Mechanism of Copper-Induced Ovulation by the Incubation Experiment of the Anterior Pituitary Gland

  • SUZUKI MASAKUNI
    Department of Obstetrics and Gynecology, Tohoku University School of Medicine
  • HIROI MASAHIKO
    Department of Obstetrics and Gynecology, Tohoku University School of Medicine
  • TAKAHASHI TAKESHI
    Department of Obstetrics and Gynecology, Tohoku University School of Medicine

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In this experiment a method of incubating the anterior piuitaries of male rats in vitro was used to study the neurohumoral regulation of hypothalamus on the pituitary. Based on the fluctuation of the gonadotropins upon the addition of crude hypothalamic extract and copper salt in the incubation medium the mechanism of copper-induced ovulation was studied. For the measurement of the gonadotropins the ascorbic acid depletion method of Parlow was used for LH, the rat's ovarian weight measuring method of Steelman-Pohley was employed for FSH, and the methed of measuring the dry weight of pigeon crop sac mucosa of Nicoll for prolactin was employed. The measurement of the gonadotropins in the incubation medium was possible upon selection of an adequate amount of anterior pituitary tissue and the proper incubation time. The gonadotropins from an anterior pituitary in the medium after incubation for 2 hours were in the range of 0.2-0.8μg of LH (NIH-LH-S12), 11-23μg of FSH (NIH-FSH-S4), and 1.0-44mU of prolactin (NIH-P-B2), corresponding to conditions of the incubation. The significant increase of the LH and FSH activities and decrease of the prolactin activity after the addition of hypothalamic extract suggest the presence of LH, FSH releasing-factor and prolactin inhibiting-factor. The addition of cerebral cortex of posterior pituitary component caused no such fluctuations. A single addition of the copper-salt produced only an increase of prolactin. The addition of the hypothalamus and copper-salt caused a significant increase of LH and FSH. These results would suggest the action of copper-salt on the hypothalamus to release LH and FSH as the mechanism of the copper-induced ovulation.

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