Studies on transplantations of amphibian anterior pituitary into chick embryo. Analysis of induction capacity by differential solubility and precipitation method.

SINCE the discovery by Bautzmann, Holtfreter, Spemann & Mangold (1932) that a diffusion of inducing substance takes place from the inductor into the competent reacting tissue, protein and ribonucleic acid have been favoured by candidates for the study of the nature of the inducing substance (see Brachet, 1960a, b). Recently Mangold, Tiedemann & Woellwarth (1956) studied the inductive capacity of ox anterior pituitary in gastrulae of Triton alpestris. It was found to have considerable inductive power. They suggested that the gonadotropic hormones or the growth hormone might be the active principle of induction. These hormones are glycoprotein or simple protein in nature and hence it was felt desirable to study the inductive capacity possessed by fresh anterior pituitary gland by resorting to differential solubility and precipitation of the various glycoprotein, protein and ribonucleic acid (RNA) constituents of the gland.