Parathyroid hormone responses to the dopaminergic agonist 2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene.
Plasma parathyroid hormone (PTH) responses to the dopaminergic agonist 2-amino-6,7-(OH)2-1,2,3,4-tetrahydronaphthalene (ADTN) have been studied in cattle. During ADTN infusions PTH increased within min in a dose-dependent manner, while calcium remained unchanged. Prolonged administration of ADTN caused transient PTH responses and crosstachyphylaxis to the subsequent administration of the beta-adrenergic agonist isoproterenol, but not to hypocalcemia, caused by infusions of ethylene-glycol-bis (beta-aminoethylether)-N,N'-tetraacetate. PTH responses were not modified by the beta-adrenergic blocking agent propranolol, infused in amounts earlier shown to suppress PTH responses to isoproterenol and epinephrine. In conclusion, the dopaminergic agonist ADTN caused a direct and transient stimulation of PTH secretion, not mediated by hypocalcemia or by beta-adrenergic receptors on parathyroid cells. However, crosstachyphylaxis to isoproterenol, but not to hypocalcemia, was observed.
D000818:Animals; D002118:Calcium / Q000097:blood; D002417:Cattle; D004298:Dopamine / Q000502:physiology*; D007263:Infusions, Parenteral; D008297:Male; D009281:Naphthalenes / Q000494:pharmacology*; D010281:Parathyroid Hormone / Q000097:blood*; D011433:Propranolol / Q000494:pharmacology; D013764:Tetrahydronaphthalenes / Q000008:administration & dosage / Q000494:pharmacology*
D009281:Naphthalenes; D010281:Parathyroid Hormone; D013764:Tetrahydronaphthalenes; C011639:ADTN; D011433:Propranolol; D002118:Calcium; D004298:Dopamine