title: Calcium-controlled secretion is effected through a guanine nucleotide regulatory protein in parathyroid cells.
abstract: Calcium regulates parathyroid secretion through mechanisms yet to be elucidated. We have investigated this phenomenon through use of pertussis toxin which catalyzes ADP-ribosylation and inactivation of a guanine nucleotide regulatory protein, possibly Ni or No. Calcium inhibition of PTH release is blocked in cells treated with pertussis toxin, and there is concomitant ADP-ribosylation of a 40-kilodalton protein. The ionophore A23187 inhibits secretion in toxin-treated as well as in control cells. We conclude that a guanine nucleotide regulatory protein is involved in calcium regulation of PTH secretion at a locus proximal to the intracellular site effecting inhibition of secretion.
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D019204:GTP-Binding Proteins / Q000502:physiology*; D010280:Parathyroid Glands / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000378:metabolism*; D037342:Pertussis Toxin; D012636:Secretory Rate / Q000187:drug effects; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
chemical_list: D010281:Parathyroid Hormone; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D000001:Calcimycin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D002118:Calcium