THE EFFECT OF ACTH ON THE FROG CHROMATOPHORES

Abstract

ACTH uniformly produced darkening of the dorsal skin of Hyla arborea in doses as small as .01 [mu]g. In frogs kept captive over a mo., .001 [mu]g. was the minimum effective dose. Intermedin caused an effect with 30 [mu]g., pitressin with 10 [mu]g., and thyrotropin, prolactin and gonadotropin only occasionally caused an effect with 100 [mu]g. Tests on 12 peripheral hormones (including estrogenic, androgenic and adrenal steroids, thyroxine, insulin, parathormone and epinephrine) and on 38 amines and amino acids were all negative. In view of the pigmentation of patients with adrenal insufficiency, and that produced in patients treated with ACTH, it is believed that the melanogenic effect is inherent in ACTH and probably represents one of the "ACTH factors.".