Acetylcholine induced responses of plasma LH and prolactin in normal and 6-hydroxydopamine-treated rats

The effects of intraventricular injection of acetylcholine at doses of 50 mug were studied in male rats. Under ether anesthesia, acetylcholine did not modify plasma prolactin and LH levels. Contrarily, in rats anesthetized with pentobarbital, acetylcholine at the same doses induced significant decreases of prolactin from 10 to 60 min postinjection. LH levels were not modified by treatment. Prolactin responses to acetylcholine were absent during the first 30 min postinjection in 6-hydroxydopamine-treated rats. Only a delayed response was detected. In these animals, icv administration of dopamine caused a clear decrease of plasma prolactin levels. A marked rise of LH at 30 and 60 min following acetylcholine injection was found in 6-hydroxydopamine-treated rats. Results suggest a catecholaminergic mediation of the prolactin and LH responses induced by acetylcholin in male rats.