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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
23/04/2003 |
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Data da última atualização: |
23/10/2019 |
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Autoria: |
ELOY, A. M. X. |
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Afiliação: |
ANGELA MARIA XAVIER ELOY, CNPC. |
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Título: |
Stress, opioid peptides and luteinizing hormone secretion in ewes. |
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Ano de publicação: |
1995 |
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Fonte/Imprenta: |
1995. |
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Páginas: |
172 f. |
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Idioma: |
Inglês |
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Notas: |
Thesis (Doctor of Phylosophy) - University of Leeds, Leeds. |
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Conteúdo: |
The studies performed in this thesis aim to clarify the effects of physiologicaI and psychologicaI stresses on the plasma concentrations of cortisol and B-endorphin and the consequent effects on gonadotropin (LH) release in long-term ovariectomized ewes. AIso, a study was made of the. endogenous opioid involvement during application of these two kinds of stressors through the use of an opioid antagonist (naloxone). In this work not only was the peripheraI effect of naloxone evaluated but also its central action on the hypothalamo-pituitary adrenal axis activity and gonadotropin (LH) release. Plasma concentrations of B-endorphin and cortisol were elevated during acute (4 hours) insulin-induced hypoglycemia (2mU/kg/min) stress while plasma LH concentrations were inhibited. Infusion of the opioid antagonist naIoxone hydrochloride (5.5ug/kg/min) blocked the inhibitory effect of B-endorphin on LH release. It was concluded that endogenous opioids are involved in the control of LH release during hypoglycemia in ovariectomized ewes. In addition, this experiment detected no effect of acute hypoglycemia on episodic LH in ovariectomized animais. However, it was possible to observe a stimulatory effect of naIoxone on the LH pulse frequency in the first two hours after the beginning of the infusion, suggesting that this antagonist has short half life. During chronic (12 hours) insulin-induced hypoglycemia (2mU/kg/min), plasma ,B-endorphin levels retumed to basal levels while plasma cortisol concentrations showed a rise, suggesting incomplete feedback of corticosteroids on ACTH. LH levels remained low even during control treatment and naloxone (5.5Jlg/kg/min) infusion was not ~ble to stimulate the release of this hormone. In this case the long absence of ovarian steroids could be responsible for the lack of naloxone response and siso for the low levels of LH during saline infusion. The isolation stress that was used in this experiment allowed no visual contact but vocal communication was possible between the animaIs and lasted four hours. This caused a rise in the plasma {3-endorphin levels soon after the beginning of the stress procedure and a depression of the plasma LH leyels. Intravenous injection of naloxone (1 mg/kg) was capable of disinhibiting the LH response, suggesting the involvement of endogenous opioids in the control of LH during isolation stress. The isolation procedure did not significantly affect LH pulsatility. When the two stressors (hypoglycemia and isolation) were imposed together, plasma {3-endorphin concentrations Tose and plasma LH values were reduced. The LH pulse amplitude was affected suggesting a synergistic action of these two stressors on the GnRH pulse generator. When naIoxone (1 and 2 mg) was administered into the third ventricle to hypoglycemic animaIs made using insulin (1 mg/kg/i. v.) a blockade of the inhibitory effect of this stress on plasma LH concentrations was seen. However, naloxone had no effect on plasma LH when injected in animaIs under basal conditions. Plasma {3-endorphin and cortisol concentrations were depressed by i.c. v. injection of naloxone (2 mg) in hypoglycemic animais, but these hormones were not atfected in non-stressed animais. The intracerebroventricular injection of naloxone affected the LH pulse amplitude in hypoglycemic ewes. It is suggested that naloxone acts at the centraI nervous system, to regulate gonadotropin releasing hormone release in stressed animals. MenosThe studies performed in this thesis aim to clarify the effects of physiologicaI and psychologicaI stresses on the plasma concentrations of cortisol and B-endorphin and the consequent effects on gonadotropin (LH) release in long-term ovariectomized ewes. AIso, a study was made of the. endogenous opioid involvement during application of these two kinds of stressors through the use of an opioid antagonist (naloxone). In this work not only was the peripheraI effect of naloxone evaluated but also its central action on the hypothalamo-pituitary adrenal axis activity and gonadotropin (LH) release. Plasma concentrations of B-endorphin and cortisol were elevated during acute (4 hours) insulin-induced hypoglycemia (2mU/kg/min) stress while plasma LH concentrations were inhibited. Infusion of the opioid antagonist naIoxone hydrochloride (5.5ug/kg/min) blocked the inhibitory effect of B-endorphin on LH release. It was concluded that endogenous opioids are involved in the control of LH release during hypoglycemia in ovariectomized ewes. In addition, this experiment detected no effect of acute hypoglycemia on episodic LH in ovariectomized animais. However, it was possible to observe a stimulatory effect of naIoxone on the LH pulse frequency in the first two hours after the beginning of the infusion, suggesting that this antagonist has short half life. During chronic (12 hours) insulin-induced hypoglycemia (2mU/kg/min), plasma ,B-endorphin levels retumed to basal levels while plasma corti... Mostrar Tudo |
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Palavras-Chave: |
Hormônio luteinizante; LH; Secreção de hormônio. |
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Thesagro: |
Endocrinologia; Ovelha; Ovino; Reprodução Animal. |
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Thesaurus Nal: |
Animal nutrition; Animal physiology; Ewes; Sheep. |
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Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
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Marc: |
LEADER 04171nam a2200265 a 4500
001 1529254
005 2019-10-23
008 1995 bl uuuu m 00u1 u #d
100 1 $aELOY, A. M. X.
