Role of anions in parathyroid hormone release from dispersed bovine parathyroid cells.

Abstract

Parathyroid hormone [PTH] release was inhibited 60-80% by decreasing [Cl-] or [OH-] and 60-70% by replacement of NaCl with the impermeant anion isethionate. Substitution of various monovalent cations in the medium had no effect on the release. Disodium 4-acetamido-4''-isothiocyanostilbene-2,2''-disulfonate (SITS) and probenecid, which block anion transport in the erythrocyte, caused a dose-dependent 90-100% inhibition of release. Kinetic analysis of inhibition by probenecid suggested that it was competitive with respect to OH- or Cl-. Anions and the anion transport system may play a role in exocytosis of a polypeptide hormone. The proton inophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone apparently blocked hormone release, and the possibility of a chemosmotic mechanism for exocytosis in this system similar to that previously postulated for chromaffin granules and platelets is discussed.