The influence of long term estrogen treatment on plasma prolactin levels induced by ether anesthesia in ovariectomized rats.

2 methods of continuous estrogen delivery, polyestradiol phosphate injection and implantation of Silastic capsules of estradiol-17 beta, in ovariectomized rats induced increases in plasma prolactin in the afternoon (15.00-17.00) beginning at 1 week and continuing for 4-8 weeks. In addition these methods of estrogen treatment potentiated the ether-induced increase in plasma prolactin in the morning (9.00-11.00) beginning on week 2 and continuing for 3-8 weeks. These results indicate that estrogen activates the mechanisms that cause an afternoon surge in prolactin before potentiating a morning elevation induced by ether anesthesia.