Dopaminergic stimulation of cyclic AMP accumulation and parathyroid hormone release from dispersed bovine parathyroid cells.
The effects of dopaminergic agonists and antagonists have been studied in dispersed bovine parathyroid cells. Dopaminergic agonists caused a transient 20- to 40-fold increase in cellular cyclic AMP and a 2- to 3-fold increase in parathyroid hormone release. Dose-response relationships were similar for cyclic AMP accumulation and hormone release, whether studied by increasing agonist concentration or by increasing concentration of antagonist with constant agonist. The effects on the dopamine receptor could be differentiated from those of the previously characterized beta-adrenergic receptor by specific inhibitors. These results appear to represent proof with a homogeneous cell population that dopaminergic receptors linked to adenylate cyclase can regulate a secretory process mediated by cyclic AMP. This system should be useful in further studies on dopamine receptors and should provide a valid tool for determining interactions of radiolabeled ligands with such receptors.
Dopaminergic stimulation of cyclic AMP accumulation and parathyroid hormone release from dispersed bovine parathyroid cells. The effects of dopaminergic agonists and antagonists have been studied in dispersed bovine parathyroid cells. Dopaminergic agonists caused a transient 20- to 40-fold increase in cellular cyclic AMP and a 2- to 3-fold increase in parathyroid hormone release. Dose-response relationships were similar for cyclic AMP accumulation and hormone release, whether studied by increasing agonist concentration or by increasing concentration of antagonist with constant agonist. The effects on the dopamine receptor could be differentiated from those of the previously characterized beta-adrenergic receptor by specific inhibitors. These results appear to represent proof with a homogeneous cell population that dopaminergic receptors linked to adenylate cyclase can regulate a secretory process mediated by cyclic AMP. This system should be useful in further studies on dopamine receptors and should provide a valid tool for determining interactions of radiolabeled ligands with such receptors.