MEDIATED BY THE B-RECEPTOR IN RATS

Citation
As. Belloni et al., MEDIATED BY THE B-RECEPTOR IN RATS, Hypertension, 27(5), 1996, pp. 1153-1159
Citations number
51
Categorie Soggetti
Cardiac & Cardiovascular System
Journal title
ISSN journal
0194911X
Volume
27
Issue
5
Year of publication
1996
Pages
1153 - 1159
Database
ISI
SICI code
0194-911X(1996)27:5<1153:MBTBIR>2.0.ZU;2-5
Abstract
We investigated the gene expression and localization of endothelin-l ( ET-1) receptor subtypes ET(A) and ET(B) in the rat adrenal cortex as w ell as their involvement in the corticosteroid secretagogue effect of ET-1 in vitro. Reverse transcription-polymerase chain reaction with pr imers specific for ET(A) and ET(B) cDNAs demonstrated the expression o f both receptor genes in homogenates of adrenocortical tissue. However , in isolated zona glomerulosa and zona fasciculata cells, only ET(B) mRNA was detected. Autoradiographic examination of the selective displ acement of I-125-ET-1 binding by BQ-123 and BQ-788 (specific ligands f or ET(A) and ET(B), respectively) indicated that zona glomerulosa poss esses both ET(A) and ET(B), whereas zona fasciculata is exclusively pr ovided with ET(B). ET-1 enhanced in a concentration-dependent manner a ldosterone and corticosterone secretions of dispersed zona glomerulosa and zona fasciculata cells, respectively. The ET(B) antagonist BQ-788 markedly reduced the secretory response of zona glomerulosa cells and completely suppressed that of zona fasciculata cells, whereas the ET( A) antagonist BQ-123 was ineffective. These findings indicate that in the rat, the adrenocortical secretagogue action of ET-1 is mediated by the ETB receptor subtype and that the ET(A) receptor is not directly involved in such an effect.