The influence of pineal activation, removal or denervation on hypothalamic luteinizing hormone-releasing hormone activity: an in vitro study.

Female rats between 23 and 25 days of age were left intact or rendered either blind-anosmic, blind-anosmic-pinealectomized, blind-anosmic-superior cervical ganglionectomized or blind-anosmic-nervi conarii transected. Five weeks later the medial basal hypothalamic luteinizing hormone-releasing hormone (LRH) activity of each group of animals was assessed in vitro. The medial basal hypothalamic LRH activity in the blind-anosmic animals was greater than that of the intact rats. Pinealectomy, superior cervical ganglionectomy and nervi conarii transection were equally effective in reversing the effects of blinding and anosmia on LRH activity.