , Progesterona/biossíntese , Progesterona/sangueRESUMO
The aim of this work was to investigate the role of progesterone during Taenia crassiceps cysticercosis, and the immunological mechanisms involved in its effects, by relating progesterone treatment to whole parasite counts, to host humoral and cellular immune response, to the presence or absence of nuclear receptors to sex steroids in splenocytes, and to serum sex steroid levels in infected mice of both genders. Progesterone treatment increased parasite loads two-fold in females and three-fold in males compared with control mice. The expression of the Th2 cytokine profile (IL-4, IL-6 and IL-10) was markedly increased in infected mice of both genders, while progesterone treatment returned this expression to basal levels. However, the Th1 cytokine profile (IFN-gamma and TNF-alpha) was not affected by infection, whilst progesterone treatment increased the expression of both cytokines two-fold compared to uninfected, infected and placebo-treated mice. Testosterone serum levels decreased in infected male mice by 95%, and treatment with progesterone did not affect them. In females, no change in testosterone levels was observed. Progesterone levels increased three-fold only in progesterone-treated infected mice of both sexes, while estradiol levels in female and male progesterone-treated infected mice increased two-fold compared to infected control mice. The infection markedly induced the expression of progesterone receptor (PR) isoforms A and B in splenocytes of infected mice of both genders (five-fold). Metabolism of progesterone to estradiol was demonstrated by the use of the anti-estrogen tamoxifen, which reduced parasite loads 100% in infected mice of both sexes treated with progesterone. These results suggest that progesterone, possibly through its metabolism to estradiol, affects establishment, growth and reproduction of the helminth parasite T. crassiceps.
Assuntos
Cisticercose/imunologia , Estradiol/metabolismo , Progesterona/metabolismo , Progesterona/fisiologia , Animais , Castração , Citocinas/metabolismo , Estradiol/fisiologia , Estro , Feminino , Expressão Gênica , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Progesterona/imunologia , Tamoxifeno/farmacologiaRESUMO
PROBLEM: We have previously demonstrated that the addition of placental interleukin-6 (IL-6) to murine hybridomas increased asymmetric antibody synthesis. Here we analyze whether progesterone (Pg) and estrogen (E2) affect asymmetric antibody synthesis by modulating IL-6 production in hybridoma cells. METHOD OF STUDY: Hybridoma 112D5 B cells were cultured with E2, Pg or recombinant IL-6. Cell proliferation was assessed by 3H-thymidine incorporation, and asymmetric antibodies were measured in culture supernatants by Con A fixation and enzyme-linked immunusorbant assay (ELISA). E2 and Pg-receptors (ER and PR) were evaluated in whole cell extracts by Western blot. IL-6 was measured in culture supernatants by ELISA. RESULTS: 112D5 expressed both PR and ER, which were differentially regulated. At 48 hr, Pg and E2 slightly decreased cell proliferation whereas IL-6 did not. As well as IL-6, 10(-10) M Pg but not E2 induced asymmetric antibody production. Interestingly, Pg at 10(-6) M decreased asymmetric antibody synthesis by hybridoma cells. Finally, mainly Pg but also E2 increased IL-6 synthesis, although IL-6 levels did not correlate with asymmetric antibodies synthesized in the presence of E2 or Pg. CONCLUSIONS: In cells expressing both ER and PR, we could demonstrate that steroids participate in humoral immune responses by modulating asymmetric antibody synthesis. IL-6 proved to be only partially involved. Other possible mechanisms involved in the effect of Pg on blocking antibody responses and their contribution to a successful pregnancy are discussed in the paper.
