DIRECT HORMONE INACTIVATION BY EXTRACTS OF LITHOSPERMUM RUDERALE

Abstract

SUMMARY 1. The inhibiting action of extracts of Lithospermum ruderale (lithosperm) when mixed with various hormones has been described. 2. Pituitary gonadotrophin, prolactin (luteotrophin), thyrotrophin and pregnant mares' serum gonadotrophin (PMS) are readily inactivated. Chorionic gonadotrophin is less readily affected, and pituitary growth hormone and ACTH are unaffected by the concentration of lithosperm which inactivates the other hormones. Insulin and posterior pituitary hormones are equally unaffected. 3. PMS 'inactivated' by lithosperm is still capable of causing marked interstitial cell stimulation of the ovary of the intact rat with resulting oestrogen production. Hypophysectomy abolishes this reaction. 4. Various factors influencing the in vitro inactivation have been described, so that a standard method could be developed for testing fractions obtained in purifying lithosperm extracts. 5. Some preliminary extraction methods are discussed.