THE DOPAMINE RECEPTOR IN THE INTERMEDIATE LOBE OF THE RAT PITUITARY-GLAND IS NEGATIVELY COUPLED TO ADENYLATE-CYCLASE

The potency of a series of drugs [lisuride, 2-bromo-.alpha.-ergocryptine, pergolide, dihydroergocryptine, apomorphine, lergotrile, dopamine, (-)norepinephrine, (-)epinephrine] to inhibit cAMP accumulation in cells of the intermediate lobe of the rat pituitary gland in culture is typically dopaminergic. The dopaminergic antagonists spiroperidol, thioproperazine, domperidone, haloperidol, (-)sulpiride, fluphenazine, pimozide, (+)butaclamol, metoclopramide, (+)sulpiride, (-)butaclamol reverse the inhibition of cAMP levels according to their known pharmacological activity. Activation of the dopamine receptor in pars intermedia cells leads to inhibition of basal cAMP accumulation and suggests that this receptor is negatively coupled to adenylate cyclase.