PTH-related protein and Type 1 parathyroid hormone receptor mRNA expression in rat ventricular myocardial hypertrophy

Antony Halapas, Peter Lembessis, Antigone Sourla, Costas Pantos, Dennis V Cokkinos and Michael Koutsilieris

Background: Parathyroid hormone related protein (PTHrP) and Type 1 PTH receptor (PTH-1.R) bioregulation system exerts positive inotropic and chronotropic actions on myocardium, in vivo, and it is implicated in cell-cell interactions, which can lead to myocardial hypertrophy. Objective: Herein we analyzed the expression of PTHrP and PTH-1.R (mRNA and protein) in adult male Wistar rat ventricular myocardium after the induction of myocardial hypertrophy using aortic constricted and hyperthyroid models.
Materials & methods: Expression of PTHrP and PTH-1.R mRNA was studied by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR) while nature of the PCR products was confirmed by direct DNA sequence. The expression of PTHrP and PTH-1.R in rat ventricular myocardium was confirmed using Western blot and immunocytochemistry analysis.
Results: Our data showed that aortic banding-induced ventricular hypertrophy was associated with an increase of PTHrP mRNA expression while hyperthyroid-induced ventricular hypertrophy was associated with PTH-1.R (mRNA and protein) overexpression in rat myocardium.
Conclusion: Transcriptional changes of PTHrP/PTH-1.R bioregulation system are differentially regulated in aortic constricting-induced and hyperthyroid-induced rat ventricular hypertrophy.