Luteinizing Hormone-Releasing Activity in Plasma of Hypophysectomized Rats

Abstract

Plasma from hypophysectomized female rats (2–3 months postoperatively) produced ovarian ascorbic acid depletion when administered intravenously to immature females which had been pretreated with gonadotrophins. This activity was absent from plasma of hypophysectomized rats with median eminence lesions but was still present after lesions in the dorsal hypothalamus. Plasma from rats hypophysectomized for a week or less was devoid of activity. It was concluded that plasma from long-term hypophysectomized rats contains a circulating luteinizing hormone-releasing factor (LH-RF) which vanishes after destruction of the site of storage of the LH-RF in the median eminence. (Endocrinology76: 272, 1965)