Artigo

Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro

We investigated the participation of A1 or A2 receptors in the gonadotrope and their role in the regulation of LH and FSH secretion in adult rat hemipituitary preparations, using adenosine analogues. A dose-dependent inhibition of LH and FSH secretion was observed after the administration of graded...

ver descrição completa

Autor principal: DINIZ, Domingos Luiz Wanderley Picanço
Outros Autores: VALENÇA, Marcelo Moraes, FAVARETTO, Ana Lucia Vianna, MCCANN, S.M., RODRIGUES, José Antunes
Grau: Artigo
Idioma: eng
Publicado em: 2012
Assuntos:
Pituitária anterior
Adenosina
Hormônio folículo estimulante
Hormônio luteinizante
Receptor A1
Acesso em linha: http://repositorio.ufpa.br/jspui/handle/2011/3292
id ir-2011-3292
recordtype dspace
spelling ir-2011-32922018-01-10T15:32:52Z Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro DINIZ, Domingos Luiz Wanderley Picanço VALENÇA, Marcelo Moraes FAVARETTO, Ana Lucia Vianna MCCANN, S.M. RODRIGUES, José Antunes Pituitária anterior Adenosina Hormônio folículo estimulante Hormônio luteinizante Receptor A1 We investigated the participation of A1 or A2 receptors in the gonadotrope and their role in the regulation of LH and FSH secretion in adult rat hemipituitary preparations, using adenosine analogues. A dose-dependent inhibition of LH and FSH secretion was observed after the administration of graded doses of the R-isomer of phenylisopropyladenosine (R-PIA; 1 nM, 10 nM, 100 nM, 1 µM and 10 µM). The effect of R-PIA (10 nM) was blocked by the addition of 8-cyclopentyltheophylline (CPT), a selective A1 adenosine receptor antagonist, at the dose of 1 µM. The addition of an A2 receptor-specific agonist, 5-N-methylcarboxamidoadenosine (MECA), at the doses of 1 nM to 1 µM had no significant effect on LH or FSH secretion, suggesting the absence of this receptor subtype in the gonadotrope. However, a sharp inhibition of the basal secretion of these gonadotropins was observed after the administration of 10 µM MECA. This effect mimicked the inhibition induced by R-PIA, supporting the hypothesis of the presence of A1 receptors in the gonadotrope. R-PIA (1 nM to 1 µM) also inhibited the secretion of LH and FSH induced by phospholipase C (0.5 IU/ml) in a dose-dependent manner. These results suggest the presence of A1 receptors and the absence of A2 receptors in the gonadotrope. It is possible that the inhibition of LH and FSH secretion resulting from the activation of A1 receptors may have occurred independently of the increase in membrane phosphoinositide synthesis. 2012-12-20T15:48:28Z 2012-12-20T15:48:28Z 1999-09 Artigo de Periódico PICANÇO-DINIZ, D.L.W. et al. Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro. Brazilian Journal of Medical and Biological Research, Ribeirão Preto, v. 32, n. 9, p. 1167-1173, set. 1999. Disponível em: <http://www.scielo.br/pdf/bjmbr/v32n9/3518c.pdf>. Acesso em: 11 dez. 2012. http://dx.doi.org/10.1590/S0100-879X1999000900017. 1414-431X http://repositorio.ufpa.br/jspui/handle/2011/3292 eng Acesso Aberto application/pdf
institution Repositório Institucional - Universidade Federal do Pará
collection RI-UFPA
language eng
topic Pituitária anterior
Adenosina
Hormônio folículo estimulante
Hormônio luteinizante
Receptor A1
spellingShingle Pituitária anterior
Adenosina
Hormônio folículo estimulante
Hormônio luteinizante
Receptor A1
DINIZ, Domingos Luiz Wanderley Picanço
Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro
topic_facet Pituitária anterior
Adenosina
Hormônio folículo estimulante
Hormônio luteinizante
Receptor A1
description We investigated the participation of A1 or A2 receptors in the gonadotrope and their role in the regulation of LH and FSH secretion in adult rat hemipituitary preparations, using adenosine analogues. A dose-dependent inhibition of LH and FSH secretion was observed after the administration of graded doses of the R-isomer of phenylisopropyladenosine (R-PIA; 1 nM, 10 nM, 100 nM, 1 µM and 10 µM). The effect of R-PIA (10 nM) was blocked by the addition of 8-cyclopentyltheophylline (CPT), a selective A1 adenosine receptor antagonist, at the dose of 1 µM. The addition of an A2 receptor-specific agonist, 5-N-methylcarboxamidoadenosine (MECA), at the doses of 1 nM to 1 µM had no significant effect on LH or FSH secretion, suggesting the absence of this receptor subtype in the gonadotrope. However, a sharp inhibition of the basal secretion of these gonadotropins was observed after the administration of 10 µM MECA. This effect mimicked the inhibition induced by R-PIA, supporting the hypothesis of the presence of A1 receptors in the gonadotrope. R-PIA (1 nM to 1 µM) also inhibited the secretion of LH and FSH induced by phospholipase C (0.5 IU/ml) in a dose-dependent manner. These results suggest the presence of A1 receptors and the absence of A2 receptors in the gonadotrope. It is possible that the inhibition of LH and FSH secretion resulting from the activation of A1 receptors may have occurred independently of the increase in membrane phosphoinositide synthesis.
format Artigo
author DINIZ, Domingos Luiz Wanderley Picanço
author2 VALENÇA, Marcelo Moraes
FAVARETTO, Ana Lucia Vianna
MCCANN, S.M.
RODRIGUES, José Antunes
author2Str VALENÇA, Marcelo Moraes
FAVARETTO, Ana Lucia Vianna
MCCANN, S.M.
RODRIGUES, José Antunes
title Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro
title_short Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro
title_full Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro
title_fullStr Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro
title_full_unstemmed Possible involvement of A1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro
title_sort possible involvement of a1 receptors in the inhibition of gonadotropin secretion induced by adenosine in rat hemipituitaries in vitro
publishDate 2012
url http://repositorio.ufpa.br/jspui/handle/2011/3292
_version_ 1832603009719205888
score 11.755432

Registros relacionados