Effect of Sodium Hydroxide on the Melano‐phore‐expanding Properties of Pituitary Extracts

A Purified Extract of the Intermediate Lobe of the Pituitary

“…The term " protection" has been retained to describe this prolongation in order to avoid ambiguity, though it is not certain that the parent assumption is correct, namely, that such treatment results in an activity less easily destroyed by the body. Experiments on melanophores in isolated skin of dogfish show that treatment of extracts with NaOH results in both " potentiation " and " protection " [Landgrebe et al, 1950]. So if the "protection" shown by isolated skin melanophores is the same as that shown in the intact animal, it cannot be argued that it is the reduced rate of destruction by body tissue other than skin which gives the protection.…”

“…3 shows that after adjusting a dilute solution (10 "I.U."/ml.) to pH 13 with N sodium hydroxide and heating for two minutes on a boiling water bath [Landgrebe et al, 1950], the response curve of both the International Standard Posterior Lobe Pituitary (I.S. PLP) and the purified "B" is prolonged.…”

“…Some workers have deliberately destroyed these contaminants by alkaline treatment of their original extract before purification. Such treatment, however, changes the character of the "B ", and the material is qualitatively different from that present in simple extracts [Landgrebe, Munday and Waring, 1950]. Our method necessitates no such treatment and allows recovery of pressor and oxytocic activity.…”