Assuntos
Formação de Anticorpos/efeitos dos fármacos , Estrogênios/imunologia , Interleucina-6/imunologia , Progesterona/imunologia , Animais , Divisão Celular/efeitos dos fármacos , Estrogênios/farmacologia , Hibridomas/efeitos dos fármacos , Hibridomas/imunologia , Técnicas In Vitro , Camundongos , Progesterona/farmacologia , Receptores de Estrogênio/biossíntese , Receptores de Estrogênio/imunologia , Receptores de Progesterona/biossíntese , Receptores de Progesterona/imunologiaRESUMO
The purpose of the present study was to determine whether glucocorticoid inhibition of prolactin (PRL) release in oestrogen-treated ovariectomized (OVX) rats is mediated by endogenous opioid peptides (EOPs). All the animals were OVX and given oestradiol benzoate (OB, 20 microg/rat, s.c.) 2 weeks later (day 0). On day 3 they received vehicle, mifepristone (MIF, 10 mg/kg, s.c.) or hydrocortisone (HYD, 2 mg/rat, s.c.), in combination with the opioid antagonist naloxone (NAL, 2 mg/kg, i.p.) or vehicle. Serum PRL concentration was then measured by RIA at 13.00 and 18.00 hr, to include assessment of diurnal variation of PRL secretion. At 13.00 hr either MIF or NAL alone increased PRL secretion with no additional effect when NAL was combined with MIF. HYD had no significant inhibitory effect, but NAL with HYD increased PRL secretion. At 18.00 hr serum PRL concentration was higher than at 13.00 hr, and not affected significantly by MIF or NAL alone, although PRL secretion was increased by treatment with both. HYD inhibited PRL secretion and this inhibition was prevented by NAL. In a second experiment to distinguish antiglucocorticoid and antiprogesterone effects of MIF, we administered progesterone (2 mg/rat, s.c.) or a specific progesterone antiserum. In contrast with MIF, the progesterone antibody had no effect on PRL secretion at 13.00 hr, nor on the stimulation by NAL, while progesterone (unlike HYD) increased PRL secretion and NAL attenuated this response; this was opposite to the effect of NAL with HYD. Similarly, at 18.00 hr the interaction of MIF and NAL was not explained by antagonism of progesterone. Together, these results indicate inhibition of PRL by glucocorticoids but not progesterone, mediated in part by EOPs. At 18.00 hr endogenous glucocorticoids do not regulate oestrogen-stimulated PRL release, although HYD is inhibitory through EOPs.
Assuntos
Estradiol/farmacologia , Peptídeos Opioides/metabolismo , Ovariectomia , Prolactina/efeitos dos fármacos , Animais , Anti-Inflamatórios/farmacologia , Estradiol/administração & dosagem , Feminino , Antagonistas de Hormônios/farmacologia , Hidrocortisona/farmacologia , Mifepristona/farmacologia , Naloxona/farmacologia , Progesterona/imunologia , Progesterona/farmacologia , Prolactina/sangue , Prolactina/metabolismo , Ratos , Ratos Wistar/cirurgiaRESUMO
Accumulated evidence indicates that the adrenal cortex is able to regulate prolactin (PRL) secretion in rats. The aim of this study was to determine the participation of adrenal steroids on the regulation of PRL release in ovariectomized (OVX) and oestrogen-treated rats, by using mifepristone or a specific progesterone antiserum. Blood samples were obtained at 13:00 and 18:00 h 3 days after priming with oestradiol benzoate (OB). A significant increase in serum PRL at 13:00 and 18:00 h was induced by OB treatment. The administration of mifepristone to OVX and oestrogen-primed rats enhanced serum PRL increase at 13:00 h, without modifying the values at 18:00 h; while the administration of progesterone antiserum did not modify PRL levels, indicating that the effect of mifepristone on PRL secretion is due to its antiglucocorticoid action. Adrenalectomy induced a release of PRL at 13:00 h similar to that observed in the OVX and oestrogen-primed rats after mifepristone administration. Treatment with a low dose of progesterone (0.1 mg/rat) to OVX, adrenalectomized and oestrogen-primed rats did not modify the effect of adrenalectomy in serum PRL. Progesterone (2 mg/rat) given at 08:00 h to OVX and oestrogen-primed rats increased serum PRL 5 h later. Mifepristone treatment partially reverted the PRL increase induced by progesterone. These results suggest that after a previous sensitization of the pituitary by oestrogen, circulating glucocorticoids may exert a direct inhibitory effect on PRL release. This inhibition takes place at 13:00 h on day 3. On the other hand, the lack of effect of mifepristone or adrenalectomy on the PRL release at 18:00 h may also indicate that neither progesterone nor glucocorticoids modify PRL release induced by oestrogen at this time.