245 $aStress, opioid peptides and luteinizing hormone secretion in ewes.
260 $a1995.$c1995
300 $a172 f.
500 $aThesis (Doctor of Phylosophy) - University of Leeds, Leeds.
520 $aThe studies performed in this thesis aim to clarify the effects of physiologicaI and psychologicaI stresses on the plasma concentrations of cortisol and B-endorphin and the consequent effects on gonadotropin (LH) release in long-term ovariectomized ewes. AIso, a study was made of the. endogenous opioid involvement during application of these two kinds of stressors through the use of an opioid antagonist (naloxone). In this work not only was the peripheraI effect of naloxone evaluated but also its central action on the hypothalamo-pituitary adrenal axis activity and gonadotropin (LH) release. Plasma concentrations of B-endorphin and cortisol were elevated during acute (4 hours) insulin-induced hypoglycemia (2mU/kg/min) stress while plasma LH concentrations were inhibited. Infusion of the opioid antagonist naIoxone hydrochloride (5.5ug/kg/min) blocked the inhibitory effect of B-endorphin on LH release. It was concluded that endogenous opioids are involved in the control of LH release during hypoglycemia in ovariectomized ewes. In addition, this experiment detected no effect of acute hypoglycemia on episodic LH in ovariectomized animais. However, it was possible to observe a stimulatory effect of naIoxone on the LH pulse frequency in the first two hours after the beginning of the infusion, suggesting that this antagonist has short half life. During chronic (12 hours) insulin-induced hypoglycemia (2mU/kg/min), plasma ,B-endorphin levels retumed to basal levels while plasma cortisol concentrations showed a rise, suggesting incomplete feedback of corticosteroids on ACTH. LH levels remained low even during control treatment and naloxone (5.5Jlg/kg/min) infusion was not ~ble to stimulate the release of this hormone. In this case the long absence of ovarian steroids could be responsible for the lack of naloxone response and siso for the low levels of LH during saline infusion. The isolation stress that was used in this experiment allowed no visual contact but vocal communication was possible between the animaIs and lasted four hours. This caused a rise in the plasma {3-endorphin levels soon after the beginning of the stress procedure and a depression of the plasma LH leyels. Intravenous injection of naloxone (1 mg/kg) was capable of disinhibiting the LH response, suggesting the involvement of endogenous opioids in the control of LH during isolation stress. The isolation procedure did not significantly affect LH pulsatility. When the two stressors (hypoglycemia and isolation) were imposed together, plasma {3-endorphin concentrations Tose and plasma LH values were reduced. The LH pulse amplitude was affected suggesting a synergistic action of these two stressors on the GnRH pulse generator. When naIoxone (1 and 2 mg) was administered into the third ventricle to hypoglycemic animaIs made using insulin (1 mg/kg/i. v.) a blockade of the inhibitory effect of this stress on plasma LH concentrations was seen. However, naloxone had no effect on plasma LH when injected in animaIs under basal conditions. Plasma {3-endorphin and cortisol concentrations were depressed by i.c. v. injection of naloxone (2 mg) in hypoglycemic animais, but these hormones were not atfected in non-stressed animais. The intracerebroventricular injection of naloxone affected the LH pulse amplitude in hypoglycemic ewes. It is suggested that naloxone acts at the centraI nervous system, to regulate gonadotropin releasing hormone release in stressed animals.
