Antipsychotic drugs inhibit prolactin release from rat anterior pituitary cells in culture by a mechanism not involving the dopamine receptor.
Bromocriptine, a dopamine agonist, inhibited secretion of PRL and did not affect GH release from rat anterior pituitary cells in culture. The reversal of this inhibition of PRL release by butaclamol, a dopamine antagonist, was stereospecific; 10 nM d-butaclamol completely reversed the inhibition caused by 10 nM bromocriptine, while l-butaclamol had no effect at concentrations up to 10 microM. However, both enantiomers at 10 microM inhibited PRL release to 30% and GH release to 91% of control values. Two other dopamine antagonists also inhibited hormone release. Haloperidol (10 microM) inhibited PRL release to 23% of control values and did not affect GH release; 3.3 microM pimozide inhibited PRL and GH release to 18% and 38% of control values, respectively. These data indicate that, the inhibition of PRL by antipsychotic drugs is not mediated through the dopamine receptor.
D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology*; D002069:Butaclamol / Q000494:pharmacology*; D002478:Cells, Cultured; D003986:Dibenzocycloheptenes / Q000494:pharmacology*; D013006:Growth Hormone / Q000378:metabolism; D007700:Kinetics; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011954:Receptors, Dopamine / Q000502:physiology*; D013644:Tartrates / Q000494:pharmacology
D003986:Dibenzocycloheptenes; D011954:Receptors, Dopamine; D013644:Tartrates; D001971:Bromocriptine; D011388:Prolactin; D013006:Growth Hormone; D002069:Butaclamol