Vasoactive properties of a parathyroid hormone-related protein in the rat aorta

Parathyroid hormone-related protein (PTHrP) or its mRNA transcripts have been documented in a variety of normal tissues, including vascular smooth muscle. A synthetic amino-terminal fragment of PTHrP, PTHrP(1-34), was tested a) for its vasoactive properties in a perfused rat aorta and b) its ability to stimulate cAMP accumulation in cultured rat aorta smooth muscle cells; PTHrP(1-34) was a potent vasodilator and increased cAMP accumulation. The results confirm the potent vasorelaxant properties of PTHrP(1-34), and show that the peptide stimulates adenylate cyclase in vascular smooth muscle cells per se, suggesting, but not proving, linkage of cAMP accumulation to vasorelaxation.