Prolactin and luteinizing hormone levels of prelaying, laying and postlaying turkey hens following central administration of serotonin and peripheral administration of quipazine maleate.

The influence of serotonin (5-HT) on plasma prolactin and LH levels in female turkeys was studied by systemic injection of quipazine maleate, at 5-HT agonist, or by cerebroventricular injection of 5-HT itself. Within 30 min after injection, quipazine maleate (20 mg administered i.p.) elicited a significant increase in plasma prolactin in hens approaching sexual maturity as well as in laying hens. A 5-mg dose. had no effect on prolactin levels of either prelaying or laying hens. Intraventricular injection of 5 and 25 micrograms of 5-HT caused an increase in plasma prolactin of prelaying hens. A 5-micrograms dose of 5-HT was also effective in increasing prolactin levels in laying hens and in hens that had stopped laying due to ventricular cannula implantation. Neither quipazine maleate nor intraventricularly injected 5-HT had an effect on LH levels in any experiment.