title: Mode of action of somatostatin in inhibiting parathyroid hormone secretion.
abstract: Effects of somatostatin on basal and low calcium-, isoproterenol- or dibutryl cyclic AMP (DBcAMP)-stimulated parathyroid hormone (PTH) secretion were evaluated in vitro with bovine parathyroid tissue. Low calcium, isoproterenol or DBcAMP alone significantly stimulated PTH secretion. Somatostatin 1 or 4 microgram/ml significantly inhibited these stimulated PTH secretions. Inhibition of isoproterenol-stimulated PTH secretion was more complete than was the inhibition of low calcium- or DBcAMP-stimulated secretion. The studies indicate that somatostatin inhibits PTH secretion by an action distal to cAMP generation. The more complete inhibition of isoproterenol-stimulated PTH secretion suggests that somatostatin may also have additional effects on or proximal to the formation of cyclic AMP.
mesh_terms: D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002417:Cattle; D000242:Cyclic AMP / Q000378:metabolism; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D010280:Parathyroid Glands / Q000187:drug effects / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000378:metabolism*; D013004:Somatostatin / Q000494:pharmacology*
chemical_list: D010281:Parathyroid Hormone; D013004:Somatostatin; D003994:Bucladesine; D000242:Cyclic AMP; D007545:Isoproterenol; D002118:Calcium