Ovulation Induced by Implantation of Cupric Sulfate Into the Brain of the Rabbit

Abstract

Although many reports are available on the induction of ovulation by copper salts, the site of action of Cu++ has not yet been explained. In order to elucidate this, cupric sulfate was implanted into the brain of adult female rabbits and examined whether or not it led to ovulation. In the present investigation, ovulation was noted following the implantation of less than 100 [mu]g of cupric sulfate into the basal tuberal area, but no other region, of the hypothalamus. Comparable implantation of less than 100 [mu]g of cupric sulfate into the anterior pituitary gland led to ovulation in only 6 of 22 does. In these, histologic effects of the copper were found in the median eminence, superior to the pituitary gland. No ovulation occurred in rabbits in which the effects were confined to the anterior pituitary gland. Implantation in the limbic system (amygdala) resulted in no ovulation in 5 of 6 animals. For closer investigation of the site of action, less than 50 [mu]g of cupric sulfate was implanted. Ovulation was then noted in all the animals with implants in the posterior median eminence and in none with implants in the other areas (anterior pituitary, etc.). The periods of time from the implantation of cupric sulfate to ovulation ranged from 18 to 48 hr.