Relationship of intracellular 3',5'-adenosine monophosphate accumulation to parathyroid hormone release from dispersed bovine parathyroid cells.

Abstract

The relationship of cAMP accumulation to PTH release was investigated in dispersed bovine parathyroid cells. Intracellular cAMP was stimulated 3-fold by 2 × 10-4 M methylisobutylxanthine, a potent phosphodiesterase inhibitor, and 40 to 60-fold by 10-6 M (–)Isoproterenol. Increases in intracellular cAMP, were accompanied by release of cAMP into the extracellular space, and this release was inhibited by probenecid. Increased intracellular cAMP in response to (–)isoproterenol wag42:113 s accompanied by a rapid increase in parathyroid hormone (PTH) release. Both increased cAMP accumulation and PTH release due to β-adrenergic agonists were rapidly reversed (within 3 min) by (–)propranolol, suggesting that intracellular cAMP regulates the rate of hormone release. The increased rate of PTH release due to a variety of agonists (β-adrenergic, dopaminergic, and secretin) was linearly related to the logarithm of the increment in intracellular cAMP. This relationship was independent of the agonist employed and was al...