Effect of clonidine, quipazine, and LY 53857 on the prolactin-suppressant action of bromocriptine in rats.
The alpha 2-adrenergic agonist clonidine hydrochloride, the serotonin agonist quipazine maleate, and the serotonin (5-HT2) antagonist LY 53857 were tested alone and in various combinations for their capabilities to increase mean serum prolactin (MSP) concentrations in rats given the synthetic ergot alkaloid CB-154 (2-bromo-alpha-ergocriptine), a known prolactin suppressor. The LY 53857 and the combination of clonidine, quipazine, and LY 53857 significantly decreased MSP concentrations. Quipazine given alone (10 mg/kg of body weight) was best able to increase MSP concentration and has potential to antagonize prolactin-depressant effects of ergot alkaloids.
D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology*; D003000:Clonidine / Q000494:pharmacology*; D004347:Drug Interactions; D004873:Ergolines / Q000494:pharmacology*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism; D011388:Prolactin / Q000097:blood* / Q000378:metabolism; D011804:Quinolines / Q000494:pharmacology*; D011814:Quipazine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012702:Serotonin Antagonists / Q000494:pharmacology*
D004873:Ergolines; D011804:Quinolines; D012702:Serotonin Antagonists; D001971:Bromocriptine; D011814:Quipazine; D011388:Prolactin; C032663:LY 53857; D003000:Clonidine