Normalizing effect of Ca2+ ionophore on cytoplasmic Ca2+ and parathyroid hormone release of dispersed parathyroid cells from patients with hyperparathyroidism.
The effects of the Ca2+ ionophore A23187 on parathyroid hormone (PTH) secretion and cytoplasmic free Ca2+ concentration (Ca2+i) were measured at different extracellular Ca2+ concentrations using dispersed cells from patients with hyperparathyroidism (HPT). The addition of a low concentration of the Ca2+ ionophore to quin2-loaded cell preparations resulted in the apparent normalization of calcium-regulated Ca2+i. At all extracellular calcium concentrations Ca2+i reached significantly higher values in the presence of the ionophore and the dose-response relationship was shifted to the left. Under similar conditions calcium-regulated PTH release was correspondingly corrected with an increased suppressibility and left-shifted dose-response relationship. The data render strong support for a disturbed regulation of Ca2+i as a major factor in the pathophysiology of HPT.
D000634:Aminoquinolines; D000001:Calcimycin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D005456:Fluorescent Dyes; D006801:Humans; D006961:Hyperparathyroidism / Q000378:metabolism*; D010280:Parathyroid Glands / Q000187:drug effects / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
D000634:Aminoquinolines; D005456:Fluorescent Dyes; D010281:Parathyroid Hormone; D000001:Calcimycin; C035739:Quin2; D002118:Calcium