The effect of copper salts on ovulation, especially on hypothalamic ovulatory hormone releasing factor.

In this study the influence of copper salts on the hypothalamic ovulatory hormone releasing factor was studied in vivo. 321 healthy adult female rabbits were used. 85 mcg of estradiol-17-beta-benzoate dissolved in 1 ml of sesame oil was injected intramuscularly for 2 days. Absence of ovulation and an active corpus luteum were confirmed by laparotomy. (For the measurement of LH rats were injected with 1000 IU of PMS and 64 hours later with 50 IU of HCG subcutaneously. Bioassay was conducted 7 days after the HCG injection. For the gonadotropin, the Teikoku Zoki preparation which contains 1000 IU in one ampule as HCG preparation and Serotropin which contains 1000 IU in one ampule as PMS preparation were used. NIH-LH-S-four was used as the standard LH.) The crude hypothalamic extract was prepared from the hypothalamus of freshly sacrificed rabbits by the Nikitovitch-Winer method and homogenized with .5% acetic acid at 0 degrees C. .05 ml of 1% cupric sulfate was added to one sample and similarly homogenized. As controls .2%, 1%, and 5% cupric sulfate solutions were mixed with cerebral cortex tissue and centrifuged, boiled, and stored frozen in the same manner. For the study, rabbits pretreated with 100 mcg of estrogen for 2 days were sacrificed at intervals from 30 minutes to 12 hours after the iv. The hypothalamus was removed and the presence or absence of ovulation was noted. Crude hypothalamic extract was injected into the pituitary and the increase of the rate of ovulation noted as the concentration of the extract rose. Injection into the pituitary of the crude hypothalamic extract prepared in the presence of copper caused a pronounced increase in the rate of ovulation. The increase was proportional to the increase in the concentration of copper and greater than after the extract without the copper. Ovulation after injection of the hypothalam ic extract was greatest when prepared within 1 hour after iv injection of cupric sulfate but no ovulation occurred when the extract was prepared 12 hours later. Findings suggest that induction of ovulation through the action of copper is on the ovulatory hormone release factor probably present around the median eminence of the hypothalamus.