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Hypothyroid state reduces calcium channel function in 18-day pregnant rat uterus.
Indian J Exp Biol ; 2006 Jan; 44(1): 19-27
Artigo em Inglês | IMSEAR | ID: sea-58966
ABSTRACT
Hypothyroidism significantly reduced the mean amplitude and increased the mean frequency of spontaneous rhythmic contractions in 18 day pregnant rat uterus. Nifedipine (10(-12)-10(-9) M) and diltiazem (10(-10)-10(-6) M) caused concentration related inhibition of the myogenic responses of the uterine strips obtained from both pregnant and hypothyroid state. However, nifedipine was less potent (IC502.11 x 10(-11) M) in pregnant hypothyroid state as compared to pregnant control (IC50 3.1 x 10(-12) M). Similarly, diltiazem was less potent (IC50 3.72 x 10(-9) M) in inhibiting the uterine spontaneous contractions in hypothyroid than in pregnant rat uterus (IC505.37 x 10(-10) M). A similar decrease in the sensitivity to nifedipine and diltiazem for reversal of K+ (100 mM)-induced tonic contraction and K(+)-stimulated 45Ca2+ influx was observed with these calcium channel antagonists in uterus obtained from hypothyroid pregnant rats compared to the controls. Nifedipine-sensitive influx of 45Ca(2+)-stimulated either by K+ (100 mM) or by Bay K8644 (1,4-dihydro-2,6-methyl-5-nitro-4-[2'-(trifluromethyl)phenyl]-3-pyridine carboxylic acid methyl ester) (10(-9) M) was significantly less in uterine strips from hypothyroid rats compared to controls. The results suggest that the inhibition of uterine rhythmic contractions may be attributable to a reduction in rat myometrial Ca2+ channel function in the hypothyroid state.
Assuntos
Texto completo: DisponíveL Índice: IMSEAR (Sudeste Asiático) Assunto principal: Complicações na Gravidez / Ratos / Hormônios Tireóideos / Contração Uterina / Útero / Feminino / Gravidez / Bloqueadores dos Canais de Cálcio / Diltiazem / Nifedipino Idioma: Inglês Revista: Indian J Exp Biol Ano de publicação: 2006 Tipo de documento: Artigo

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Texto completo: DisponíveL Índice: IMSEAR (Sudeste Asiático) Assunto principal: Complicações na Gravidez / Ratos / Hormônios Tireóideos / Contração Uterina / Útero / Feminino / Gravidez / Bloqueadores dos Canais de Cálcio / Diltiazem / Nifedipino Idioma: Inglês Revista: Indian J Exp Biol Ano de publicação: 2006 Tipo de documento: Artigo