HEMODYNAMIC-EFFECTS OF PARATHYROID HORMONE-RELATED PEPTIDE-(1-34) IN HUMANS

It has been suggested that PTH-related peptide-(1-34) (PTHrP) is a reg ulator or modulator of regional or systemic cardiovascular function wi th varying vasodilating actions in different species. We have studied the cardiovascular pharmacodynamic profile of PTHrP in healthy humans. In a double blind, placebo-controlled, cross-over study design, eight healthy subjects were assigned to stepwise increased iv doses of PTHr P. In addition, a dose-response curve to PTHrP was constructed in a do rsal hand vein in eight subjects. PTHrP dose-dependently increased pul se rate and renal plasma flow by more than 50% (P < 0.0001 for both pa rameters, by ANOVA), but only a small venodilating response was seen i n hand vein experiments, and no effect was noted on mean arterial bloo d pressure or cardiac inotropic performance. Although it is unlikely t hat PTHrP regulates systemic hemodynamics, its chronotropic effect and its patent action on renal plasma flow may represent the primary card iovascular physiological targets of action.