Gonadotropic Extracts from the Leaves of Young Oat Plants

Abstract

By the use of the Katzman-Doisy benzoic acid procedure it was found possible to obtain gonadotropic extracts from alfalfa leaf meal. 1 It was, however, difficult to obtain active extracts uniformly from commercial samples available, and it was not found possible to arrange for a dependable supply of alfalfa meal of known age and history. The work of Schnabel 2 on the biologic value of immature oat grass prompted an investigation of this material. The young oat leaves proved to be a better source of gonadotropin than alfalfa leaf, and more easy to obtain at the desired stage of growth. The plants were cut when 4 to 6 inches high and either cured in the sun or quickly dehydrated by the method commonly used for drying alfalfa commercially. Two crops were obtained from Kansas and 2 from the New Jersey State Agricultural Experiment Station at New Brunswick.† The extraction procedure has been modified to the extent of substituting 30% acetone for water as the medium for the extraction of the crude protein resulting from the benzoic acid precipitation.

Potent extracts have been repeatedly prepared from each of the 4 successive crops over a period of 3 years. With the present technique the dried oat leaves yield products which produce ovulation in the rabbit by the single intravenous injection of the equivalent of 30 to 80 gm. of the original dry leaf. The latent period, like that of post-coital ovulation, is less than 18 hours and thus differs from the process provoked by the injection of copper salts. 3 It is entirely possible that the activity in alfalfa and oat leaves is similar to the thermolabile component in yeast extracts which was found to be active in the hypophysectomized male rat by Hisaw and coworkers. 4