Inhibition of parathyroid hormone release from dispersed bovine cells by ouabain.
Ouabain, at concentrations of 3 X 10(-4)-10(-3) M, inhibited secretion of PTH approximately 50% in a freshly dispersed bovine parathyroid cell preparation. This inhibition was found with both unstimulated and secretagogue-stimulated PTH release. Reductions in PTH secretion were found at all concentrations of Ca++ tested between 0.3 mM and 2.0 mM and in the presence of the divalent cation chelators EDTA and EGTA, indicating that extracellular Ca++ is not an absolute requirement for the inhibition. The ouabain inhibition did not appear to be mediated through changes in either adenylate cyclase activity or total cellular cAMP, implying a locus distal to the generation of this cyclic nucleotide. The data suggest that transmembrane potential and/or distribution of monovalent cations across the plasma membrane is important in the maintenance of PTH secretion. The mechanisms involved in this control do not appear to involve extracellular Ca++ directly.
D000818:Animals; D003994:Bucladesine / Q000037:antagonists & inhibitors; D002118:Calcium / Q000502:physiology; D002417:Cattle; D002614:Chelating Agents / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D018492:Dopamine Antagonists; D066298:In Vitro Techniques; D010042:Ouabain / Q000494:pharmacology*; D010280:Parathyroid Glands / Q000187:drug effects* / Q000378:metabolism; D010281:Parathyroid Hormone / Q000378:metabolism*
D002614:Chelating Agents; D018492:Dopamine Antagonists; D010281:Parathyroid Hormone; D010042:Ouabain; D003994:Bucladesine; D000242:Cyclic AMP; D002118:Calcium