Blockade of Neurogenic Stimulation of the Rabbit Adenohypophysis by Banthine

Abstract

Banthine (beta-diethylaminoethyl xanthene-9-carboxylate methobromide) blocks copulation-induced ovulation in the rabbit, a species in which release of ovulating hormone from the adenohypophysis is normally activated by neurogenic stimuli attendant upon coitus. The study empoloyed 55 female rabbits, and only mature estrous animals were mated. The new anticholinergic agent was effective only if injd. within a few minutes post coitum, whereas the hypophysis requires about an hour to liberate an ovulating quantum of LH; thus it is apparent that Banthine blocks the neurogenic stimulus rather than the pituitary release mechanism. Rapid postcoital intraven. injns. of other agents including procaine, SC-1950 (ganglionic blocking agent), Pentothal (anesthetic) and Neo-Antergan (antihistaminic) tailed to block pituitary stimulation. The blocking dose of Banthine was found to develop protection against twice-lethal dosages of acetylcholine within a few seconds. The results parallel those of our earlier work with atropine and are interpreted as confirmation of the existence of a rapid cholinergic component in the neurogenic stimulus for the release of ovulating hormone in the rabbits.