Assuntos
Córtex Suprarrenal/fisiologia , Estrogênios/farmacologia , Glucocorticoides/fisiologia , Mifepristona/farmacologia , Ovariectomia , Prolactina/metabolismo , Córtex Suprarrenal/efeitos dos fármacos , Adrenalectomia , Animais , Estradiol/farmacologia , Feminino , Soros Imunes/farmacologia , Cinética , Progesterona/imunologia , Progesterona/farmacologia , Progesterona/fisiologia , Ratos , Ratos WistarRESUMO
There is evidence that the adrenals play a role in the regulation of the synthesis and release of gonadotrophins in various vertebrates. The aim of this study was to determine the part played by adrenal steroids, with special reference to progesterone, on the concentration of LH in ovariectomized (OVX) and oestrogen-primed rats. OVX rats received a single s.c. injection of vehicle or oestradiol benzoate (OB, 20 micrograms/rat). This day was designated as day 0. Three or four days later (day 3-day 4), the rats were treated with mifepristone (10 mg/kg) or with two doses of progesterone antiserum and blood samples were obtained at 13.00 and 18.00 h. OB treatment of OVX rats reduced serum LH at 13.00 h and 18.00 h on day 3 but only at 13.00 h on day 4. The administration of mifepristone at 08.00 h to OVX and oestrogen-treated rats induced a significant increase in serum LH at 18.00 h on days 3 and 4, without modifying the values at 13.00 h. When mifepristone was given at 13.00 h a much larger increase in serum LH was obtained at 18.00 h. In OVX and oestrogen-treated rats, adrenalectomy on day 2 (08.00-09.00 h) induced an increase in serum LH at 18.00 h similar to that observed in the OVX and oestrogen-primed rats after mifepristone treatment. In order to determine the specificity of the effect of mifepristone, a group of OVX and oestrogen-treated rats was injected with progesterone antiserum at 08.00 and 13.00 h on day 3.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Estrogênios/fisiologia , Hormônio Luteinizante/metabolismo , Progesterona/fisiologia , Glândulas Suprarrenais/efeitos dos fármacos , Glândulas Suprarrenais/metabolismo , Adrenalectomia , Animais , Estradiol/farmacologia , Retroalimentação , Feminino , Soros Imunes/farmacologia , Hormônio Luteinizante/sangue , Mifepristona/farmacologia , Ovariectomia , Progesterona/imunologia , Progesterona/metabolismo , Radioimunoensaio , Ratos , Ratos WistarRESUMO
These studies examined the mechanisms responsible for the paucity of basal LH pulses during estrus. We confirmed our earlier observations that constant infusion of naloxone during estrus results in the immediate appearance of pulsatile LH secretion during estrus, consisting of LH peak heights and LH interpulse intervals that are similar to those observed during other days of the estrous cycle. We then tested whether the proestrous surge of progesterone was responsible for the suppression of pulsatile LH secretion during estrus. Three treatment regimens were used on proestrus to either block progesterone secretion (pentobarbital) or block its action (progesterone antiserum or the progesterone antagonist, RU 486). After treatment at 12.00 h on proestrus, blood samples were collected during estrus every 10 min for 4 h, and the plasma samples were analyzed for the pattern of LH secretion. Treatment with pentobarbital (35 mg/kg at 12:00 h) blocked the proestrous surges of LH and progesterone and resulted in pulsatile LH secretion during estrus. The LH interpulse interval (72 +/- 7 min) was somewhat slower than that observed in the naloxone-infused animals (54 +/- 8 min). Simultaneous treatment with pentobarbital and progesterone at 12:00 h on proestrus completely prevented the appearance of LH pulses during estrus. Treatment with either progesterone antiserum (0.5 ml, i.v.) or RU 486 (1 mg s.c.) resulted in the initiation of pulsatile LH secretion during estrus. In the RU 486-treated animals, LH peak heights and LH interpulse intervals were similar to those observed in naloxone-infused animals and during other days of the estrous cycle.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Estro/fisiologia , Hormônio Luteinizante/metabolismo , Proestro/fisiologia , Progesterona/metabolismo , Animais , Feminino , Imunização Passiva , Mifepristona/farmacologia , Naloxona/farmacologia , Pentobarbital/farmacologia , Periodicidade , Proestro/efeitos dos fármacos , Progesterona/antagonistas & inibidores , Progesterona/imunologia , Ratos , Ratos EndogâmicosRESUMO
We have previously found that modifications to serum progesterone concentration have profound inhibitory effects on prolactin release in response to ether stress. The objective of the present study was to determine the effect of ether stress on progesterone secretion and the role of this steroid in ether-induced prolactin release. Serum progesterone concentration, 5 min after ether stress had been applied over a 2-min period, was consistently increased in male rats, in cyclic rats on the mornings of pro-oestrus and oestrus, and in androgenized rats in permanent oestrus. Ovariectomized androgenized rats showed the same response. Adrenalectomy of male and female rats abolished the progesterone increase induced by stress. Thus, the progesterone secreted by stressed rats is mostly of adrenal origin. In groups of male and pro-oestrous rats, circulating concentrations of prolactin and progesterone were measured from 5 to 60 min after stress. In both sexes the serum prolactin concentration was significantly increased at only 5 and 10 min after stress when compared with control values. In pro-oestrous rats the serum progesterone concentration was significantly higher than in controls at 5, 10 and 20 min after stress, whilst in male rats the concentration remained significantly higher at 30 min. Thirty minutes after the first stress, male and proestrous rats were etherized for 2 min, and bled 5 min after removal from the ether container. In female rats this second stress produced only a slight but significant increase in serum prolactin concentrations, whereas in male rats prolactin concentrations did not increase.(ABSTRACT TRUNCATED AT 250 WORDS)