Serotoninergic drugs affect prolactin and growth hormone secretion in the domestic fowl.

Adult fowl of both sexes injected with the monoamine oxidase inhibitor pargyline showed elevated circulating prolactin concentrations and reduced growth hormone concentrations. Young cockerels injected with the serotonin agonist quipazine and the antagonist methysergide showed responses consistent with a serotoninergic stimulatory control of prolactin. Injection of the serotonin precursor tryptophan and the serotonin re-uptake blocker imipramine resulted in elevated prolactin and reduced growth hormone levels. The similarities and differences in the control of prolactin and growth hormone in birds and mammals were discussed.