INHIBITION OF OVULATION IN THE RABBIT BY THE ADRENERGIC-BLOCKING AGENT DIBENAMINE

Abstract

INTRODUCTION In previous papers (Markee, Sawyer and Hollinshead, 1946, 1947 a, b) we have reported the results of investigations of the mechanism by which the central nervous system exerts its control over the release of luteinizing hormone in the rabbit. Using unipolar and bipolar electrical stimulation of known voltage and current we found that direct stimulation of the hypophysis by a unipolar electrode was effective in producing ovulation in the rabbit only with relatively strong currents, which gave signs of considerable spread to the central nervous system. On the other hand, localized bipolar stimulation of the hypothalamic region with a current which was ineffective when applied by the same electrode directly to the hypophysis, produced ovulation in three out of four animals. From these results we concluded that the pathway of excitation from the hypothalamus to the anterior lobe of the hypophysis was probably not through thehypothalamico-hypophyseal nerve tract,