title: Parathyroid hormone causes a transient rise in intracellular ionized calcium in vascular smooth muscle cells.
abstract: The effect of parathyroid hormone on intracellular calcium concentration in vascular smooth muscle cells in culture was studied. Human PTH 1-34 (hPTH (1-34)) caused a transient rise in intracellular calcium in a dose-dependent manner at physiological concentrations. The effect of PTH was mimicked by dibutyryl cyclic AMP and inhibited by a PTH receptor antagonist. The effect of PTH was increased in parallel with extracellular calcium concentration and a sustained response was observed when extracellular calcium was 2 mM or higher. The PTH action was blocked by nisoldipin, a calcium antagonist, but not by ouabain, a Na, K-ATPase inhibitor. These data indicate that PTH increases intracellular calcium through its receptor via opening calcium channels. A possible role of this effect in the regulation of vascular tone is also discussed.
authors.affiliation: Department of Cell Biology, Tsukuba Research Laboratories, Yamanouchi Pharmaceutical Co., Ltd., Ibaraki, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kawashima
mesh_terms: D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D015737:Nisoldipine / Q000494:pharmacology; D010281:Parathyroid Hormone / Q000494:pharmacology*; D051381:Rats
chemical_list: D002121:Calcium Channel Blockers; D010281:Parathyroid Hormone; D015737:Nisoldipine; D004533:Egtazic Acid; D003994:Bucladesine; D002118:Calcium