INSECT HORMONES IN VERTEBRATES - ANABOLIC EFFECTS OF 20-HYDROXYECDYSONE IN JAPANESE-QUAIL

Ecdysteroids are hormones controlling cell proliferation, growth and t he developmental cycles of insects and other invertebrates(1). They ar e occasionally present in various unrelated plants for no apparent rea son; no phytohormonal function has yet been identified. In certain cas es, ecdysteroids are accumulated to high levels in leaves, roots or se eds. Some ecdysteroid-containing plants have been known as medicinal p lants for centuries. One of them, Leuzea carthamoides Iljin (Asteracea e), growing in Central Asia, contains 0.4% ecdysteroid in dry roots an d 2% in seeds. A pharmacological preparation from this plant, 'Ecdiste n', is already available as a commercial preparation for its anabolic, tonic and other effects, for medical use (review(2)). It remained pro blematic, however, whether ecdysteroids were truly responsible for the se effects, because Leuzea contains a number of other biologically act ive compounds in addition to ecdysteroids. We extracted and purified e cdysteroids from the seeds of Leuzea. With 6 g of 96% 20-hydroxyecdyso ne (20E), we made a large-scale feeding assay with Japanese quail to f ind out whether ecdysteroid alone could duplicate the anabolic effects of the seeds. We found that the 96% ecdysteroid increased the mass of the developing quails in a dose-dependent manner, with the rate of in crease proportional to the ecdysteroid content in the seeds; there was a 115% increase in living mass with 100 mg kg(-1) of pure 20E compare d with 109.5% increase with 100-180 mg kg(-1) 20E equivalents in the s eeds. We conclude that the plethora of growth-promoting, vitamin-like effects induced in vertebrates by Leuzea is mediated by ecdysteroids.