Abstract
The growth hormone potencies of pituitaries obtained from fish, frog, turtle, chicken, rabbit, cat, horse, and whale were compared in the tibia test assay. A significant response was obtained with frog, horse, rabbit, whale, and cat pituitary suspensions. The pituitaries of chickens and turtles caused a small but nonsignificant increase in epiphyseal width, whereas fish pituitaries had no growth activity in the hypophysectomized rat.