title: DHEA prevents mineralo- and glucocorticoid receptor-induced chronotropic and hypertrophic actions in isolated rat cardiomyocytes.
abstract: Corticosteroids have been involved in the genesis of ventricular arrhythmias associated with pathological heart hypertrophy, although molecular mechanisms responsible for these effects have not been completely explained. Because mineralocorticoid receptor (MR) antagonists have been demonstrated to be beneficial on the cardiac function, much attention has been given to the action of aldosterone on the heart. However, we have previously shown that both aldosterone and corticosterone in vitro induce a marked acceleration of the spontaneous contractions, as well as a significant cell hypertrophy in isolated neonate rat ventricular cardiomyocytes. Moreover, a beneficial role of the steroid hormone dehydroepiandrosterone (DHEA) has been also proposed, but the mechanism of its putative cardioprotective function is not known. We found that DHEA reduces both the chronotropic and the hypertrophic responses of cardiomyocytes upon stimulation of MR and glucocorticoid receptor (GR) in vitro. DHEA inhibitory effects were accompanied by a decrease of T-type calcium channel expression and activity, as assessed by quantitative PCR and the patch-clamp technique. Prevention of cell hypertrophy by DHEA was also revealed by measuring the expression of A-type natriuretic peptide and BNP. The kinetics of the negative chronotropic effect of DHEA, and its sensitivity to actinomycin D, pointed out the presence of both genomic and nongenomic mechanisms of action. Although the genomic action of DHEA was effective mostly upon MR activation, its rapid, nongenomic response appeared related to DHEA antioxidant properties. On the whole, these results suggest new mechanisms for a putative cardioprotective role of DHEA in corticosteroid-associated heart diseases.
authors: Service of Endocrinology, Diabetology, and Nutrition, University Hospital of Geneva, 4 Rue Gabrielle-Perret-Gentil, CH-1211 Geneva 14, Switzerland. tiphaine.mannic@hcuge.ch
authors: Tiphaine
authors: T
authors: Mannic
authors: Mounira
authors: M
authors: Mouffok
authors: Magaly
authors: M
authors: Python
authors: Takehisa
authors: T
authors: Yoshida
authors: Andres D
authors: AD
authors: Maturana
authors: Nicolas
authors: N
authors: Vuilleumier
authors: Michel F
authors: MF
authors: Rossier
mesh_terms: D000450:Aldosterone / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D020747:Calcium Channels, T-Type / Q000235:genetics / Q000378:metabolism; D002316:Cardiotonic Agents / Q000494:pharmacology; D049108:Cell Enlargement / Q000187:drug effects; D002478:Cells, Cultured; D003687:Dehydroepiandrosterone / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D018161:Receptors, Mineralocorticoid / Q000378:metabolism*
chemical_list: D000975:Antioxidants; C509958:Cacna1h protein, rat; D020747:Calcium Channels, T-Type; D002316:Cardiotonic Agents; D011965:Receptors, Glucocorticoid; D018161:Receptors, Mineralocorticoid; D003687:Dehydroepiandrosterone; D000450:Aldosterone