Oestrogens down-regulate type I but not type II adrenal corticoid receptors in rat anterior pituitary.
J Steroid Biochem
; 35(6): 671-7, 1990 May.
Article
em En
| MEDLINE
| ID: mdl-2163470
We have studied type I and type II adrenal cortical steroid receptors in the anterior (AL), intermediate (IL) and posterior (PL) lobes of the pituitary and in the hippocampus of ovariectomized-adrenalectomized female rats and in castrated-adrenalectomized male animals, with or without oestrogen treatment. Using [3H]dexamethasone as ligand and conditions suitable for determination of its binding to type I and type II receptors, we found that 4 or 15 days of oestrogen reduced type I receptors in AL by 50-60% without changes in IL, PL or hippocampus, or in type II sites in any of the four neuroendocrine tissues studied. This down-regulatory effect was seen only in female rats and no change was found for males. The reduction in type I sites in AL in oestrogenized female rats was confirmed by labelling type I sites with the synthetic antimineralocorticoid [3H]ZK 91587. Saturation analysis with [3H]ZK 91587 demonstrated that the reduction was due to a reduction in Bmax without change in Kd. We conclude that: (a) type I receptors in the anterior pituitary are under oestrogenic control; (b) there is a sex difference in the response to oestrogen of AL type I sites; and (c) this demonstration may be useful in determining the role of type I receptors in neuroendocrine regulation of the anterior pituitary by hormones derived from the adrenal cortex, and the participation of sex hormones in this process.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Adeno-Hipófise
/
Receptores do Hormônio Hipofisário
/
Regulação para Baixo
/
Hormônio Adrenocorticotrópico
/
Estradiol
Limite:
Animals
Idioma:
En
Revista:
J Steroid Biochem
Ano de publicação:
1990
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Reino Unido