The gonadotropic hormone of the blood of the pregnant mare has been greatly concentrated by adsorption on active aluminum hydroxide followed by elution. The preparations so obtained gave demonstrable gonadotropic effects within 100 hours in 21 day old female mice following three subcutaneous injections of 0.001 mg. in 1 cc. of physiological saline.
As is well known, other gonadotropic substances do not cause conspicuous development of the male gonads but injections of comparatively large doses of these preparations into immature male rats caused marked development of the testes, which in 10 days were trebled in weight. An astonishing increase in the weight of the seminal vesicles resulted, for these organs were approximately 75 times heavier than in controls.