MODES OF ANTERIOR HYPOTHALAMIC AREA AS REGULATORY CENTER FOR GONADOTROPIN RELEASE

  • 1 January 1977
    • journal article
    • research article
    • Vol. 70  (3) , 225-235
Abstract
The effects of the anterior hypothalamic area (AHA) implants of gonadal steroid estrogen and progesterone as well as the effects of electrical stimulation and electrolytic lesion confined in this area on the gonadotropin secretion were investigated in ovariectomized estradiol (20 .mu.g s.c.)-primed adult Wistar rats housed in a light and temperature controlled room. Progesterone implants evoked the rise of serum LH [luteinizing hormone] by 6 h whereas estradiol implants suppressed serum FSH by 24 h after implantation. Electrical stimulation effectively depleted both gonadotropins with a latency not shorter than 6 h. The lesion significantly prevented FSH elevation investigated at 72 h post ovariectomy and potentiated FSH secretion in response to estradiol treatment at 3 wk post ovariectomy. The result revealed the involvement of the AHA in the LH release mechanism which required progesterone activation while its involvement in the FSH regulatory mechanism depended upon estrogen. The area was elucidated as the inhibitory as well as the stimulatory loci for the feedback action of estrogen on FSH release.