Format

Send to:

Choose Destination
See comment in PubMed Commons below
Cardiovasc Res. 2009 Jul 15;83(2):303-12. doi: 10.1093/cvr/cvp090. Epub 2009 Mar 17.

Growth hormone-releasing hormone promotes survival of cardiac myocytes in vitro and protects against ischaemia-reperfusion injury in rat heart.

Author information

  • 1Laboratory of Molecular and Cellular Endocrinology, Department of Internal Medicine, University of Turin, Corso Dogliotti 14, 10126 Turin, Italy. riccarda.granata@unito.it

Abstract

AIMS:

The hypothalamic neuropeptide growth hormone-releasing hormone (GHRH) stimulates GH synthesis and release in the pituitary. GHRH also exerts proliferative effects in extrapituitary cells, whereas GHRH antagonists have been shown to suppress cancer cell proliferation. We investigated GHRH effects on cardiac myocyte cell survival and the underlying signalling mechanisms.

METHODS AND RESULTS:

Reverse transcriptase-polymerase chain reaction analysis showed GHRH receptor (GHRH-R) mRNA in adult rat ventricular myocytes (ARVMs) and in rat heart H9c2 cells. In ARVMs, GHRH prevented cell death and caspase-3 activation induced by serum starvation and by the beta-adrenergic receptor agonist isoproterenol. The GHRH-R antagonist JV-1-36 abolished GHRH survival action under both experimental conditions. GHRH-induced cardiac cell protection required extracellular signal-regulated kinase (ERK)1/2 and phosphoinositide-3 kinase (PI3K)/Akt activation and adenylyl cyclase/cAMP/protein kinase A signalling. Isoproterenol strongly upregulated the mRNA and protein of the pro-apoptotic inducible cAMP early repressor, whereas GHRH completely blocked this effect. Similar to ARVMs, in H9c2 cardiac cells, GHRH inhibited serum starvation- and isoproterenol-induced cell death and apoptosis through the same signalling pathways. Finally, GHRH improved left ventricular recovery during reperfusion and reduced infarct size in Langendorff-perfused rat hearts, subjected to ischaemia-reperfusion (I/R) injury. These effects involved PI3K/Akt signalling and were inhibited by JV-1-36.

CONCLUSION:

Our findings suggest that GHRH promotes cardiac myocyte survival through multiple signalling mechanisms and protects against I/R injury in isolated rat heart, indicating a novel cardioprotective role of this hormone.

PMID:
19293247
[PubMed - indexed for MEDLINE]
Free full text

Publication Types, MeSH Terms, Substances

Publication Types

MeSH Terms

Substances

PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Write to the Help Desk