RESUMO
Chronic stress is related to the acceleration of telomere shortening. Recent work showed a correlation between chronic psychosocial stress and reduced telomere length in certain cells. The exposure of T lymphocytes to cortisol promoted a significant reduction in telomerase activity. Although stress can promote changes in telomere length, whether increased glucocorticoid concentrations alter telomere length in brain tissue cells is unclear. In addition to modulating the activity of the stress system, estrogen also influences telomere length. The objective of this study was to verify whether chronic exposure to glucocorticoids promotes changes in the telomere length of encephalic areas involved in the control of HPA axis activity and whether estrogen affects these changes. Wistar rats were ovariectomized and treated with estradiol cypionate [(50 or 100 µg/kg, subcutaneously)] or oil and 20 mg/kg corticosterone or vehicle (isotonic saline with 2% Tween 80, subcutaneously) for 28 days. On the day after the end of the hormonal treatment, the animals were euthanized for collection of blood, brain and pituitary gland samples. Estrogen modulated the activity of the HPA axis. CRH, AVP and POMC mRNA levels were reduced by estrogen. At least in doses and treatment time used, there was no correlation between effects of exposure to glucocorticoids and estrogen on telomere length in the brain areas of female rats. However, estrogen treatment reduced the telomere length in the central amygdala and dorsal hippocampus, but not in the PVN, indicating a variation of reaction of telomeres for estrogen in different brain areas.
Assuntos
Corticosterona/farmacologia , Estrogênios/farmacologia , Homeostase do Telômero/fisiologia , Hormônio Adrenocorticotrópico/metabolismo , Tonsila do Cerebelo/efeitos dos fármacos , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Corticosterona/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Estrogênios/metabolismo , Feminino , Hipocampo/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/metabolismo , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Sistema Hipófise-Suprarrenal/metabolismo , Ratos , Estresse Fisiológico , Telômero/efeitos dos fármacos , Telômero/metabolismo , Telômero/fisiologia , Homeostase do Telômero/efeitos dos fármacosRESUMO
Two polymorphisms (GHC and GHD) in the growth hormone gene were evaluated in the ninety-six (96) animals of three breeds of pigs (Pietrain, Large White, and Landrace), through PCR-RFLP. Allele frequencies observed for the GHC polymorphism were: C1 0.42, C2 0.0, C3 0.06 and C4 0.52 for Landrace; C1 0.0, C2 0.03, C3 0.14 and C4 0.83 for Large White and C1 0.02, C2 0.25, C3 0.28 and C4 0.45 for Pietrain. The GHD polymorphism presented the following allele frequencies:. D1 0.69 and D2 0.31 for Landrace; D1 0.25 and D2 0.75 for Large White and D1 0.72 and D2 0.28 for Pietrain.
Dois polimorfismos (GHC e GHD) no gene que codifica para o hormônio do crescimento foram determinados em um total de 96 animais de três raças de suínos (Pietrain, Large White e Landrace), através da PCR-RFLP. As freqüências alélicas observadas para GHC foram C1 0,42, C2 0,0, C3 0,06 e C4 0,52 para Landrace; C1 0,0, C2 0,03, C3 0,14 e C4 0,83 para Large White e C1 0,02, C2 0,25, C3 0,28 e C4 0,45 para Pietrain. Para GHD, as freqüências alélicas observadas foram D1 0,69 e D2 0,31 para Landrace; D1 0,25 e D2 0,75 para Large White e D1 0,72 e D2 0,28 para Pietrain.
RESUMO
Two polymorphisms (GHC and GHD) in the growth hormone gene were evaluated in the ninety-six (96) animals of three breeds of pigs (Pietrain, Large White, and Landrace), through PCR-RFLP. Allele frequencies observed for the GHC polymorphism were: C1 0.42, C2 0.0, C3 0.06 and C4 0.52 for Landrace; C1 0.0, C2 0.03, C3 0.14 and C4 0.83 for Large White and C1 0.02, C2 0.25, C3 0.28 and C4 0.45 for Pietrain. The GHD polymorphism presented the following allele frequencies:. D1 0.69 and D2 0.31 for Landrace; D1 0.25 and D2 0.75 for Large White and D1 0.72 and D2 0.28 for Pietrain.
Dois polimorfismos (GHC e GHD) no gene que codifica para o hormônio do crescimento foram determinados em um total de 96 animais de três raças de suínos (Pietrain, Large White e Landrace), através da PCR-RFLP. As freqüências alélicas observadas para GHC foram C1 0,42, C2 0,0, C3 0,06 e C4 0,52 para Landrace; C1 0,0, C2 0,03, C3 0,14 e C4 0,83 para Large White e C1 0,02, C2 0,25, C3 0,28 e C4 0,45 para Pietrain. Para GHD, as freqüências alélicas observadas foram D1 0,69 e D2 0,31 para Landrace; D1 0,25 e D2 0,75 para Large White e D1 0,72 e D2 0,28 para Pietrain.