11Beta-hydroxysteroid dehydrogenase 1 transforms 11-dehydrocorticosterone into transcriptionally active glucocorticoid in neonatal rat heart.

Abstract:

:The ability of cells to directly respond to glucocorticoids and aldosterone is a function of GR and MR expression, and coexpression of 11beta-hydroxysteroid dehydrogenases (11betaHSDs), which convert glucocorticoids and their 11-ketometabolites into either receptor inactive or active derivatives. The aim of the present study was to determine the cellular expression of GR, MR, 11betaHSD1, and 11betaHSD2 in neonatal rat heart and determine the role these enzymes play in modulating glucocorticoid and aldosterone action. Ribonuclease protection analysis and steroid binding assays showed that GR is expressed in both cardiac myocytes and fibroblasts, whereas MR is expressed only in myocytes. 11betaHSD2 was not detected in cardiac cells, but 11betaHSD1 was expressed at high levels in both cardiac myocytes and fibroblasts. Enzyme activity studies demonstrated that 11betaHSD1 acted as a reductase only, converting biologically inactive 11-dehydrocorticosterone to corticosterone, which then stimulated serum and glucocorticoid-induced kinase gene transcription via GR. In both cardiac myocytes and fibroblasts, aldosterone stimulated serum and glucocorticoid-induced kinase gene expression exclusively via GR, but not MR, indicating that aldosterone can have glucocorticoid-like actions in heart. The ability of cardiac cells to use both circulating corticosterone and 11-dehydrocorticosterone as a source of glucocorticoid suggests that the heart is under tonic glucocorticoid control, implying that glucocorticoids play important homeostatic roles in the heart.

journal_name

Endocrinology

journal_title

Endocrinology

authors

Sheppard KE,Autelitano DJ

doi

10.1210/endo.143.1.8583

subject

Has Abstract

pub_date

2002-01-01 00:00:00

pages

198-204

issue

1

eissn

0013-7227

issn

1945-7170

journal_volume

143

pub_type

杂志文章