KOHN ON INTERMEDIN AND MELANIN SYNTHESIS

Abstract

It has been shown by Frieden and Bozer (1951), Fournier et al. (1943) and others that when preparations of intermedin, the melanophorotropic hormone of the pituitary intermediate lobe, are administered to animals, the amount of melanin pigment in the skins of the animals increases. Fostvedt (1940) reported that intermedin preparations had a stimulatory effect on reactions in which melanin is formed by the action of tyrosinase on tyrosine in vitro. Kohn (1952), in an abstract of preliminary experiments, reported that preparations of pituitary extracts treated according to the method of Landgrebe, Reid and Waring (1943) for intermedin purification reversed in vitro glutathione inhibition of several melanin-synthesizing systems, while other preparations with potent melanophore activity had no such effect. It is the purpose of this note to report subsequent investigations into the possible relationship between intermedin and melanin synthesis. EXPERIMENTAL METHODS AND RESULTS Tyrosinase was prepared by freezing 220 gm. of Psalliota campestris in a dry ice-acetone mixture,