650 $aAnimal nutrition
650 $aAnimal physiology
650 $aEwes
650 $aSheep
650 $aEndocrinologia
650 $aOvelha
650 $aOvino
650 $aReprodução Animal
653 $aHormônio luteinizante
653 $aLH
653 $aSecreção de hormônio
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Embrapa Caprinos e Ovinos (CNPC) |
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Registro Completo
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Biblioteca(s): |
Embrapa Arroz e Feijão. |
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Data corrente: |
07/11/2011 |
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Data da última atualização: |
12/12/2011 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Circulação/Nível: |
B - 1 |
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Autoria: |
LITHOLDO JÚNIOR, C. G.; GOMES, E. V.; LOBO JUNIOR, M.; NASSER, L. C. B.; PETROFEZA, S. |
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Afiliação: |
C. G. LITHOLDO JÚNIOR, UFG; E. V. GOMES, UFG; MURILLO LOBO JUNIOR, CNPAF; LUIZ CARLOS BHERING NASSER; SILVANA PETROFEZA. |
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Título: |
Genetic diversity and mycelial compatibility groups of the plant-pathogenic fungus Sclerotinia sclerotiorum in Brazil. |
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Ano de publicação: |
2011 |
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Fonte/Imprenta: |
Genetics and Molecular Research, v. 10, n. 2, p. 868-877, 2011. |
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Idioma: |
Inglês |
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Conteúdo: |
The genetic variability of 40 Sclerotinia sclerotiorum isolates from various fields widely distributed throughout Brazil and different host crops was analyzed using RAPD markers and mycelial compatibility groupings (MCGs). The isolates were characterized using 16 random primers of the OPERON series, which produced 121 DNA fragments. UPGMA cluster analysis using Jaccard?s genetic distance and MCGs allowed separation of the isolates into three clusters, with similarity indices of 68.2, 61.8, and 61.8%, and five MCGs. The haplotypes obtained with RAPD markers provided very characteristic groupings of S. sclerotiorum isolates according to MCG, but did not show any relationship with geographic origin or host type. Furthermore, analysis of molecular variance demonstrated that 99.1% of the observed variation was a result of genetic differences between individuals; the host culture did not have a significant effect. This is the first report of high level variability of S. sclerotiorum in Brazil based on the study of isolates of wide geographical origin, supported by RAPD markers and MCGs. These results endorse the prevalence of sexual reproduction in tropical and subtropical regions in contrast to clonal reproduction in temperate regions. |
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Palavras-Chave: |
Diversidade genética. |
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Thesagro: |
Mofo branco; Sclerotinia sclerotiorum. |
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Categoria do assunto: |
H Saúde e Patologia |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/45576/1/gmr9371.pdf
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Marc: |
LEADER 01919naa a2200205 a 4500
001 1905022
005 2011-12-12
008 2011 bl uuuu u00u1 u #d
100 1 $aLITHOLDO JÚNIOR, C. G.
245 $aGenetic diversity and mycelial compatibility groups of the plant-pathogenic fungus Sclerotinia sclerotiorum in Brazil.$h[electronic resource]
260 $c2011
520 $aThe genetic variability of 40 Sclerotinia sclerotiorum isolates from various fields widely distributed throughout Brazil and different host crops was analyzed using RAPD markers and mycelial compatibility groupings (MCGs). The isolates were characterized using 16 random primers of the OPERON series, which produced 121 DNA fragments. UPGMA cluster analysis using Jaccard?s genetic distance and MCGs allowed separation of the isolates into three clusters, with similarity indices of 68.2, 61.8, and 61.8%, and five MCGs. The haplotypes obtained with RAPD markers provided very characteristic groupings of S. sclerotiorum isolates according to MCG, but did not show any relationship with geographic origin or host type. Furthermore, analysis of molecular variance demonstrated that 99.1% of the observed variation was a result of genetic differences between individuals; the host culture did not have a significant effect. This is the first report of high level variability of S. sclerotiorum in Brazil based on the study of isolates of wide geographical origin, supported by RAPD markers and MCGs. These results endorse the prevalence of sexual reproduction in tropical and subtropical regions in contrast to clonal reproduction in temperate regions.
650 $aMofo branco
650 $aSclerotinia sclerotiorum
653 $aDiversidade genética
700 1 $aGOMES, E. V.
700 1 $aLOBO JUNIOR, M.
700 1 $aNASSER, L. C. B.
700 1 $aPETROFEZA, S.
773 $tGenetics and Molecular Research$gv. 10, n. 2, p. 868-877, 2011.
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Embrapa Arroz e Feijão (CNPAF) |
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