NEURAL ACTIVATION OF GONADOTROPIC HORMONE RELELEASE BY ELECTRICAL STIMULATION IN HYPOTHALAMUS OF GUINEA PIG AND RAT

Ovulation or advanced preovulatory changes occur in the follicles of guinea pig ovaries in late diestrus, following electrical stimulation through paired platinum electrodes in various hypothalamic regions. Comparative studies in rats reveal that the areas that respond to such stimulation by causing LH release are similar, that is, the preoptie area, anterior hypothalamus, and the arcuate-nuclear region; but when electrodes arc more anterior or posterior to those regions, no LH release occurs. In addition, it has been determined in Wistar rats that somewhere between 45 min to 60 min is required to induce full ovulation in all animals. With slightly greater amounts of stimulation, about 75-78% of guinea pigs respond by showing either advanced preovulatory changes or ovulation. © 1969 S. Karger AG, Basel.